About four years ago I bought this robot voice kit for a halloween costume: http://www.kemo-electronic.de/en/Hobby-School/B107-Robot-voice.php (the scematics are near the bottom of the data sheet) I never finished it and now that I put it together it's not working. The signal goes through to the amplifier, but without the modulating happening. Does anyone know what the problem could be, or if there is a way to narrow it down without desoldering and testing the components individually? Thanks

I already posted a question about this and I got a lot of suggestions, close to 10 I believe, and all of them did not work. the last time it was on a breadboard so I figured that was the problem. I soldered it onto a neat PCB from radioshack now, but it doesnt even turn on. it is a TPA6021A4 amplifier I (attempted) and on the breadboard it had alot of distortion so I figured it was the breadboard. the amplifier and the L7805 powering it, heats up (although on the breadboard the L7805 heated up anyways but that was connected to a 12v wall wart.) and Ive never seen an L7805 heat up when powered by a 9v battery. Im using a 3w speaker because it is the smallest I have. Im not worried about any distortion I may or may not get I just want it to turn on! this question is getting a little repetitive (posted 3 times now on instructables and 7+ on other places) so I think if I dont find the answer im giving up. DISCLAIMER: this will probably be the worst solder job you have ever seen. If thats the problem please tell me, although 555 timers work just fine. Heres the datasheet:  http://pdf1.alldatasheet.com/datasheet-pdf/view/126743/TI/TPA6021A4.html

We had a problem troubleshooting our project "Counter"? We had set it to count to 0 to 9. But the only output we get is 2 and 3. I would like to ask, what would be the possible errors due to the outputs. Thank you in advance. We really appreciate your answer.

Hey everyone, I use EL Wires to make small neon signs and I've never had any problems with them until I started shipping them places. I have no idea how to fix these things and one of my customers told me the wire is detached from the transformer. Is this fixable?

Ok, so my back speakers of my car aren't working properly... they were working good for a while but aren't as of today... I brought both of them inside and connected them to a household stereo and they both work perfectly in that scenario but one works a lot better than the other in the car. speaker A works well when it is place on either the driver side or the passenger side, speaker B sounds weak and tinny when on either the driver side or the passenger side... Please help me out, i've been racking my brain trying to figure out why they arent working correctly in my car when they play perfectly in my house... and they are car speakers not house speakers

Hello there people of the internets, I'm an electronics newb, hoping someone can help me. I'm trying to trigger a 1.5-3 volt DC motor using a PIR sensor, without using a microcontroller.   I have the PIR sensor's output connected to an npn transmitter which triggers a 5v spdt relay to switch on the motor.  When testing the circuit with an LED, it works perfectly, turning the LED on when motion is detected.   When I swap the LED for the motor, the relay turns on the motor repeatedly every 6 seconds no matter whether there is motion or not. (it also may have killed the relay after about a minute or two) I tried a different circuit, using a transistor as a switch instead of a relay, which also works perfectly with an LED, but when the motor is connected instead, again the motor is turned on every 6 seconds without a care for the PIR output. What could I be doing wrong here?  I'm assuming that perhaps it has something to do with kickback from the motor...maybe? Anybody have any advice?  (Remember, no microcontroller!  As much as I'd love to try my hand at using arduino or the like, I can't afford to use a microcontroller for this particular project.)

Hi- First on an unrelated note, does anyone besides me see "A fatal, non-recoverable error has occurred" over on the Makezine forums when you try to sign in? I've been getting that for weeks! Anyway... I'm working on a variable power supply that uses a 317 to regulate the 18 volts coming from a laptop switching supply. There are two 5k 10-turn (for precision) pots with a switch so that you can have two "preset" voltages and switch between the two of them at will. There's a single output. There's also a little lamp (I used a micro mini 12v lamp instead of an LED because that's what I had) that goes on above the pot that's currently switched in. The circuit I built (schematic is below) seems to work more or less fine. 'cept there's two strange issues: First, although the pots are linear (not sure if that would make the difference or not), they seem to "flatten out" toward their upper range. The first six turns gets you from 1.2 to about 16.5 volts. Then the last four turns either don't change anything or they do so in _very_ fine increments so that you only get from 16.5 to just over 17 volts. That's in four whole turns of the knob. This happens for both pots. The second stange thing is that turning the non-activated pot will affect the current voltage. When you increase the resistance (turn the knob to the right), the voltage level actually drops! Conversely, turning it to the left will increase the voltage. Remember, this is the switched-off pot. The switched-on pot works as it should (barring the mentioned weirdnesses). It looks like how much the voltage changes depends on how many turns you've given the activated pot. I suspect this has to do with me using a SPDT switch instead of a DPDT and maybe some voltage / current bleeding through the lamps and into the adjust pin, or something. But I ca/n't figure out why the switched-off pot would do anything. Anyway, take a look at the schematic. Is there anything I've done wrong that I'm missing? Should I, um, switch (*cough*) to a DPDT switch (something like the second schematic)? I used the SPDT cuz that's what I had. Anyy help is appreciated, Thanks!

