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Adjustable Bridge

I have an Epiphone acoustic guitar that I really like, my girlfriend gifted it to me after her uncle gifted it to her (she doesn't play, fingers are too small). It's the FT-130. It basically has two large screws, one on either side of the bridge, If anyone is familiar with this style of adjustable bridge can you please either tell me how to use it or send me a link to a site that will? the action is pretty low on the high strings and I'm getting a lot of buzzing (more than I should). Thanks for any help you can give!

Topic by HAL 9000    |  last reply


Accurate adjustable resistor?

I need a simple, low cost, small device capable of 10 different resistance settings, and must be capable of mechanically reproducing them exactly, on command.  It cannot be a potentiometer, as it is innacurate without some sort of  measurement device (which I cannot use), nor a rotart switch or encoder (too big and expensive, cannot use digital).  Basically, is there some alternative <$2 that will do this.  Again, no digital stuff or measuring position, only going between several set resistance settings (but any incrament thereof is okay).   

Question by jduffy54    |  last reply


Adjustment of the speed of a DC motor Answered

I'm working on something that requires a very low speed motor (~.5-4 RPM). I found a motor that runs at 1.5v @ a maximum of 7rpm (5040RPM max with 1428:1 ratio) I need however, something to lower and raise the speed of this motor. I know that people say PWMs for this, but the only one I can find is a 12 volt and has gotten mediocre reviews. Could I use this 12 volt PWM in this system, or could someone point me to a reasonable PWM that would work?

Question by sblaptopman    |  last reply


Adjustable Teeth comb

My innovative idea is regarding an adjustable teeth comb. There are Many type of combs available in the market but problem is that one's cannot use all these types of combs at a time. There are wide teeth comb,semiwide teeth,and fine teeth combs are available in the market.To prevent the hair loss it is very necessary to find right teeth comb. The solution is here in this Idea. Discription: As per sketch there is a wide teeth comb and each teeth will have 1 cm.space with each other teeth. There will be an another comb which will slide on the wide teeth comb. The sliding comb will work in this way that the User can set the teeth of comb as per his desire or as per his hair style requirement. After setting the teeth the slider comb will be locked.In another words it will work like "Sliding Cutter mechanism". In this way this product will work. Salient features: (1) No need of buying different teeth comb as one's can set the space of teeth of this comb (0.5 mm to10mm) and this adjustable comb will work to prevent hair damage as it will not intangled with hair. (2) low cost (3) easy to use (4) light weight (5) easy to clean (6) Prevent Hairloss or suitable for all kinds of hair style. (7) Both Female and Male can use it. (8) very useful to detangle hair due to adjustable teeth for curly hair.

Topic by vikram_gupta11  


Low friction "bearings"

For several of my projects I required some sort of bearing that would not only allow for a minimised free play but also very low friction.Before you get too exited: This is not a new type of bearing or anthing for heavy duty loads, not even for ongoing use without servicing.I found that even slightly heavier things rotated on makishift bearing far easier if the axle was verticall instead of horizontally.This gave me the idea to try a simple needle-bearing approach.This is how it goes:1. Grind and polish your axle to get a nice needle point - it must be perfectly centered!I prefer to do this with the axle in a fast spinning drill on a fine grinder.The polishing in a simlilar way, but please do not try it with a cloth in your hand on a spinning axle!2. The other part of the bearing is a screw or pin with a punch mark.I grinded and polished a punch for this so it has an angle of 60° and polished it to a mirror finnish.If alignment is of importance then of course the pin/screw must work for this purpose!If in doubt make it spind an use a pencil to get the true center.A drop of sewing machine oil and it spins nice and with very little friction.The key is to adjust the gap(s) between axle and punch mark to next to nothing.You don't want any pressure along the axle as you would "drill" a hole into your mounts.And you don't want it too loose to avoid wobble.I hope it might give you an idea for your next project.

Topic by Downunder35m  


Husqvarna chainsaw carburetor adjustment tool

I just worked on a Husqvarna 142 chainsaw for a friend. Yes, there are openings in the side of the machine so the Low and High carburetor screws can be adjusted, but a special tool is required, or parts need to be removed from the saw so the screw shanks can be grasped with a pair of needle nose pliers. A special tool is svailable for about $6 US. It fits over the longitudinal ridges on the upper part of the screw shank. I discovered the right size of semi-rigid plastic tubing makes an effective adjustment tool. Just cut a length three or four inches long. Push one end onto the desired screw shank and turn to adjust. The tubing is rigid enough that it does not twist, but turns the screw needing adjustment.

Topic by Phil B    |  last reply


Low Voltage High Current power supply

I am going to start off by saying I have no electrical backround, I can solder and am very mechanically inclined. I am wanting to use these as a laser power supply. I have a 24v 50a, a 48v 25a , and am getting a 5v 175a power supplies. I would like to do the voltages and amps adjustable with a potentiometer to go from 0- to their rated output. I see voltage regulators all over but they arent made for high current and usually dont make the current adjustable. How could I do this? Most laser diodes these would be used for are 2.2-3.5 volts.

Question by wby300    |  last reply


Variable, low-RPM DC motor setup?

Hey guys, I'm hoping to build a motorized slider system for my DSLR camera. I'm going to build the slide from scratch and probably attach a motor with a pulley system to move the slide, this should give me the option of having the camera climb the slide if it's on a slight angle. I'm not extremely electronically inclined but I understand I will need a low RPM motor and a PWM unit to adjust the speed. I'm thinking RPM between 0.5 & 10 would be ideal. Could I buy one of these (http://www.aliexpress.com/item/12v-100w-pwm-speed-controller-motor-governor-DC6-15v-STP50n05-wholesale/1663330358.html) add a 12v battery and a 12v DC motor and call it a day? If this is the case, should I be aiming for a 10 RPM motor that I can turn the speed down on? Is a 12v battery/motor likely to give me reasonable torque for dragging a DSLR camera up a moderate incline? Battery life shouldn't be an issue as the longer the use the less RPM I'll need. Any thoughts would be much appreciated.

Question by tig5    |  last reply



how do i make high rise jeans ultra low rise?

Taking down the waist a few inches how would i do that? full instructions please :}

Question by radamanda    |  last reply


How to build a solar panel adjustable? It could be done using light sensors?

I have a model of a swiveling solar panel not too big, with a low price, materials not very difficult to achieve ... Thanks!

Question by Lulon    |  last reply


How might I make a loft bed where the bed height is adjustable?

I want to make a loft type bed for my daughter, with a desk / dressing table underneath. However, she is still quite young, so I dont want the loft bed too high at night. I want to be able to move the bed platform up and down to a high 'out of the way' position for use in the day and a low position for sleeping (sort of  'just above the desk top position') But I obvioulsy need to be able to move the bed up and down on a daily basis, so I need something to achieve this. I am looking at what mechanisms people might think suitable - tracks with linear actuator or gas struts perhaps? with obviously some sort of locking device. Any ideas guys?

Question by ChemicalJasper    |  last reply


I'm trying to use a 555 timer to flash a LED but I want to be able to adjust the speed of the flashing Answered

I'm trying to build a simple circuit using a 555 timer chip Ideally a low power one so I can power it off 2 AAs to flash a LED at a variable speed from rapid flashing to once every few seconds. any help would be appreciated.

Question by joeAMERICA    |  last reply


How do I make a microphone based light organ that can makes christmas lights dance to highs, mids, or lows?

I'm looking for an instructable that gives directions on how to make a light (color?) organ that I can plug christmas, rope, or any other light into and have them dance to either the Highs, mids, or lows of a song. Is it possible to have 3 plugs that can be independently adjusted to listen to highs, mids, or lows? Lastly, is it possible to switch between having the light always on and dim when it "hears" the music, and having the light off and turn on when it "hears" the music?  Where can I find such an instructable?  Thanks! 

Question by chasemassey    |  last reply


Neat Little Lamp

Check out this neat little lamp I found at Lowes. It's got pencil and paper holding "hands", LED bulb "head", and fully adjustable joints. Impulse buys FTW! I was supposed to be looking for a ceiling fan :P An Instructable on how to make one of these would be cool.

Topic by Spl1nt3rC3ll    |  last reply


How to create motor or generator resistance system for exercise machine?