I recently installed a Chanxan CW 1610T Laser Cutting Machine with two 95W CO2 laser tubes. Everything works including the cooling system, pumping system and the fan. I turned on the machine and turned on the two lasers. The thing is when I press the Pulse button on the control panel, none of the laser tubes fires. I want to adjust the optical path and I cant do that if the Pulse button has no response. When the machine is ON, the ammeters show a 0 reading and there is no deflection. I thought it was a Laser power problem so I removed the data cables on the laser power box and when I press the test button on the box, the lasers fire beams. So help me out and suggest if its a setting I have missed or something else cause the machine is preventing production to start.

The music that I download from my computer and iTunes to my iPod disappers from my iPod when I connect it to the  computer. Is there a way to keep that from happening?

I need to submit it this month . i am using it for a bipedal robot.can anybody recommend me troubleshooting steps.it was working well before and the cable also works.

I published my instructable two days ago and it is still not showing... What should I do? By the way it says published on my account.

Hello,i need help with the site,i cant access my draft instructables or my collection,i am a noob to the site and i need help

We are trying to build the Tesla Radio for a science fair and can't get any noise from it.  Is there any other photos that we can see to check our connections?  The diode is getting no reaction.  We read that we have to hit it from a specific direction but none seem to work.  Any suggestions?

It turns on, heats up for about 1 to 10 minutes, then click, turns off.  What can cause this?  I usually unscrew the light bulb so it does NOT come on during the cycle, I like to sit in the dark and sweat!  When I screw lightbulb to turn on, unit immediately clicks off. I have been having some panel problems where the time keypad or the temperature keypad will not respond as well.

 I got a oder of donated computers a while back, and one of them was a VAIO laptop (YES, a VAIO!!). Its one of the big ones. But anyway, its missing a CD Drive, and the HardDrive. I replaced the RAM and checked everything else I checked. It will power on, but the processor wont put out any heat, and the screen wont turn on. I swapped processors on it for another one, a intel vs. the INTEL Portable it had. The power and battery is working fine, as well as the RAM, and processor. I'm just stumped as of now on what's wrong. I haven't worked with Laptops much, mostly Desktops (I have 4 custom from scratch sitting in the room now). Any ideas Instructables? You're the kind of people I like. That and Yahoo Answers deleted my question...

Hi I recently bought a cheap WTV020M01 (WTV020SD) sound module from china. i know you get what you pay for but i cant really afford to spend big on that kind of electronics or else i would have. Any ways my problems is i have wired up the component as instructed, loaded up the audio files as per instruction on the micro SD card and connected it to power and hit the play pin. And NOTHING happened. i then tested to see if it was getting power and yes the power was fine. After being frustrated i tried moving around the power connector and discovered that if i placed the power in the reset pin the module lit up as if it was working and all the buttons worked but still no sound. i am not sure that as its a cheap component its a dud or have i just wired it up up wrong, or an i missing something like an amp. any help would be good thanks. here is some links to the component specs http://www.datasheetq.com/view.jsp?pn=WTV020M01&fac;=ETC⟨=en

Have been using my FolgerTech Prusa i3 printer for a few weeks now, and was doing some cable management when, "Pop!" goes the power supply. I had the mains power unplugged from the power supply, and didn't connect or disconnect any other wires. I was working on hiding some endstop cables (That i will probably just go ahead and shorten later) and when i was satisfied with the job, i went ahead and plugged the printer back in. Pop! Immediately unplugged the printer to prevent further harm. Sounded as if a .22 went off in my room. No burning or acidic smell, just a pop. From the sound of it, i assumed it had to be the power supply. So i examined everything, the ramps boards, the arduino, etc. Nothing. Everything looks fine. I remove the power supply from the printer, and plug it back in. LED light stays off, no more sounds. Using my multimeter, i checked the output voltage, and sure enough, it's dead. So i go ahead and crack the power supply open, and begin examining the components. Nothing. Absolutely nothing. All the caps look fine, no charred marks, no scorches or burns. No component looks any different than its functional counterpart. Beyond the cheap chinese soldering job, the board looks fine. So i take the board off of the metal plate to examine the backside. Solder splatter everywhere, but no shorts or anything (It worked for about 3 weeks.). I do, however, notice that there is a nice dry joint on one of the large capacitors. Thinking that might be the problem, i go ahead and fix the joint by reflowing the solder. Put it back in its case, plug it in, nothing. Anyone have any idea what may have happened? I am a student who currently doesn't have 30$ to fork out for another power supply, but do have an arsenal of spare electronic components. (Will eventually buy another power supply, but currently don't have money to set aside for it.) What should i look for? What blew up? Why does it not work anymore? If any more info is needed, let me know!

Hello I bought a pir sensor off ebay (SKU 14_B000101941) and I plugged it into a solderless breadboard to test it out. I connected a 3v LED between the output and ground and while it does light up, it does not light up when it senses light, it just turns off every 2 seconds, then every 5 seconds. If there is a simple fix to this problem any advice would be appreciated but if not I am willing to buy a different one.

 I have a Sony Ericsson W200i one year ago. I wanted to put music and themes in it, but I only had a iMac (shared). The phone came with a CD called "PC Suite" but it is only for windows. So I just plugged my phone in and dragged dropped files in to my phone. I did that a couple times and my phone was fine, then next time I wanted to plug it into the iMac, the phone will not reconise the plug or the computer. So I took it to the phone shop for repairs, and the guy said there was nothing wrong. Now I got a HP windows computer, so I installed the CD, plugged the phone in - same problem Comments will be appreciated. 

I fixed a break a week ago, now both dog collars are not registering. the fence alarm is not sounding, so I replaced both batteries in the dogs collars, still nothing, got any ideas?

I've been kicking myself for months now trying to get my flybacks to operate. It seems that no matter what driver I build, or how carefully I assemble it, the only thing I get is silence. Even the simple 2n3055 driver does not work for me. I've checked the transistors, they appear to be fine. I have no idea what to do. Any ideas?

HV starting pulse is normal, but then output voltage drops to around 1.5-2VAC.  no obvious damage to PCB or components within.

I just purchased an Iphone 4S from verizon 2 days ago, it is the white model. However, the Internal Speaker will not work, and has never worked for anything: Apps, Music, Videos, Ringtones, etc. I made sure the phone was not on silent mode and the volume was up high.  I thought that the headphone detection could be malfunctioning, however when in music, I set the volume to highest possible with no headphones and then plugged in my headphones and the volume bar went to the previous setting with headphones. This makes me assume that it knows to play out of the speakers. Help would be appreciated, if the solution is not fixed, I will be trading in the phone at verizon.

I am running a RAMPS board Prusa i3 on the newest version of Repetier Host, and everything worked fine on the last computer I had. I set Repetier up on a new computer, and everything functions as it should except that when I try to start a print, it says a print is in progress, but it's not printing. The stop/pause buttons are there as if a print is in progress, the bottom right corner forever says its printing layer 0, and the manual control window does not show a print in progress. Testing has indicated that the motors and heaters respond correctly when using manual controls, so the problem isn't the connection, baud rate, etc. Nothing was changed in terms of the hardware or firmware of the printer itself. The print runs fine using the virtual printer simulation. I also tried deselecting the box for "check extruder and bed temperature". Does anyone know what would cause the print to fail to start?

Edited:  I'm having trouble getting all my stereo/TV components hooked up in the correct sequence so that each component functions as needed. All my components are Sony the cable box is Motorola (DCT700). TV (Sony KV-27FS13) with 4 input lines (Video 1, 3 & 4 from the back. Video 2 through the front panel.) Everything was rewired today to include a new cable box (due to the digital conversion) and I can see TV channels okay.  VCR (Sony SLV-798HF): On Video 1, I can view channels (when VCR is on CH3), and the cable box controls the channel, but I cannot record any other channel but the one controlled by the cable box. I can also view VHS tapes. DVD Recorder (Sony RDR-HX780): On Video 3, I can view channels controlled by the cable box, but I cannot record any other channel but the one controlled by the cable box. I can also view DVD's. I have a Sony Multi Channel AV Receiver (Model # STR-DG510). I don't know if that helps with getting this to work or not. I've included a detailed diagram. Any advice or help would be greatly appreciated. Thanks, canucksgirl Currently the coax goes to the cable box, to the DVD, then to the VCR and then to the TV. RCA-DVD: from the cable box goes to the DVD player (in). From the RCA out goes to TV RCA in. RCA-VCR: RCA out on VCR goes to RCA in on TV.