Researching a method to use resistance from a motor or generator for an exercise machine.  There is an axle from which both foot and arm levers extend, so there is rotation, but only about a half turn in each direction, so very low speed, and back and forth.  I have used magnets and eddy current and flywheel from exercise bikes, geared up with a belt.  This works ok, but does not provide enough resitance even when magnets are adjusted very close to flywheel (due to low speed of rotation). I hope to find something already built and available for a similar application, but can locate parts and build it if I understand how.  Resistance must be variable from low to very strong and controllable so user can adjust it.  I have DC motor, and shorting the cord greatly increases the drag, but how do I vary/control it?  Would adding resistance between the wires in the cord increase drag and make it harder to turn?  I have experimented with this and it does not seem to have an impact.  Thanks for your help.

Question by zanimann    |  last reply


How to increase computer output volume without headphone? Answered

I use p5-qplam motherboard.when i connect my 100mw 32ohm headphone,I feel its volume is very low even every volume adjuster is at max. I don,t want to spend too much.How can I obtain more volume?

Question by Suraj Grewal    |  last reply


Is this a good paintball gun?

I am thinking of getting the syndicate misfit paintball gun. Does anyone have one or experience with one. here are the specs: The Misfit is the ONLY marker in its class to operate at low pressure using CO2. Its precision performance and engineering detail make this marker the most powerful at its level on the market today. +2 piece 14" barrel +multi mode electronic grip frame +adjustable rate of fire up to 16 balls per second (BPS) +3 firing modes (semi auto, 3 round burst & full auto) +LED light Display +enhanced volumizer +3/4" gauge +vertical Feed +leak proof valve (US patent 3.553.983) +adjustable double trigger +push button safety +deluxe field strip pin +spring loaded ball detent +vertical adapter +external battery charging port +top & rear cocking +Gloss anodized finish (also available in green to black fade finish) +milled body +standard bottom line adapter +velocity adjuster with lock +adjustable in line regulator +all metal gun no plastic exterior parts!

Question by Thelonelysandwitch    |  last reply


Some tips for digital calipers user

          Do you have a digital caliper, and what do you do when there is some truoble on the display of digital calipers? Now i will share some tips to all of my new friends, and i sincerely hope that they will offer you some help when you needed.           When using the digital calipers for a long, long time, there will be some following troubles:         1. When digital calipers occur to the flashing digits, that means it is in low voltage. So the users should replace the button cell.         2. When there is no display on the digital calipers, maybe it is in low voltage or in poor contact. For the reason of low voltage, the user need to replace the button cell; while for the reason of poor contact, the user need to adjust and clean the battery seat.         3. When the display just shows the fixed digits, it means there is accidental trouble in circuit. So the user should take out the battery and put in back after one minute.

Topic by dignig    |  last reply


Higher powered speakers with lower powered amp or Low powered speakers with higher power amp?

There is a lot of conflicting information on this and I would like to know if my speakers/amp would get damaged. Using 80w speakers and a 50w amp will there be any problems with running on full volume? And if I got a 100w amp with those 80w speakers will there be damage, even if I added a heat sink to the back where the voice coil is? The speakers say 80w max but not really reliable as they are well priced Chinese speakers. Speakers: 80W Audio Sensitivity: 88dB Frequency Range (Hz): 100-20Khz 4 Ohm Amp: Efficiency: 90% Rated output power: 2*50W+100W Working voltage: DC18V to DC24V The maximum output current: 4A Frequency Response: 20Hz-20KHz Can drive a 3-16 ohm speakers In the condition of rated voltage 24V The sub woofer channel at rated voltage 24V state can drive 2-16 ohm sub woofer Bass cut-off frequency independent regulation 20HZ-20KHZ adjustable Very confusing conflicting info online with under rated amps causing clipping and over powered amps frying the speakers. Originally I thought it was only bad to over power the speakers. Any help about what is worse, is appreciated.

Question by bonze77    |  last reply


Smart amplifier design building blocks help? (making an amp w/ auto-volume adjust by controlling gain with running avg)

I am currently working on a simple headphone audio amp that automatically adjusts volume to my preference, regardless of what video I click on when it is plugged into a computer. I am tired of some video's being so quiet that I have to crank up the volume to overdrive to hear it, while other video's blast out sound and burst my eardrums. And of course when watching photonicinduction videos, he often can be hard to hear his voice at really low volume at like 12 at night when everyone is asleep, but then the sparks and hammers come into the picture, it is often too late to crank the volume back down, and thus makes your ears bleed or waking everyone up in the neighborhood! X-(. (Luckily he has included sound warnings, but I am lazy, and will engineer things that do the hard work of adjusting volume for me! :)   ) In a way, I understand that this will minimize the dynamic range, which I suppose hardcore "audiophiles" will go NUTS over me actually WANTING to do that, but none the less, That is what I want. My design currently is just a simple emitter follower with a NPN and PNP transistor is the class AB operation, and to minimize crossover distortion and give a definite gain, I have negative feedback op amp from the output of the totem pole transistor arrangement back to the inputs that feed the base of the low and high side transistor. (obviously, the transistors by themselves are low impedance output, (CV mode) and high impedance input, and have a gain of like 1.) Sorry, no schematics, but you capable of googling it if you want to see what I am describing. As it is, it works fine. HOWEVER, it does not do the automatic volume, or gain control. That is set in stone by a resistor divider network between the feedback and ground (the basic non inverting amp feedback config.) I do not want a fixed gain. I want a electrically adjustable gain. The thing I plan to use to do the automatic adjustment would be a peak detector on the input, which is probably going to be a simple diode and capacitor with a buffer, and a discharge resistor (or constant current drain) across the capacitor to gradually lower the max output, or possibly an integrating op amp that effectively takes a running average. The output of that needs to control GAIN of the primary amplifier, and I want to be able to control the PID of that thing, maybe by tuning the a LCR circuit, or what have you. It is all nice and analog, just the way I like it! :) If ONLY there was some magical (and common) component that I could control the resistance anywhere in the feedback loop, of with a given voltage w/ respect to ground... I was thinking of like a MOSFET, but I would have to deal with the non linearity of the input vs output impedance, which probably changes with respect to everything from the current flowing through the channel, the voltage relative to ground at the source, the temperature, the alignment of the planet's, what mood god is in, etc etc etc. That is too many factors for an open loop control on to model in discrete stuff! And digital potentiometers are out of the question since, well they are digital, I want an elegant simple solution, and the are $$ and difficult to deal with. They have so many requirements that need to be addressed.  I prefer a elegant discrete transistor circuit, but op amps and other basic building blocks are acceptable, (this thing I want to be built over a weekend with with jellybean parts from by junk bin.) if you happen to know of a specific audio chip that does this for me, please mention it, but I will probably not use it, but maybe analyze the internal circuitry and learn how it works.

Question by -max-    |  last reply


What is this??? Answered

I found this in a box of misc. wires yesterday at a thrift store looks like a toy for a computer game maybe. It has a speaker up top and an adjustable microphone at the bottom. I know that speaker and microphone are self explanatory, but I was curious to know what exactly it may have been used with. It has a place in the middle to put in three AA batteries and it has a removable clip to attach it to something. When I put in the batteries it appeared to work or the little red light indicator  came on and the speaker was on with a real low fuzz sound. I have not plugged it into anything yet , I wanted some input first.Thank you in advance to anyone with help.

Question by ViolentaniousA    |  last reply


Sentry Gun and PIR sensors

Hello, I have a question about PIR sensors for a robot I'm making. Most have a digital pin that goes high when movement is detected. The time that this pin stays high for (delay time) is often adjustable by a variable resistor on the sensor. My problem is that I need a sensor with no delay time - the digital pin should go low as soon as movement stops. If anyone could point me in the direction of a pir sensor with no delay time/one with a very short delay time (under 0.5s) I would be grateful. Or possibly, If I were to remove the variable resistor, would that remove the delay time? thanks.

Topic by SentryGunner  


PLZ KINDLY SEND ME EASY CIRCUIT DIAGRAM HOW CAN I MADE A DIGITAL THRMOMETER & HOW I CAN TAKE THESE SIGNAL ON OUTPUT.

RESPECTED PERSONAL , PLZ KINDLY SEND ME EASY CIRCUIT DIAGRAM HOW CAN I MADE A DIGITAL THRMOMETER WITH DRIVING REVERSE & FORWARD 9 TO 12 VOLT DC MOTOR BY THE  ADJUSTMENT OF LOW / HIGHT TEMPERATURE .   OR HOW CAN I TAKE DIGITAL SIGNAL OF THERMOMETER ON AS A OUTPUT TO DRIVE MOTOR IN REVERSE & FORWARD MOVEMENT PLZ KINDLY SEND ME BOTH CIRCUITE WITH ATTACHMENT TO EACH OTHERS. PLEASE HELP ME . MY E-MAIL ID IS : taha_faheem@hotmail.com

Question by TAHA_FAHEEM    |  last reply


555 timeout troubles?

Evening all,  This is most likely a very basic problem but for the life of me I can't find the solution. The project: auto folding wing mirrors (see below) http://www.lexusownersclub.co.uk/forum/index.php?app=core&module;=attach&section;=attach&attach;_id=6108 The problem: for some reason my alarm logic is the opposite way round, most likely due to the removal of my motion sensor due to it tripping my alarm when locked. Now I have modified the circuit shown in the PDF to remove TR2 and R4 so the I/P to the 555 is kept high by the 12v alarm signal. I have a pot between pin 2 and ground so I can adjust the pull down point as the alarm signal only drops to 9.7V and, obviously, the 555 needs logic high or low. So, having adjusted the pull down point, I find that the 5 second timeout, which worked when I first built the circuit as per the PDF, no longer switches the O/P off.  So so what am I doing wrong or is it just best to us a picaxe to do all of this as I code write up the code in half an hour or so. thanks

Question by LED Maestro    |  last reply


Joule robber - a better joule thief....

I had a look at some of our 'ibles for the famous Joule Thief circuit. While checking a few of the creations and checking their performance I noticed a massive flaw: Only LED's with very low power consumptions can be used. After some trial and error I was able to create a slightly modified version that not only lights white and blue 5mm LED's but also the very powerful Cree Led's - the later would require a suitable transistor to handle the load. I only used a salvaged BC556 transistor, so the LED starts working at around 0.5V, brightness is adjustable within certain limits to cater for the battery state. So instead of using a limited circuit that basically just doubles the input voltage with the focus of extreme low power consumption, my circuit is aimed on single cell battery lamps that might need more power. Using a very low voltage transistor with minimal losses would still provide a power source for batteries that are under 0.5V, while using a bigger transistor like Tip142 or 2N3055 and a modified transformer can drive a CFL lamp from two AA batteries, single cell if you don't mind a warm transistor. Biggest improvement however is that I don't use a toroid core, which makes winding so much easier :) I am not too good in drawing circuits and prefer the direct solder method for my prototypes but if there interest I would take the time to make some pics and draw a circuit for an Instructable. But with so many similar circuits already out there I wanted to get some feedback first.

Topic by Downunder35m    |  last reply


Vintage Headphone repair, help needed

I have some vintage Superex Stereophones, model Pro B-VI (with a google search only find an ad in a paper dated 1973 referencing them). They have both a tweeter and a woofer in each ear, and I believe the resistors in the crossovers have gone bad. The high end drops out now and then to pop back in after a short while or after a minor volume adjustment - other than that the volume is crystal clear. Am I right in assuming the resistors could be the issue? The other components in the crossovers are just inductor coils, which are know are for the low pass, so it can't be those. I know instructables isn't a electronics repair forum, but I wasn't too sure of where else I could ask and find knowledgeable people. I love this site. :) I.W.

Topic by incredibleweirdo    |  last reply


Sydney Opera House on wheels!

I live in a semi-rural area.  We are hours from a decent motorway, but hip-deep in caravan parks. Given the UK law that limits trailers to 50mph, I am generally disapproving of anything towed. However, this trailer tent designed by Axel Enthoven is a thing of beauty and luxury. The Opera trailer tent has features including central heating, teak flooring (and a veranda!), ceramic toilet, electrically adjustable twin beds (which can be joined into a double), kitchen sink (of course), onboard water boiler (which supplies a fountain?), fridge and low-energy LED lighting “from awning to floor” (yes there are uplights!). Unfortunately, beauty has a price - €24,000 puts it in the price-range of campers with engines and no restriction to 50mph... Your Suite in Nature via Notcot.

Topic by Kiteman    |  last reply


Arduino capacitive touch sensor help

So I have been messing around with the Arduino Capsense library with the immensely helpful guide; https://www.instructables.com/id/How-To-Use-Touch-Sensors-With-Arduino/  (many thanks to DangerousTim!)   using the code provided, i managed to get a relay to operate with a sensor.  It worked great and I was able to adjust the distance and sensitivity.  But when i tried adding another sensor and relay, it stopped working.  I've been trying to isolate the problem for a while now and have gotten nowhere.  I'm hoping someone can help me, here's the original code for the single sensor and relay; #include #include                                           //change '42' to any desired pin... long time = 0; int state = HIGH; boolean yes; boolean previous = false; int debounce = 200; CapacitiveSensor   cs_4_2 = CapacitiveSensor(4,2);  // To add more sensors... //CapacitiveSensor   cs_4_6 = CapacitiveSensor(4,6);        // 10M resistor between pins 4 & 6, pin 6 is sensor pin, add a wire and or foil //CapacitiveSensor   cs_4_8 = CapacitiveSensor(4,8);        // 10M resistor between pins 4 & 8, pin 8 is sensor pin, add a wire and or foil void setup()                    {    cs_4_2.set_CS_AutocaL_Millis(0xFFFFFFFF);    pinMode(13, OUTPUT);   } void loop()                    {     long total1 =  cs_4_2.capacitiveSensor(30);            if (total1 > 60){yes = true;}     else {yes = false;}            // to toggle the state of state         if(yes == true && previous  == false && millis() - time>debounce){              if(state == LOW){          state = HIGH; }     else state = LOW;     time = millis();     }                     digitalWrite(13, state);            previous = yes;                 delay(10); } and here's the code for the two sensors and relays #include int led = 13;     int led2 = 12;    long time = 0; int state = HIGH; long time2 = 0; int state2 = HIGH; boolean yes; boolean previous = false; boolean yes2; boolean previous2 = false; int debounce = 200; CapacitiveSensor   cs_4_2 = CapacitiveSensor(4,2);        // 10M resistor between pins 4 & 2, pin 2 is sensor pin, add a wire and or foil if desired CapacitiveSensor   cs_5_7 = CapacitiveSensor(4,6);        void setup()                    {    cs_4_2.set_CS_AutocaL_Millis(0xFFFFFFFF);    cs_5_7.set_CS_AutocaL_Millis(0xFFFFFFFF);  //Calibrate the sensor...    pinMode(led, OUTPUT);    pinMode(led2, OUTPUT); } void loop()                    {     int total1 =  cs_4_2.capacitiveSensor(30);     Serial.println(total1);     int total2 =  cs_5_7.capacitiveSensor(30);                     if (total1 > 60){yes = true;}     else {yes = false;}    if (total2 > 60){yes2 = true;}     else {yes2 = false;}           // to toggle the state of state     if(yes == true && previous  == false && millis() - time>debounce){                    if(state == LOW){          state = HIGH;        }        else          state = LOW;          time = millis();      }                          if(yes2 == true && previous2  == false && millis() - time2>debounce){                   if(state2 == LOW){          state2 = HIGH;        }        else          state2 = LOW;            time2 = millis();            }                 digitalWrite(led, state);       previous = yes;       digitalWrite(led2, state2);       previous2 = yes2;                  delay(10); } Any suggestions are always helpful.

Topic by dudes    |  last reply


programmable micro-controller for multi-stage coil gun?

Hey everyone, right now I'm in the early design stages for a large, two coil, coil-gun that I'm going to be building sometime in the next few months ( I need to gather the money for the project lol) Anywho, I'm looking for a programmable micro-controller that I can easily adjust ( I know some programming, mostly C++ and java script) That can send a low voltage signal to two separate thyristors at a certain interval ( probably a few milliseconds apart, but maybe even lower), or not send a signal to one at all, if needed. On a side note, one thing I can't find anywhere, for maximum velocity, should the two coils have the same, or different strength ( aka, should the second give off a stronger magnetic burst then the first, or should they be the same. If anyone knows a better way to do this than using a micro controller, then please feel free to tell me. 