I searched Instructables to be certain I am not covering something someone else has already done, but found nothing.  Here is an excellent article on troubleshooting a bad string of Christmas mini-lights. (I do not know the author and am not connected to him in any way.)  I know of three occurrences of non-working light strings from this year's celebrations. In the first case, the woman who owns the Christmas tree simply bought a new string of lights and hung the new lights over the old string attached at the factory to her synthetic tree. I did not see her tree and cannot say what the cause of the malfunction was. In the second occurrence we put up a synthetic tree with two strings of factory installed lights, one for the bottom half of the tree and one for the top half of the tree. The string on the top half worked some of the time, but then would go out. Typically one suspects a bad bulb. That is also the general suggestion made in the very fine article I linked above. However, that proved not to be the problem. Rather, the problem was the very cheap electrical plug. I cut the plug from the string so I could open it and determine exactly where and how it failed in order to satisfy my own curiosity. Installing a new male plug solved the problem. In the third case, my daughter had a string near the top of her tree that was "out," but not completely at the top. I had limited tools and resources, but plugging the bad string into a different molded female plug brought it back to life. The moral of the story is that while a bad bulb is a frequent source of problems, the molded male and female plugs on these inexpensive light strings are often held together only by a lick and a promise, and fail easily. Giving the molded plugs a hard look is much easier and faster than removing and testing bulb after bulb. The first photo shows an extension cord with molded plugs from three strings plugged into the extension cord. The second photo shows the bad male plug on our tree, and I am using my multi-meter to test for continuity between the brass plug blade and the load end of one of the tiny fuses inside the plug. That part tests "good." The other fuse tested "good," too. In the third photo I inserted a straight pin into the wire and tested for a circuit from the brass blades to the wire. Both sides failed this test.  A multi-meter can easily test what I needed to find this problem. I would have needed to strip away some insulation from the wire or stick a straight pin through the wire to obtain a reading with my multi-meter. But, by this time I had bought a hum tester with a high and a low range for checking different voltage ranges on an AC circuit. It led me to know the plug was the problem. 

Ok..long story short.. built this Instructable: (minimal Arduino on poerfboard,.  w/ blank Atmel) I put this on a breaboard instead https://www.instructables.com/id/Perfboard-Hackduino-Arduino-compatible-circuit/ I then installed Arduino IDE, as well as WinAVR/avrdude I tried to build a parallel programmer: http://www.arduino.cc/en/Main/ParallelProgrammer but it didnt work.. (not sure if it because of WinAVR?avrdue setting?  but command line AND flashing bootloader through Arduino IDE did NOT WORK.. AVRDUDE gives this response: avrdude: can't open device "giveio" avrdude: failed to open parallel port "lpt1" pinout for parallel programm was as follows: PP     ATMEL  (pinout) 1    -  19 2    -  17 11  -  18 16  -  1 18  -  GND on breadboard*** no clue even Ive asked and googled.. couldnt find a 'real' solution to this.. so I looked around..and I found a couple MAX232 chips laying around..figured Id use these to build a Serial Converter using this tut: http://sodoityourself.com/max232-serial-level-converter/ I this all set-up on my breadboard: (pics to check what Im doing wrong) *******(the images shows the vRegulator moved over 1 pin..it has been corrected but after pic was taken) http://dmstudios.net/misc/max232_circuit/top.jpg http://dmstudios.net/misc/max232_circuit/1.jpg http://dmstudios.net/misc/max232_circuit/2.jpg I have checked the vRegulator portion..  I have a cap BEFORE the regulator  *bridging GND & output* and I use my meter to check that there is, in fact, 5v coming from it..  and there is... HOWEVER...  the vRegulator gets SUPER HOT, SUPER FAST!... if I dis-connect the pin 16 form the  chip to the ++ then the vRegulator does NOT get hot... once I bridge it.. instant HEAT.. so is it something I have done wrong in my diagram? http://dmstudios.net/misc/max232_circuit/diagram_1.jpg vRegulator not show in diagram here;; in this diagram.. as soon as I hook up the V++ to pin16 on the chip.. and the cap..etc  something is wrong?? I 'do' have some FTDI cables coming from China for a few bucks.. but this is ONLY for sketch uploading...correct? I also have a true Arduino Due coming as well... but hate waiting weeks when I want to play and get started now! Any help is appreciated..   Im new to all this, so be nice!  LOL thanks gang!