Question by epicbobman52    |  last reply


Arduino Code? Answered

Int redPin = 9; int greenPin = 10; int bluePin = 11; int buzzerPin = 7; int potPin = 1; int sensorPin = 0; long red = 0xFF0000; long green = 0x00FF00; long blue = 0x000080; int band = 10; // adjust for sensitivity void setup() {   pinMode(potPin, INPUT);   pinMode(sensorPin, INPUT);   pinMode(redPin, OUTPUT);   pinMode(greenPin, OUTPUT);   pinMode(bluePin, OUTPUT);   pinMode(buzzerPin, OUTPUT); } void loop() {     int gsr = analogRead(sensorPin);     int pot = analogRead(potPin);     if (gsr > pot + band)     {         setColor(red);         beep();     }     else if (gsr > 16;     int green = (rgb >> 8) & 0xFF;     int blue = rgb & 0xFF;     analogWrite(redPin, red);     analogWrite(greenPin, green);     analogWrite(bluePin, blue); } void beep() {     for (int i=0; i<1000; i++)     {         digitalWrite(buzzerPin, HIGH);         delayMicroseconds(100);         digitalWrite(buzzerPin, LOW);         delayMicroseconds(100);     } } The code does not compile properliy it says steColour was not defined in the scope.Its a lie detector code.

Question by oallaa    |  last reply


automatic switching of street lights by using ldr and relay

 hey me and my friends were ton a project of automatic switching of a street light depending on the brightness in the surroundings. so we decided to use an ldr(light dependent resistor). here in this circuit ldr has low resistance in brightness(only few ohms) and very high resistance in complete  darkness(nearly 1M ohm).so the transistor Q1 becomes on in day times and Q2 becomes off and hence the relay remains in NC(normally closed) state and the lamp will not glow. at night the transistor Q1 becomes OFF and Q2 becomes ON and hence the relay goes to NO(normally open) state and the lamp glows.and the sensitivity of the device can be varied by adjusting the potentiometer  now i just want to know are there any defects in this circuit so can u please help me in knowing the drawbacks and correcting them and i want to know whether i can connect a relay in place of a fuse as shown at bottom

Question by spartans    |  last reply


Stop the light arcade game. Why is my ISR (interrupt Service Routine) not working?

I have written the following code in hopes of running an arcade style game. The idea of the code is that 2 cases will run the first being the lights tracking back and forth before the button has been used to stop them. The second case happens when the button is pressed, and flashes on the light stopped on untill the button is pressed again. Also, a potentiometer is employed to change the speed of the lights. The 4th light is the only red one the one you are trying to "catch" if caught "Winner" is printed... if not "try again" problems with code that i need help  on 1. the ISR isn't functioning 2. How can i have "winner" or "try again" print only once not with every blinking of the light 3. i think in case 2 its only using the case of light 4 even if it is not light 4... why is this? THANKS!! int Button=2; //button assigned to pin 2 just changed because of INT0 havent adjusted lights yet volatile int Buttonstate= LOW; int ledPins[] = { 2,3,4,5,6,7,8,9,10 }; // an array of pin numbers to which LEDs are attached int pinCount = 9; // the number of pins (i.e. the length of the array) int potpin=A1; int potscale=8; int oldpot=0; int var=1; void setup() {   pinMode(Button, INPUT);   pinMode(potpin,INPUT);   attachInterrupt(0,button,RISING);//INT0   Serial.begin(9600);   int thisPin;   // the array elements are numbered from 0 to (pinCount - 1).   // use a for loop to initialize each pin as an output:   for (int thisPin = 0; thisPin < pinCount; thisPin++) {     pinMode(ledPins[thisPin], OUTPUT);     }   } void loop() {   // reads pot for changing speed of the lights   int potvalue = analogRead(potpin);   int difficult= (1023- potvalue)/100;   // print the difficulty if it changes   if (difficult != difficult) {   Serial.print(" difficulty = " );   Serial.println(difficult);   oldpot = potvalue;   }   switch (var)     {     case 1:         //lights incrementing right to left          for (int thisPin = 0; thisPin < pinCount; thisPin++) {           digitalWrite(ledPins[thisPin], HIGH);           delay(potvalue/2);           digitalWrite(ledPins[thisPin], LOW);          }          //lights decrementing left to right         for (int thisPin = pinCount - 1; thisPin >= 0; thisPin--) {           digitalWrite(ledPins[thisPin], HIGH);           delay(potvalue/2);           digitalWrite(ledPins[thisPin], LOW);         }         break;      case 2:        //winner case if stopped on red light         if (int thisPin=4){           Serial.print("Winner!");           digitalWrite(ledPins[thisPin], HIGH);           delay(100);           digitalWrite(ledPins[thisPin], LOW);           delay(100);         }         //loser stopped on some other light         else{           Serial.print("try again");           digitalWrite(ledPins[thisPin],HIGH);           delay (100);           digitalWrite(ledPins[thisPin],LOW);           delay (100);        }         break;   } } //ISR-Button has gone HIGH void button() { //change buttonstate again   Buttonstate=digitalRead(Button);     if (var==1){var==2;}     else if (var==2){var==1;}   }

Question by vandygirl2013    |  last reply


Schematic for sound activated lights for drum kit?

Could anyone develop a schematic for this? A friend of mine plays drums, and would like to install lights inside his drumkit. Mainly the bass drum, but in each tom and the snare too, if possible. I'm thinking a mic'd light organ of some sort. When the drum beats, a light comes on in that drum, with variable intensity, depending intensity of the beat. (soft beat, low light; hard beat, bright light, etc) Does not respond to the beats of the other drums. (selective frequency/pitch or adjustable?) The light punches on, then fades out with approx 1 second duration, rather than just punching out. Uses cool-light, preferably colored, because I'm not sure how a hot light would affect the drums. Plugs in to standard 120v outlet. Anyone feeling creative, please offer a design!! It would be much appreciated. I have intermediate knowledge of circuits and soldering, just little knowledge when it comes to component selection.

Question by tylercard    |  last reply


What sensor is best to use to measure smoke density via Arduino?

I have built a cold-smoker for smoking things like bacon, cheese and seafood. Smoke is produced by burning oak chips in an old fire extinguisher and (using the air supply from a compressor) blown into an old fridge in which the food hangs or is placed on racks. Excess smoke exhausts through a second pipe at the top of the fridge. I log temperatures inside the fridge using an arduino.For the best results the smoke density needs to be low but steady over a period of several hours. I currently control this by hand using a valve on the feed from the compressor. I'm working on controlling this valve automatically using a stepper motor to adjust the increase and decrease the airflow to maintain the correct smoke density.How can I sense the density of the smoke reliably? I need to sense levels of density rather than just its presence. The smoke carries tars so the sensor must be easily cleanable. Any suggestions very welcome!

Question by Henmarsh    |  last reply


Project in mind. Need ideas for simplicity.

I have a project in mind. I have children with a pet cat. I intend to build a charcoal filtering for a catbox/cat tree I am building. I want to use an alarm clock (easy to adjust time if needed) to activate maybe a buzzer and flashing light daily for box cleaning. The fan runs at a low speed constantly at the top of a vent tube to keep the smell controlled.  I want an input to reset the buzzer/flashing light when the drawer with the litter box is opened. I have no idea how to build the circuit. I tested the filter system on a mockup box. It works fine cat doesn't notice the fan. (its 3ft up a 3" piece of PVC). The lack of smell is the reason I'll need a reminder. I could purchase an industrial programmable relay but cost is a huge factor and buying an added power supply etc for control voltage adds up. I have an industrial electrical background and no problem working with small circuitry but have never designed anything so hints and help will be appreciated.

Topic by alienmemebr    |  last reply


Can I change resistance values in laser diode driver circuit to be able to use it with another laser diode?