I am making a POV (persistance of vision) project using atmega8 ,which is being programmed by arduino (uno) as ISP i am following this tutorial videos and blink led code is working well   for me as in the video, I tired the same code by changing the delay for verifying whether the circuit works properly  and i was working nice But i uploaded my persistance of vision code(POV) its no working   none of the leds is blinking I using the correct pin i verified it with arduino uno atmega8 pin mapping Here is my Persistance of vision code int _[] = {0,0,0,0,0, 0,0,0,0,0, 0,0,0,0,0}; int A[] = {0,1,1,1,1, 1,0,1,0,0, 0,1,1,1,1}; int B[] = {1,1,1,1,1, 1,0,1,0,1, 0,1,0,1,0}; int C[] = {0,1,1,1,0, 1,0,0,0,1, 1,0,0,0,1}; int D[] = {1,1,1,1,1, 1,0,0,0,1, 0,1,1,1,0}; int E[] = {1,1,1,1,1, 1,0,1,0,1, 1,0,1,0,1}; int F[] = {1,1,1,1,1, 1,0,1,0,0, 1,0,1,0,0}; int G[] = {0,1,1,1,0, 1,0,1,0,1, 0,0,1,1,0}; int H[] = {1,1,1,1,1, 0,0,1,0,0, 1,1,1,1,1}; int I[] = {0,0,0,0,1, 1,0,1,1,1, 0,0,0,0,1}; int J[] = {1,0,0,0,0, 1,0,0,0,1, 1,1,1,1,1}; int K[] = {1,1,1,1,1, 0,0,1,0,0, 0,1,0,1,1}; int L[] = {1,1,1,1,1, 0,0,0,0,1, 0,0,0,0,1}; int M[] = {1,1,1,1,1, 0,1,1,0,0, 0,1,1,1,1}; int N[] = {1,1,1,1,1, 1,0,0,0,0, 0,1,1,1,1}; int O[] = {0,1,1,1,0, 1,0,0,0,1, 0,1,1,1,0}; int P[] = {1,1,1,1,1, 1,0,1,0,0, 0,1,0,0,0}; int Q[] = {0,1,1,1,1, 1,0,0,1,1, 0,1,1,1,1}; int R[] = {1,1,1,1,1, 1,0,1,0,0, 0,1,0,1,1}; int S[] = {0,1,0,0,1, 1,0,1,0,1, 1,0,0,1,0}; int T[] = {1,0,0,0,0, 1,1,1,1,1, 1,0,0,0,0}; int U[] = {1,1,1,1,1, 0,0,0,0,1, 1,1,1,1,1}; int V[] = {1,1,1,1,0, 0,0,0,0,1, 1,1,1,1,0}; int W[] = {1,1,1,1,0, 0,0,1,1,0, 1,1,1,1,0}; int X[] = {1,1,0,1,1, 0,0,1,0,0, 1,1,0,1,1}; int Y[] = {1,1,0,0,0, 0,0,1,0,0, 1,1,1,1,1}; int Z[] = {1,0,0,1,1, 1,0,1,0,1, 1,1,0,0,1}; int letterSpace; int dotTime; void setup() {   // setting the ports of the leds to OUTPUT   pinMode(2, OUTPUT);   pinMode(3, OUTPUT);   pinMode(4, OUTPUT);   pinMode(5, OUTPUT);   pinMode(6, OUTPUT);   // defining the space between the letters (ms)   letterSpace = 6;   // defining the time dots appear (ms)   dotTime = 3; } void printLetter(int letter[]) {   int y;   // printing the first y row of the letter   for (y=0; y<5; y++)   {     digitalWrite(y+2, letter[y]);   }   delay(dotTime);   // printing the second y row of the letter   for (y=0; y<5; y++)   {     digitalWrite(y+2, letter[y+5]);   }   delay(dotTime);   // printing the third y row of the letter   for (y=0; y<5; y++)   {     digitalWrite(y+2, letter[y+10]);   }   delay(dotTime);   // printing the sspace between the letters   for (y=0; y<5; y++)   {     digitalWrite(y+2, 0);   }   delay(letterSpace); } void loop() {   // you can print your own text by modifing here :) printLetter(H); printLetter(E); printLetter(L); printLetter(L); printLetter(O); printLetter(_);   } Is there any solution ???