I have Laser survey units,tens of them, each has IR original laser diode with this specification ((Ith= 17mA, Iop= 31mA, 798nm, Im=1.26mA)). This laser diode is not available any more, I used to use a Sanyo replacement for it DL3144-008S with ((Ith=25mA, Iop=30mA,785nm,Im=2.0mA)). The driver of laser diode is attatched, Iused to change the value of series resistor with photo diode to adjust the output power and it works great. Unfortunately the new LD is also not available now the available one for me is 9GAIA red LD(ADL-65o55TL) with ((Ith=18 to 25 mA,Iop=25 to 35mA,655nm,Im=0.12mA)) the beam is very dim even with current 35mA!!! does it have any relation with monitoring current which is very low in the new one and if it has, if someone can advise me how to change values of the resistance to let the driver work with the new monitoring current, and if it is something else kindly adviseThanks

Question by laserplane    |  last reply


Arduino Uno Synth project - Audio output questions

Hi! I am developing a synth/sampler project based on the Arduino Uno r3. This is my first electronics project ever and because of that reason I have some questions which I can't find a definite answer for on internet. The synth has two function. It has a tone generator using the ToneAC library. With code I have mimicked LFO and VCO functions, using potmeters I can adjust the frequency and LFO speed realtime. The other function is that I can trigger samples stored on a SD card using the TMRpcm library. The device will be used in nightclubs on high end soundsystems and PA. I am afraid I will damage the equipment with my device because I do not send a pure audio (AC?) signal. Currently the flow is like this: PWM output (pin 9, 10) -> voltage divider to 2.5v -> RC Low Pass Filter 15Khz -> LM386 amp with volume control -> mono jack output -> mixing desk -> amplifier -> speakers (the TMRpcm and ToneAC library share the same pin (9), I have fixed this by disabling the TMRpcm when the ToneAC is playing and vice versa. The mono jack is wired as follow. pin 9 goes to plus side of mono jack output, pin 10 to negative side. The TMRpcm pin 9 also needs to go to plus side of mono jack output, and mono jack negative needs to go to ground. Because I disable the ToneAC at that time I consider port 10 grounded because it not generating any sound so there is no signal/voltage running out of it, aka the IO pin is set to LOW) I am hoping that using the voltage divider I am within range of the Audio Line levels of a default mixers Line-IN (like Pioneer, Behringer, etc). The RC Low Pass Filter is used to filter of inaudible frequencies and clean up the sound a bit, the LM386 audio amp is used to amplify the signal and (hopefully) make it a real audio signal. The lowest frequency you can play with the synth is 100hz and the highest frequency is 3100hz. Because I lack a lot of knowledge in this field and because I do not own a oscilloscoop I can't say for sure if my output signal is harmful for the equipment and was hoping to get some guidance on my project on this forum.

Topic by erik404  


(newsletter) Homemade Shampoo, Cryptex, RumbleMouse...

Sign-up for this newsletter: Welcome back! NEW Pocket-Sized Contest - Think small, and win a custom laser-etched Leatherman! Get in the Garden Contest - Enter any Instructable with a gardening theme and win an awesome computer-controlled indoor composting machine from NatureMill! Art of Sound Contest - Share any sound or music-related Instructable, and win an incredible custom hi-fi tower set with subwoofer, monster speakers, and more!! Get the LED Out! Contest - Closed for entries, but open for voting! Vote Now! RGBike POV - Open Project Make Your Own Seed Tapes Homemade Shampoo Double Helix DNA Model with LEDs Simple Sequencer Make an Onigiri (Rice Ball) Adjustable Modular Furniture Non-Slip iPod/phone Stand New contest! Get Started with Arduino Build an Alien Artifact DIY Audio Switch How to Cook with Herbs and Spices Win a cool computer-controlled indoor composter! Win these custom hi-fi speakers! Cryptex Design Audio for an iPhone Game Replace Low Voltage Halogens with LEDs RumbleMouse Sign-up for this newsletter:

Topic by fungus amungus  


Problem driving a stepper motor using the A4988 reprap driver board and an Arduino? Answered

Hi guys I am having a problem driving a stepper motor using the A4988 reprap driver board and an Arduino I have set up the wiring using an example I found online (Diagram attached: A4988 wiring) https://www.youtube.com/watch?v=5CmjB4WF5XA.. However the motor does not seem to turn. The motor I am using is from an old Hitachi printer which I took apart a while back. Printed on it is 0.9A/ph. It has six wires however I am using it as a bipolar stepper by just leaving the center tap of each winding unconnected. I have adjusted the VREF on the A4988 board to insure that the current is limited bellow the 0.9A. To do this I used the data sheet of the A4988. As I wanted to run the motor at full step mode, the A4988 data sheet specifies that the winding current could only reach 70 percent of the current limit. consequently: Current limit = 0.9 * 0.7 = 0.63A Current limit = Vref * 2, Therefor Vref = 0.63/2 = 0.315V or 315mV I have therefor set the current limit using the potentiometer on the A4988 to aprox 315mV Once the wiring was set up, I applied power and measured the Vref to confirm it is still the same and it was. Next I disconnected the Power to both the Arduino and the driver and connected in the stepper motor. I then connected the power and uploaded the following code: // defines pins numbers const int stepPin = 3; const int dirPin = 4; void setup() { // Sets the two pins as Outputs pinMode(stepPin,OUTPUT); pinMode(dirPin,OUTPUT); } void loop() { digitalWrite(dirPin,HIGH); // Enables the motor to move in a particular direction // Makes 200 pulses for making one full cycle rotation for(int x = 0; x < 200; x++) { digitalWrite(stepPin,HIGH); delayMicroseconds(500); digitalWrite(stepPin,LOW); delayMicroseconds(500); } delay(5000); // five second delay digitalWrite(dirPin,LOW); //Changes the rotations direction // Makes 400 pulses for making two full cycle rotation for(int x = 0; x < 400; x++) { digitalWrite(stepPin,HIGH); delayMicroseconds(500); digitalWrite(stepPin,LOW); delayMicroseconds(500); } delay(5000); } Nothing happened... started off with 5 volts on the power supply and ramped it up to aprox 12vs however still nothing happened. I can feel the heat sink heating up on the A4988 which means power was reaching it. I measured the voltages from the Arduino to the A4988 and the power supply to the driver and the voltages matched the input. I started shaking about the power connections to and suddenly the motor made one step, but that was it. So i thought it was a problem with the breadboard. I checked the connections on the breadboard and all where connected. To be safe i decided to use another breadbord. Again nothing happened. I checked the Aarduino using the 28byj48 and UNL203 driver and stepper that came with it and they worked fine. I confirmed the wiring sequences and layout multiple times and they all matched the tutorial I followed. My inital thinking was that the stepper motor was broken, so i disconnected it and tried running it using the power supple (5V) by connecting and disconnecting each coil in manually one by one, and it turned one step at a time, which meant that the stepper was working. Finally i decided to see if current was reaching the stepper, I therefore connected the Altimeter in series with one of the coils and it did not read any current, which meant that current was not reaching the coils. Now I am unsure what to do, or what has gone wrong. The vref still reads aprox 310 - 320 mV, this makes me assume that driver is not fried. I do have another A4988 driver however I started working on that one and now the Vref does not go above 62mV so I'm guessing that it is burnt, however the second one reads fine. I have tried using the enable button with the following code (Attached; A4988 wiring 2) however it still didnt' make in difference. The following code is what i used for when I set the enabled to low (Note that the pin numbers have been changed) int Index; void setup() { pinMode(4, OUTPUT); //Enable pinMode(2, OUTPUT); //Step pinMode(3, OUTPUT); //Direction digitalWrite(4,LOW); } void loop() { digitalWrite(3,HIGH); for(Index = 0; Index < 2000; Index++) { digitalWrite(2,HIGH); delayMicroseconds(500); digitalWrite(2,LOW); delayMicroseconds(500); } delay(1000); digitalWrite(3,LOW); for(Index = 0; Index < 2000; Index++) { digitalWrite(2,HIGH); delayMicroseconds(500); digitalWrite(2,LOW); delayMicroseconds(500); } delay(1000); } Why did the motors initially step (only one step upon each shake) when I shook the power supply leads? I am afraid to try that again as I think this is what damaged the first driver I was using. And why is there no current reaching the coils? I would really appreciate an opinion on this issue as I have no idea what to do Many thanks for you time. Adnan

Question by k1228438    |  last reply


Can Someone Modify an Arduino Sketch For Me? Answered

I recently got into Arduino, and my first long term project is an autonomous roaming robot. Now, I've been in electronics for a while, so the actual building of the thing was not a problem....but the programming is. I've found a couple examples of codes online, but they all use Sharp IR sensors, whereas I have a Ping))) Ultrasonic sensor. I was wondering if there were any Arduino experts out there that could modify a sketch that I found to only use the Ping))) instead of the IR sensor(s). This sketch actually uses both, and would be perfect if the Ping))) was used in place of the IR sensors, rather than with them. If anybody could modify the sketch below to do as I said, your help would be greatly appreciated. Thanks. Code: int micVal; int cdsVal; int irLval;  // Left IR int irCval;  // Center IR int irRval;  // Right IR int i;   // Generic Counter int x;  // Generic Counter int PLval;  // Pulse Width for Left Servo int PRval;  // Pulse Width for Right Servo int cntr;  // Generic Counter Used for Determining amt. of Object Detections int counter; // Generic Counter int clrpth;  // amt. of Milliseconds Of Unobstructed Path int objdet;  // Time an Object was Detected int task;  // Routine to Follow for Clearest Path int pwm;  // Pulse Width for Pan Servo boolean add;  // Whether to Increment or Decrement PW Value for Pan Servo int distance;  // Distance to Object Detected via Ultrasonic Ranger int oldDistance;  // Previous Distance Value Read from Ultrasonic Ranger float scale = 1.9866666666666666666666666666667;  // *Not Currently Used* int LeftPin = 6;  // Left Servo int RightPin = 9;  // Right Servo int PiezoPin = 11;  // Piezo int PingServoPin = 5;  // Pan Servo int irLPin = 0;            // Analog 0; Left IR int irCPin = 1;            // Analog 1; Center IR int irRPin = 2;            // Analog 2; Right IR int ultraSoundSignal = 7; // Ultrasound signal pin int val = 0;              // Used for Ultrasonic Ranger int ultrasoundValue = 0;  // Raw Distance Val int oldUltrasoundValue;  // *Not used* int pulseCount;        // Generic Counter int timecount = 0; // Echo counter int ledPin = 13; // LED connected to digital pin 13 #define BAUD 9600 #define CmConstant 1/29.034 void setup() {   Serial.begin(9600);   pinMode(PiezoPin, OUTPUT);   pinMode(ledPin, OUTPUT);   pinMode(LeftPin, OUTPUT);   pinMode(RightPin, OUTPUT);   pinMode(PingServoPin, OUTPUT);   pinMode(irLPin, INPUT);   pinMode(irCPin, INPUT);   pinMode(irRPin, INPUT);   for(i = 0; i < 500; i++) {     digitalWrite(PiezoPin, HIGH);     delayMicroseconds(1000);     digitalWrite(PiezoPin, LOW);     delayMicroseconds(1000);   }   for(i = 0; i < 20; i++) {   digitalWrite(PingServoPin, HIGH);   delayMicroseconds(655 * 2);   digitalWrite(PingServoPin, LOW);   delay(20);   }   ultrasoundValue = 600;   i = 0; } void loop() {   //Scan();   Look();   Go(); } void Look() {   irLval = analogRead(irLPin);   irCval = analogRead(irCPin);   irRval = analogRead(irRPin);   //if(counter > 10) {     //counter = 0;     //readPing();   //}   if(irLval > 200) {     PLval = 820;     PRval = 850;     x = 5;     cntr = cntr + 1;     clrpth = 0;     objdet = millis();   }   else if(irCval > 200) {     PLval = 820;     PRval = 850;     x = 10;     cntr = cntr + 1;     clrpth = 0;     objdet = millis();   }   else if(irRval > 200) {     PLval = 620;     PRval = 650;     x = 5;     cntr = cntr + 1;     clrpth = 0;     objdet = millis();   }   else {     x = 1;     PLval = 620;     PRval = 850;     counter = counter + 1;     clrpth = (millis() - objdet);     if(add == true) {       pwm = pwm + 50;     }     else if(add == false) {       pwm = pwm - 50;     }     if(pwm < 400) {       pwm = 400;       add = true;     }     if(pwm > 950) {       pwm = 950;       add = false;     }     digitalWrite(PingServoPin, HIGH);     delayMicroseconds(pwm * 2);     digitalWrite(PingServoPin, LOW);     delay(20);     readPing();     if(ultrasoundValue < 500) {       cntr = cntr + 1;       switch(pwm) {         case 400:           x = 7;           PLval = 650;           PRval = 650;           Go();           break;         case 500:           x = 10;           PLval = 650;           PRval = 650;           Go();           break;         case 600:           x = 14;           PLval = 850;           PRval = 850;           Go();           break;         case 700:           x = 10;           PLval = 850;           PRval = 850;           Go();           break;         case 950:           x = 7;           PLval = 850;           PRval = 850;           Go();           break;       }     }   }   //Serial.print("clrpth: ");   //Serial.println(clrpth);   //Serial.print("objdet: ");   //Serial.println(objdet);   //Serial.print("cntr: ");   //Serial.println(cntr);   if(cntr > 25 && clrpth < 2000) {     clrpth = 0;     cntr = 0;     Scan();   } } void Go() {   for(i = 0; i < x; i++) {     digitalWrite(LeftPin, HIGH);     delayMicroseconds(PLval * 2);     digitalWrite(LeftPin, LOW);     digitalWrite(RightPin, HIGH);     delayMicroseconds(PRval * 2);     digitalWrite(RightPin, LOW);     delay(20);   } } void readPing() {  // Get Distance from Ultrasonic Ranger timecount = 0; val = 0; pinMode(ultraSoundSignal, OUTPUT); // Switch signalpin to output /* Send low-high-low pulse to activate the trigger pulse of the sensor * ------------------------------------------------------------------- */ digitalWrite(ultraSoundSignal, LOW); // Send low pulse delayMicroseconds(2); // Wait for 2 microseconds digitalWrite(ultraSoundSignal, HIGH); // Send high pulse delayMicroseconds(5); // Wait for 5 microseconds digitalWrite(ultraSoundSignal, LOW); // Holdoff /* Listening for echo pulse * ------------------------------------------------------------------- */ pinMode(ultraSoundSignal, INPUT); // Switch signalpin to input val = digitalRead(ultraSoundSignal); // Append signal value to val while(val == LOW) { // Loop until pin reads a high value   val = digitalRead(ultraSoundSignal); } while(val == HIGH) { // Loop until pin reads a high value   val = digitalRead(ultraSoundSignal);   timecount = timecount +1;            // Count echo pulse time } /* Writing out values to the serial port * ------------------------------------------------------------------- */ ultrasoundValue = timecount; // Append echo pulse time to ultrasoundValue //serialWrite('A'); // Example identifier for the sensor //printInteger(ultrasoundValue); //serialWrite(10); //serialWrite(13); /* Lite up LED if any value is passed by the echo pulse * ------------------------------------------------------------------- */ if(timecount > 0){   digitalWrite(ledPin, HIGH); } } void Scan() {   // Scan for the Clearest Path   oldDistance = 30;   task = 0;   for(i = 1; i < 5; i++) {     switch(i) {       case 1:         //Serial.println("Pos. 1");         pwm = 1125;    ///  incr. by 100 from 1085         break;       case 2:         //Serial.println("Pos. 2");         pwm = 850; //// increased by 100 from 850         break;       case 3:         //Serial.println("Pos. 3");         pwm = 400;         break;       case 4:         //Serial.println("Pos. 4");         pwm = 235;         break;     }     for(pulseCount = 0; pulseCount < 20; pulseCount++) {  // Adjust Pan Servo and Read USR       digitalWrite(PingServoPin, HIGH);       delayMicroseconds(pwm * 2);       digitalWrite(PingServoPin, LOW);       readPing();       delay(20);     }     distance = ((float)ultrasoundValue * CmConstant);   // Calculate Distance in Cm     if(distance > oldDistance) {  // If the Newest distance is longer, replace previous reading with it       oldDistance = distance;       task = i;   // Set task equal to Pan Servo Position     }   }   //Serial.print("Task: ");   //Serial.println(task);   //Serial.print("distance: ");   //Serial.println(distance);   //Serial.print("oldDistance: ");   //Serial.println(oldDistance);   distance = 50;  // Prevents Scan from Looping   switch(task) {   // Determine which task should be carried out     case 0:  // Center was clearest       x = 28;       PLval = (850);       PRval = (850);       Go();       break;     case 1:  // 90 degrees Left was Clearest       x = 14;       PLval = (650);       PRval = (650);       Go();       break;     case 2:  // 45 degrees left       x = 7;       PLval = (650);       PRval = (650);       Go();       break;     case 3:  // 45 degrees right       x = 7;       PLval = (850);       PRval = (850);       Go();       break;     case 4:  // 90 degrees right       x = 14;       PLval = (850);       PRval = (850);       Go();       break;   } }    