I am making a POV (persistance of vision) project using atmega8 ,which is being programmed by arduino (uno) as ISP i am following this  tutorial videos and blink led code is working well    for me as in the video, I tired the same code by changing the delay for verifying whether the circuit works properly   and i was working nice But i uploaded my persistance of vision code(POV) its no working  none of the leds is blinking I using the correct pin i verified it with arduino uno atmega8 pin mapping Here is my Persistance of vision code int _[] = {0,0,0,0,0, 0,0,0,0,0, 0,0,0,0,0}; int A[] = {0,1,1,1,1, 1,0,1,0,0, 0,1,1,1,1}; int B[] = {1,1,1,1,1, 1,0,1,0,1, 0,1,0,1,0}; int C[] = {0,1,1,1,0, 1,0,0,0,1, 1,0,0,0,1}; int D[] = {1,1,1,1,1, 1,0,0,0,1, 0,1,1,1,0}; int E[] = {1,1,1,1,1, 1,0,1,0,1, 1,0,1,0,1}; int F[] = {1,1,1,1,1, 1,0,1,0,0, 1,0,1,0,0}; int G[] = {0,1,1,1,0, 1,0,1,0,1, 0,0,1,1,0}; int H[] = {1,1,1,1,1, 0,0,1,0,0, 1,1,1,1,1}; int I[] = {0,0,0,0,1, 1,0,1,1,1, 0,0,0,0,1}; int J[] = {1,0,0,0,0, 1,0,0,0,1, 1,1,1,1,1}; int K[] = {1,1,1,1,1, 0,0,1,0,0, 0,1,0,1,1}; int L[] = {1,1,1,1,1, 0,0,0,0,1, 0,0,0,0,1}; int M[] = {1,1,1,1,1, 0,1,1,0,0, 0,1,1,1,1}; int N[] = {1,1,1,1,1, 1,0,0,0,0, 0,1,1,1,1}; int O[] = {0,1,1,1,0, 1,0,0,0,1, 0,1,1,1,0}; int P[] = {1,1,1,1,1, 1,0,1,0,0, 0,1,0,0,0}; int Q[] = {0,1,1,1,1, 1,0,0,1,1, 0,1,1,1,1}; int R[] = {1,1,1,1,1, 1,0,1,0,0, 0,1,0,1,1}; int S[] = {0,1,0,0,1, 1,0,1,0,1, 1,0,0,1,0}; int T[] = {1,0,0,0,0, 1,1,1,1,1, 1,0,0,0,0}; int U[] = {1,1,1,1,1, 0,0,0,0,1, 1,1,1,1,1}; int V[] = {1,1,1,1,0, 0,0,0,0,1, 1,1,1,1,0}; int W[] = {1,1,1,1,0, 0,0,1,1,0, 1,1,1,1,0}; int X[] = {1,1,0,1,1, 0,0,1,0,0, 1,1,0,1,1}; int Y[] = {1,1,0,0,0, 0,0,1,0,0, 1,1,1,1,1}; int Z[] = {1,0,0,1,1, 1,0,1,0,1, 1,1,0,0,1}; int letterSpace; int dotTime; void setup() {   // setting the ports of the leds to OUTPUT   pinMode(9, OUTPUT);   pinMode(10, OUTPUT);   pinMode(11, OUTPUT);   pinMode(12, OUTPUT);   pinMode(13, OUTPUT);   // defining the space between the letters (ms)   letterSpace = 6;   // defining the time dots appear (ms)   dotTime = 3; } void printLetter(int letter[]) {   int y;   // printing the first y row of the letter   for (y=0; y<5; y++)   {     digitalWrite(y+2, letter[y]);   }   delay(dotTime);   // printing the second y row of the letter   for (y=0; y<5; y++)   {     digitalWrite(y+2, letter[y+5]);   }   delay(dotTime);   // printing the third y row of the letter   for (y=0; y<5; y++)   {     digitalWrite(y+2, letter[y+10]);   }   delay(dotTime);   // printing the sspace between the letters   for (y=0; y<5; y++)   {     digitalWrite(y+2, 0);   }   delay(letterSpace); } void loop() {   // you can print your own text by modifing here :) printLetter(H); printLetter(E); printLetter(L); printLetter(L); printLetter(O); printLetter(_);   }

Hi, I'm fairly new to electronics and I'm trying to learn it with my Arduino. Recently I have been working on a project that involves 4 potentiometer(pot). I'm using one 1k pot and 3 10k pot. The pot is used to send signals to the analog inputs of the arduino. To test the pots I used a simple serial.println program that sends the value of the pot from 0 - 1023. When I connect the pot through its 3 pins directly to the breadboard, all of them work perfectly fine and gives me a stable value as I turn the pot. However, when I soldered three wires to them each, 2 of them work and 2 of them didnt. The 1k and one of the 10k pot didnt work. When I connected it through its wires, the values it gave kept jumping even when I'm not turning the knob and sometimes it will just stay one value when I'm turning it or not. Why is this happening? Did I overheat the pot when soldering? I took some new pots and tested them again through the pins directly and it worked perfectly fine. But when I soldered the wires to it, this time the 10k worked fine and the 1k didnt work. It gave the same problem as the ones before. Please help me with this problem. I have attached the pictures of the pots that didn't work. Please help me check if my soldering is anything wrong. I have checked online couldn't fine anyone experiencing the same problem. TQ! 

OSIM uSqueez permanently dead. Dismantled unit found mother board 2A fuse blown. Check everything OK on mother board and replace fuse. Power on unit led under stop button light up. Pressed vibrator button works perfect. Pressed massage button strong sparking sound and saw fire in one to two second followed by blown fuse. 1. Measure the motor terminal resistance -> 0 ~ 5 ohms. Or it should should have some high resistance approximately 10 ~ 50 ohms. 2. Measure BR-B3D thermal protector which was in series with the black wire -> 0 ~ 5 ohms. Any idea which one is faulty part? 1. Think the thermal fuse is OK. 2. If the motor short, shall I do rewinding for rotor? Can't found this motor locally and if buy direct from OSIM too expensive! Any idea measure rotor coil? Thanks

My fridge/freezer stops working every few days

I am having some trouble getting an Instructable (Cat Genie hack) based on an Arduino board to work. This is the first microprocessor project I've ever tried and I am hoping someone here might be able to help me troubleshoot. I figured by posting the question here I might be able to get more help, faster, and from people who have experience with Arduino code. If I can't get it to work with a simple code fix I'm hoping I might be able to put something in the code that will allow me to troubleshoot where exactly the problem is occurring.Instructable link: https://www.instructables.com/id/CatGenie_Resetting_a_SaniSolution_Cartridge/?comments=all?

After working on a tesla coil off and on for a few years I finally finished building one, but it is running into several problems. The only problem that I can't figure out is that despite following the basic tesla coil diagram the toroid will not create a jumping spark; however the gap generator still produces a spark. The coil is running off of a 15kv nst with a gfi built in.

I built myself one of Moosapotamus' Bass Paraloopers following his design (the updated one, that is) to the letter.  The only modification I did was to remove the low pass filter, since I'm using it for guitar, not bass.  Unfortunately, it has several problems. The one I am most concerned about is some unwanted distortion.  It is fairly mild, but noticeable enough to be a problem when playing clean.  It affects both the dry and wet signal (i.e. it is present when the blend knob is set to both 100% wet and 100% dry).  I do not think the signal from the effects pedal in the loop is overdriving the circuit.  How can I narrow down where/what component this distortion is coming from?  Unfortunately, I do not have an oscilloscope to use for troubleshooting.  Any help is appreciated.

I got a Eurorack UB1222FX-PRO sound mixer/whatever from my school a while ago. It was broken and wouldn't turn on so that's why I got it. I'm not exactly sure whats wrong with it but im pretty darn sure that something is up with the power supply as nothing on the board is even powering on. But there is some power coming out of it to the main board but im not sure if its just not enough power or what. I know my chances of anyone on here knowing whats up are pretty slim but I don't have anything else left to do, and it doesn't hurt to ask. Im not exactly sure what to be testing or how to test things for that matter. It doesn't look like anything is wrong with it. I have a digital multimeter but it doesn't have many settings and im not sure if im testing parts on the right setting. sometimes i get readings and sometimes i dont. Anyway, if someone could maybe guide me through a troubleshooting process that could possible narrow the problem down that would be great. if not ill just scrap it and steal all the parts out of it.  If you need more pictures or more information i'd be more than happy to provide them.  EDIT: I doubt this will help any but here is the manual: http://www.behringer.com/assets/UB1222FX-PRO_M_EN.pdf

I recently built an amp using lm386 ic. It works really well but it makes a buzzing sound while playing and while ideal with no input and power on.

Hi all, I just recently got my hands on an LG Rumour 2 (Bell Network). I was happy until I realized that I couldn't upload my customized ringtones. Is there a way for me to hack into my cell phone or work around this? I'd really like to be able to add my ringtones without paying for them.

​Looking for help on my project.  See image.  Testing before connecting to high voltage device.  Using a 3v relay triiggered by the PIR signal.  As you see wired now, There is no ground wire coming from PIR.  The circuit would not trigger relay with a ground wire to the PIR.  When this does trigger I noticed on the relay that the LED would not go completely off.  So I check to find that when relay turns "off"  the PIR is still sending 2.8 volts to the relay.  Not enough to trigger the relay, but enough to show power through the LED.  Obviously something wrong here where the PIR or Relay are still drawing power.  Can you help?

I am an amateur with setting up circuits, but I am really interested and understand most electronics, I am just confused with the issue I am having. Background:  I am building a wireless google cardboard so that I can play PC games on my phone through the VR headset rather than crappy app games. Basically a wireless Oculus Rift, however I know it wont be anywhere near as good it's just a fun project. I have Infrared LEDs which I will use with freetrack and my modified webcam without IR filter to do my head tracking. Issue: I am trying to power 3x Infrared LEDs from a usb powerpack. Here is the one I am using http://www.ebay.com.au/itm/221468778309?var=520334132263&ssPageName;=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 The reason for using this as a power source is I can easily attach it to the headstraps on the google cardboard, it is just about the smallest power setup I can think of (better than using 3x AA batteries), it was cheap, and it outputs 5v which is perfect for powering 3x IR LEDs with a forward voltage of 1.6v and 60mA current. When I use this powerbank to power a single LED without a resistor and I look at it through my webcam, even with all the lights off and the webcam 5mm away from the LED you can barely see it light up. I tried the led on another powerbank I have here which is 10,000mAh so it is massive, and it was much brighter on the webcam. I then used my samsung TV remote and pressed a button while aiming at the webcam and it was EXTREMELY bright. Basically I want the LED to be as bright as my remote, or as much as the LED is capable of. Why would the powerbank show the LED so dull? I have confirmed it is outputting 5v, but when I try test the current with a 'usb charger doctor' between the charger and usb cable, or a multimeter between the wire and the LED it shows zero current. I should be able to just connect all LED in series with a small resistor and it should just work at full brightness, but the power bank cannot even power a single LED well enough to see properly on the webcam. It's becoming really frustrating, any idea what's happening? Best solution?