Question by punkhead58    |  last reply


Arduino lag problem Answered

I'm trying to convert my Arduino into a square wave generator to test various flybacks. The problem is the functions seem to lag the process down, I've separated the generator() sequence from the rest of the program to isolate it from lags, but executing the analogread() the while() and digitalWrite() seem to be enough to limit the whole thing to 6kHz when set to 20kHz (50 uS period). void generator(){ while(analogRead(0)>1000){         //when a button is pressed it returns to settings mode digitalWrite(out, HIGH); delayMicroseconds(period); digitalWrite(out, LOW); delayMicroseconds(period); } } Removing analogread() and putting a silly constant like (n==0) it goes up to 16kHz, it's quite remarkable, but doing that there's no way of using the buttons to adjust the settings while running. I don't know if I can substiitute analogRead since all the buttons of the display have different analog values and are connected to A0. Is there a way to remove this lags? I know there's a lot of optimization to be done even at a very basic level, but I don't know how or where to start. Ideally I just want it to work from 1 to 50kHz. Here's the complete program, as far as I know, all the lags occur inside the generator() function. Thanks for your time!!

Question by Victor805    |  last reply


3D or correctly 2.5D engravings on wood with a CO2 laser

Due a lack of correct forum sections I just post in the tech department, hoping the right people will find it ;) I did some tests with my CO2 laser cutter to find out how good or bad it works for 2.5D engravings. Turns out not too bad really. But during those tests I often noticed that I have areas where the wood is burnt while in areas with other power levels the wood is vaporised without charring, looks totally clean. So of course this meant further investigation on the topic but to my surprise my Google skills seem to get rusty as I could not find anything of use. As I am still planning to do a full Instructable on the topic of 2.5D engraving it was time to do more detailed tests myself. My machine uses an Arduino Mega as the controller, running on a modified MarlinKimbra release, so I had no problem adjusting all required parameters. Here are some of my findings so far: Once the power levels are high enough to do real damage to wood instead of just darkening it, there are levels that just vaporise the wood. I did not test the full power range but there seem to be several "sweet spots" for the power, above and below the wood will be burnt instead of a clean vaporising. Next step was to check this behaviour with changing PWM frewunecies for the laser firing. Started with a know power level that vaporises and adjusted only the PWM frequency. Lowering the frequency soon caused charring, increasing the frequency had very little effect. Next was a lower power level that with the original PWM frequency would charr the wood. Here lowering the frequency caused more charring, at quite low frequencies to the point that the kerf suffered massively. Increasing the frequency again allowed to find a sweet spot where the wood would vaporise rather than burn. So I am wondering if anyone else has done tests in this regard or knows of any links with more info?

Topic by Downunder35m    |  last reply


Switching to LED lights for your car head lights - what you should know about it!

With LED technology getting cheaper and better almost weekly now it seems to make sense to use them in your old car.People who did it and post about it make the decisions even easier.I mean who wouldn't want to switch from pale yellow candle light to these bright white litghts showing you all in great detail?Problem is the firstly the legal side of things.Many countries now allow the use of LED replacements for many older cars - within limits.Where and if allowed it means you need to use LED systems that a compliant with your local road authorities and regulations.In a lot of countries though it is still not legal to replace incandescent head lights with LED ones.Why is this?If you read this after changing over already you will have noticed a destinct difference between the two types of "globes".The filament is very compact and in a H4 lamp the reflector is quite small and perfectly positioned as well.In comparison to (mostly the non-legal) LED replacements the light emitting surface is flat and usually a lot bigger than the filament.This means the light output and pattern changes as the reflector of your lamp is not designed to work with LED's and their bigger area of light surface.Being flat also means the LED can not really produce the same amount of light in LUX to the sides as compared to directly above.Most LED lamps compensate this with an added reflector in the front area.So we have two major problems:Not really enough light going sideways while too much light goes up and down in the LED system.Too much stray light due to the bigger surface are that puts out the light.Combined they result in light going into areas where it should not go, or not go at this level of brightness.The often used statement that now even highway signs are easy to read at night on low beam clearly highlights this problem.There is a good reason your head lamps should not shine upwards ;)What can be done to allow for the use of LED lamps in old cars?If not too old than your car already has H1/H7 lamps and indiviual for fog, low- and high- beam.For those it is now quite easy to get road legal LED replacements.Not so much though for the really old H4 systems with high- and low- beam in one lamp.Don't be fooled by your local auto shop though!Just because they might sell a lot of HID and LED lmaps does not mean what is on display for sale is actually road legal.If it does not state the corresponding certifications for your country/state than you can rest assured a cop on a bad day will have field day (or night) with you sooner or later.As said, in many countries there are now tested and legal option available.Their main difference to the cheap and uncertified ones is not their higher price alone.In comparison their more powerful LED's result in much smaller COBS -the LED strip giving the light.Reducing glare and providing a much closer match to the incanscent lamps.Why is it so hard to find a common ground and provide proper LED replacement systems?You might as well ask why you can buy a $20 amplifier or a $5.000 amplifier....When the first cars came out with LED lamps China saw the potential and provided all sorts of headlight lamps with LED's in them.Quickly they not only made it to the international markets but also gained interest for basically everyone wanting more light.Regulations were non existent back then...Even today it is next to impossible to actually provide proper numbers in terms of lumen, LUX or general brightness.What a LED provides can be quite different from what leaves the head lights.Old standards only refer to Watt, so it is no problem to find a cheap LED system that provides what a 100W lamp would get you at less than 30W on the input side...And the light color is not really specified at all in most countires.France required a yellowish light back in the day.A blue tint in your head lights was no problem with Xenon lights, so LED systems now go as high 7000 Kelvin, or close to a blueish light and as low as 3000 Kelvin or what is coming from incandescent lights.You see, finding a common ground is already hard just with the light output and color alone.There is only one real test that even today defines whether or not a head light needs adjustment or in case of LED replacements makes them illegal.The good old white wall with the markers, lines and distance mark on the floor.If you compare a properly adjusted head light on these test walls you get a very destinct pattern of light to see.Clear cut off's, brightly illuminated areas within the fields and lines and less bright areas in the outer regions - again still defined by the marks on the wall.Swapping to various types of LED replacements should provide the same patterns and brightness levels.In reality though almost all of them will only give you a very bright and undefined big area on the wall.No more dark areas with clear cut off to the bright middle section, even the formerly shadowish side areas are now well lit up.Great for you behind the wheel, bad for everyone coming the other direction, especially when wet and raining.Some people in the colder parts of the world will now what I mean when I say that some LED system will only give you good visibility when it snows if you turn them off ;)How to check for yourself if your new LED lights are any good for other people on the road?I assume you did the right thing and had your headlights checked and if required adjusted before actually putting LED lights in!Nothing is worse than trying to get more light if said lights are adjusted to point everywhere except the road.With your old light still in park in front on a straight wall on level ground, like your garage or any other wall you find.Park at a nice distance to get a clean pattern on the wall that is not too big.5 to 10 meters away should do fine.Use some painters tape or similar to mark out your desgined light pattern on the wall.Don't be too fancy, just some tape to indicate where bright light turn into way less on the wall and a few strips to indicate the cut off lines where patterns of brightness change on the wall.Leave the car where it is and put your new LED lights in.Check for yourself by how much the areas differ now.Anything above your marked cut off lines means you are blinding other drivers ahead of you.Anything way brighter than before on the sides could mean you also blind oncoming traffic on the other side of the road or freeway.A pale and low light level in these areas is not too bad and can be acceptable.Anything that clearly illuminates those formerly dark areas however should not be used on the roads.Another check is to try at what distance your old low- and high- beam start to become a bit too birght too directly look in to when you stand in front of your car during a really dark night.Look somwhere drak and move closer until you reach the discomfort zone.With your LED lights you should be able to get as close as before ...

Topic by Downunder35m  


Wood Converted SWB Recumbent Bike of Awesome!

This is a project coming soon... But I'm so excited I have to share... I'm beside myself in excitement, in fact.All that's left to finish the project is:1. Recondition a bit more chain and add it on2. Add idlers and get my chain line in order3. Cut excess wood and make a SeatBut after I assembled a crank into some 2x4's - and had to step back and laugh. I've seen it before, in person at the maker faire. But to do it myself and see how easy/simple it is... Ha!So I cobbled that together - made a pseudo tie fighter handle bar from some scrap PVC and two Tees... And rode off into the sunset... Until the chain derailed - and then I realized I couldn't make appreciable low speed turns due to chain routing... Both problems can be fixed with an idler - a solution I've yet to install due to Kinematics homework having a due date of tomorrow.So yeah, this is something I've always wanted to do. And I'm totally happy I did it (and happy I bought those cheap bikes at auction last year :p). AND, the front boom is modular. I intend on making it, and have accommodated for, adjustable. So I can go for more incline and a more aggressive seat position. (mind you, this is a single speed :p).Okay, I'm done venting -- feedback?

Topic by trebuchet03    |  last reply


Light Socket Extension help

Can you help me find a safe way to build a cheaper version of this: http://reviews.lowes.com/0534/3125483/reviews.htm?   Here's my situation: I want to convert double-lamped can lights into adjustable spotlights without making any permanent changes other than unscrewing a lightbulb and replacing it with something else.  It needs to be able to go back to a lightbulb very easily.  The cans stick out from the wall and each socket is oriented vertically, so one points up and one points down, effectively washing the wall up and down with light.  The wall of 8 or so are wired so the tops are all on one circuit and the bottoms are all on another circuit. The item from Lowe's works OK, but is $17 and more flexible than I need.  Here's what I started to put together:   At the top is a 100W Par38 spot light, screwed into a single outdoor metal lampholder.  That is attached to a 1/2" pipe (PVC or metal), about 12" long.  Now, at the bottom of the pipe, it needs to screw in to the socket to get power.  I either need to get an E27 lamp base onto that pipe, or use a two-blade outlet adapter that screws in, and get a two-blade plug that is rigidly fixed to the pipe.   Is there anyway to do this that the NEC would smile at?  Absent of that, a way that is still safe and secure, and safely removeable without changing the existing light socket arrangement?

Topic by kpatrick2    |  last reply


How to build a wireless switch to control a projector lift and electric projector screen!?

This is for a home theatre  setup. The projector is installed on a motorized lift that hangs in the ceiling. The screen is motorized. They are both 110v AC motors, and they both have seperate up / down leads to control the respective operation. The screen motor is 110v 0.7 amp and the projector lift is 110v 0.8 amp. The screen takes approx. 20 seconds to lower and has no apparent calibration to stop at any particular point (I would like the controller to be able to have this capability). The lift motor has a 'up' stop and a 'down' stop adjustment that cuts power on its own when it reachs these points so the controller just has to provide power for the length of time it takes the motor to get there which is about 12 seconds. Both devices have optional add-on hardware to make them infrared controllable but it costs approx $400 each to go that route. My hope is that I can control them with my universal remote along with having a manually controlled switch in case of remote failure. I want to build this as my first project for contribution to Instructables and the Home Theatre community. Is this do-able for less than $50? Please help. Thank you all for your help in advance.

Question by timmot    |  last reply


Eyeclops night vision 2 review

              I haven't used the eyeclops night vision 1, so I can't make any comparisons. From the photographs, you can see two sets of lights on either side and a ring of leds around the camera lens. When in low power or "stealth" mode, only the lights on the sides are on. In the dark, the glow very dimly, you have to be 3 feet or less to see  them glow and it's still very dim. When in long range mode, the lights on the sides turn off, replaced by the circle of lights in the middle. These are clearly visible at close range, even in daytime, although still with less intensity as a red led. The knob toward the eyepiece is for adjustment of eye. I don't see what it does. The knob on the end near the camera adjusts focus. Seeing things at long range clearly and close range clearly require different adjustments. It's real infrared technology. You can switch between "military" and "spy" The difference between "military" and "spy isn't much. One of them is normal, infrared vision, and the other applies a green layer, making it seem like the view from COD. The 6 knobs along the middle don't do anything.  It uses 7.5 volts using 5 AA batteries. There there is only one LCD, despite it claiming dual LCD technology. The skirt on the eyepiece is detachable. The strap feels pretty cheap, I plan on making it into a head light sort of thing later with paracord or elastics. Objects appear closer and you have no peripheral vision though. The latter problem is something all night vision goggles have. Overall, it's not a bad deal for a $50 toy. The most annyoing thing is that the dials are a bit loose, so running or shaking them makes a rattling sound, giving away your position if you were doing covert sneaking around or playing a prank.        This is useful for scanning an area in the dark without revealing your location. It's also useful for night spying. What this toy cannot do is read words or anything in detail the size of words. Although navigation is possible, the lack or peripheral vision is a problem. Possible Mods: Add an airsoft or rc car battery to replace the 5 AA batteries. The half near the eye piece can be cut off I think. You would have to add a new compartment for the batteries though and the light from the LCD would leak out. I would add a strap of two so you can use it hands free. I would also attach a smal telescope or lens backward so objects appear normal distance. The peripheral vision problem could hypothetically be solved the same way people make DIY fisheye lenses. Extra infrared LEDs flashlights and other lights could be added around a house, allowing you to cover up the lights, not exposing your position. Another idea is infrared led throwies. They would function like NATO infrared glow sticks, allowing people to track a certain target or where to fire.

Topic by starwing123    |  last reply


My iRobot Create Idea...

My iRobot Create Challenge idea is this:Have you ever woken up in the middle of the night and needed to use the restroom or get a glass of water?You don't want to turn on the lights because you don't want to deal with the brightness and waiting for your eyes to adjust. At the same time, you can't see where you're going, and you don't want to run into things, or worse, stub your toes on some harsh corner. The solution? Have a little guide robot. Built on the iCreate platform, the Nightguide (as I call it) will be able to record a path from your bedside to the kitchen, the bathroom, or anywhere you might like.When you wake up, you simply press a button on the robot to select a destination. the robot turns on low-level lights towards the ground and guides you quickly to your destination. Once it's reached the destination, it stops and awaits orders. When you're ready to go back to bed, you press a button and it leads you safely back to bed.What happens if it runs into something?Should the robot run into something while it's leading you, it stops, and increases the light it's providing to give you a view of what's in the way. Move it out of the way, and a sensor tells the robot it's a clear path ahead, you continue to your destination unimpeded. The direction and distance traveled by the robot would be judged by internal metering. Perhaps a starting point and stopping point could be set using a similar device to the virtual wall units utilized by the Roomba.

Topic by aarone    |  last reply


Heating Control

I have been thinking for some years now that I would like to have finer control over my central heating. The problem Now we are older we feel the cold more so in winter the heating is on all the time. This means that we have to keep altering the thermostat on each radiator at different times of the day or just leave them and so waste energy. One method means wasting energy but the other means rooms will be colder than we want initially.   The system and what i have We have a combination boiler which has a digital timer and also on the panel are temperature controls for hot water and radiator temperature. Each radiator has a thermostatic valve so each room can have it's temperature set independently. I have a computer which runs 24/7 and also a bit whacker which I can control via python code and electronics has been a hobby for over 50 years My idea I would like to have some system which would allow me to adjust each room temperature via computer control.   Possible solutions Solution 1 Fit a stepper motor to each thermostatic valve to adjust it at different times of the day/night. This would allow precise control but would be quite expensive to set up. Solution 2 Fit a small structure round each valve with a filament bulb or resistance wire in the bottom so that when power is applied to it then the temperature around the valve will rise and so the valve will close or, at least partially close. I think this would be much cheaper to implement but would have the small on-going cost of using power to the bulbs whenever the room temperature needs to be cooler that it would normally be. My initial plan Build a small structure around one of the valves with a low voltage bulb in it. It would have vents at top and bottom and so air would circulate. I have a portable digital thermometer so i could gather information and try different bulbs to see how much power would be needed and therefore what the on-going cost would be. Also try various shapes of structure to see what the effect would be.   So guys what do you think?

Topic by buteman    |  last reply