Hi,      I'm working on project with RGB LED strips with my arduino and a ATtiny84. Basically, what I plan to do is attach the strip to my display cabinet and attach the strip to an ATtiny84 microcontroller which will program the lights. Doing this I have encounter a few problems. As I haven't receive my ATtiny84 chip from the store yet, I'm testing everything on my arduino first. I first attached a normal single RGB LED to test all my programs and it works almost fine.       My first problem was when I attached 3 potentiometer(pot) to the arduino to control the intensity of each pin(red, green, blue). It did as it suppose to. When I turn the knob the brightness increase but as I'm reaching its maximum it drops back low again. So basically as I turn the knob gradually increasing, the brightness increase gradually from zero to it brightest then drops. I have attached a screenshot of this program below. I think it may be the connection between the pot and the arduino as they are quite sensitive but I'm not sure.       My second problem is when I replaced the single RGB LED with the RGB strip, MOSFETs(TIP120) and an external 12V supply it worked like before. I attached a couple of pictures of the layout below. However, when I set all the pins to low brightness the red and blue is turned off but the green led did not. The green led is dim but not completely turned off like the others. Why is this so? I'm very sure its not a defect in the strip. I hv also a attached a picture below of it.       My third problem is when I bought the three MOSFETs from the store I got one slightly different one although with the same label of TIP120. I have also attach a picture of the MOSFETS below.  The pin that is connected to this different MOSFET seems to act the opposite of its values. As in when I set that pin to low brightness it will be bright and vice versa unlike the other two. I can easily buy another one but I would like to know why this happens.       This is not really a problem but more of a question. As you can see I attached a 1k ohm resistor between the MOSFET and the arduino output to limit the draw of current. I would like to know what would you recommend the value of the resistor because I do not want to damage my chip. Is 1k enough?       My second question is I'm using a 12V 2A power adaptor as my power supply and a L7805 voltage regulator to provide a 5V power for my ATtiny84. However when I connect it I do not get a stable output and its value is around 5.3V. According to some videos I should attach a 0.1 microFarat electrolit capacitor to the input and a 22 microFarat electrolit capacitor to the output in parallel, however when I do so my output is still not stable and is around 5.8V which is too high for the chip as the max Vin for the chip is 5.5V. So what should I do?       My third and last question is my power adapter heats up when its powered but not connected to the circuit. Why is that? And my MOSFETS and voltage regulator gets hot occasionally. Should I attached a heat sink? Is this circuit possible to be left on 24/7? and how much power will it consume?       Sorry for the long post, I'm fairly new to electronics and I'm just a student  who is trying to learn electronics on my own. I have been working very hard on this project and I hope I get the best out of it. Sorry for the bad english too. Any help and comment will be much appreciated. Thank you very much!!

The front passanger side seat belt will not extract, come out.  Once in awhile it will work in my 2001 Toyota Sienna

Just finished with my arduino word clock; however, the words alternate every second instead of every five minutes. What could be the problem here? Just trying to get some ideas for troubleshooting this thing.  I used the sleek word clock ible if that helps.

I have a pair of vintage AR-4 speakers but one of the woofers is not working. Any ideas on how I might diagnose and repair the problem?

My childrens wii-mote stopped showing any sign of life at all.  I was hoping I'd find a guide showing a disassembly and possible troubleshooting steps.

I have recently bought a 5m strip of RGB SMD5050 300LED strip together with a 12v controller and remote control. I have cut and soldered this LED strip into numerous small parts, as suitable for my application (as additional car lights). However on powering up this LED strip, its colour is blue which keeps flashing at a fast rate (almost a strobe-like effect). This keeps going on, not responding to the commands on the remote control. Since this is my first time working with LEDs, I am unable to troubleshoot this problem. Would anyone be able to guide me please?

My two stroke honda 250 cc 1997 dirtbike is having trouble idling without me giving it constant throttle.  What are some of the things I could do to perhaps fix this problem?

B212D active speaker amplifier troubleshooting - driver stops after running for 20 minutes.Every time I switch on the speaker, it works for 20 to 30 minutes and after that the driver stops but the compression driver still works. Right after that, if I power off and power on then the driver works for one minute or so.Once it is cooled, if I start it again, it repeates same as above.Is it a capacitor issue or any other weak component? How to diagnose and fix it?It is a product from 2009 Behringer.Please help.