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Reed relay to reed switch Answered

Can someone help me. I have a reed relay and want to use it as a reed switch. Can someone tell me hyow to hook it up so it acts as a reed switch?

Question by Adum24    |  last reply


Fun uses for Reed Switches?

Reed switches are electro-mechanical devices that opens or closes a circuit when a megnetic field is present. They come in normally open and normally closed designs and range from the size of a grain of rice all the way up to several inches long. A relay, another electro-mechanical device, is comprised of a reed switch and an electromagnet trigger built into one housing. Common uses for reed switches (not counting relays which are used in virtually all electronic devices) include the 'pick ups' on bicycle computers and the sensors on window and door alarms. I just ordered a bunch of reed switches and I need your help in coming up with ideas for what to do with them. Post up your ideas for some things that could be made or modified to be triggered by a magnet coming in close proximity to a reed switch. Remember- the magnet does not have to touch the switch, just get close enough that the magnetic force trips the switch. The stranger and sillier your ideas are the better. Note: this is not a contest and there are no prizes. by posting an idea you are giving your consent for anyone who reads it to use your idea. Posts about integrating reed switches into knex firearms will be ignored (no offence, it's just not my cup of tea).

Topic by Handsome-Ryan    |  last reply


Reed switch wind speedmeter? Answered

Hello, I need some help with counting the pulses  on digital pin with reed switch and arduino for speed meter and also calculation for the speed in km/h.

Question by Konstantin Dimitrov    |  last reply


Coto 9202(150hom) 5v reed switch

Please can any one help.I am looking for a COTO 9020 5V reed switch with an internal resistance of 150ohms.I haven't had any luck in locating one. I was wondering if there was a alternative available to replace the COTO 9020 5V reed switch with an internal resistance of 150ohms.many thanksMike

Question by MikeC510    |  last reply


LED control via a reed switch and SCR

N00b question: I've got an RGB LED that has a forward voltage of 3.7v and a 3.7v battery pack. I want to trigger the LED to light via a magnet and reed switch. If I wire the reed switch to the gate of the SCR and have the SCR power the LED, will I be able to turn the LED on and off via the magnet by bringing the magnet near the reed switch?

Topic by d0ugparker    |  last reply


how to make a reed switch for sensing a magnet from 4 to 5inch distance? or a substitute with RF Answered

Experts, pls guide, that i want to know the way to make a reed (in DC) have to sense a magnet from a distance of 4 to 5inches. did small reed will act so ?? if a yes, then which specification have to look?? or did there any circuit or something for making it much more powerful??

Question by shinojmahe    |  last reply


Connect multiple Reed Switches to one Raspberry pi

Hi, I was wondering if its possible to connect multiple reed switches to 1 Raspberry Pi so i can get notified whenever 1 or more switches gets triggerd. thank you.

Topic by archi0112    |  last reply


How to create reed switch that activates wireless alarm?

I've been reading alot about reed switches after learning about a security feature for cars, a reed kill switch. I wanted to know how to or if someone could create some kind of setup where if the reed switch closes the circuit, it will activate a wireless remote or something like an alarm within a reasonable distance from the actual switch. I've seen those window/door entry alarms. Would those work? For a car, would it be possible to have the reed switch activate a small alarm in a key fob type of thing?

Question by booooyet    |  last reply


Create door opening wireless notifier? Reed switches? Answered

Hi, I have a Vellerman K8055 USB experimental board that I have hooked up to one of my machines. Yesterday, I took our wireless doorbell apart and with a multimeter found the signal that sparks the 'ding-dong' sound when the remote bell is pressed. I wired that into the K8055 and then to cut a long story short, when the bell is pressed, it pops up on my TV and tells me that someone has pressed the bell (using MythTVOSD multicast if anyone is interested). A link to the card: http://www.velleman.eu/products/view/?country=be⟨=en&id;=351346 What I'd like to do is to extend this mechanism to my doors. When a door is opened in the house, then I need a signal to be sent to a receiver device also wired into the K8055 so that I can capture that event in my program. I have thought about using magnetic reed switches on each door with hacked wireless doorbells (around 3-5 GBP on ebay from China). One problem I have is that I can only find 'normally open' reed switches, meaning that when the door is closed so will the reed switch contacts - this in turn means that I will be constantly notified (should I be able to make this work) that the door is closed. If I could find 'normally closed' reed switches, I could have one of each on each door, What is the cheapest/most elegant solution to this problem? Is using hacked wireless doorbells the way to go, or is there a better way. I'm a relative novice with electronics - I'm a dot net developer by day with experience of data capture cards, and have toyed with the Arduino, Lm386s, 555s, 4017s etc... some with instructions from this site, so whilst not a complete beginner, I am what I would call, "an enthusiastic amateur'.

Question by dchurch24    |  last reply


Need some ideas

Ok...at my other "home" www.geekstogo.com someone came up with a question about methods of making a "sherlock Holmes type chess board" where you could place one (or multiple) chess pieces in a specific location and have it open up a secret compartmentlinkage....and it got me really interested in attempting to build such a nifty contraption...we through out a bunch of ideas on how to get the chess board made and wired up....had some good ideas for using reed switches and either a push solenoid or even a linear actuator (to open and close a drawer depending on switch positioning)...i think i could work the wiring and stuff up...but what i need is some ideas for what to do instead of a chess board (i'm wanting to make this for my brother and his wife and i already got him a shot glass chess set...so he doesn't need another one of those)i though maybe i could make a water fountain where it would have a removable piece (or pieces) that when you put it in one location it will turn the fountain on and off...and if you put it somewhere else it would open up a drawer or something...i've got these faces from CPR dummies (don't ask) that i was going to use to make the fountain (like the water dripping from the open mouth) and either make some of my metal hands or buy some of those wooden art model hands or something...and make it that way...but i'm not sure if that's what i want to do (also not sure if the reed switches i'm planning on using are capable of switching 110v AC for long periods of time so suggestions on materials would be nice)another idea would be a big wall art piece like the Magnetic Multi Panel Mural...but i'm not sure how to integrate a drawer setup in something like that without getting inside of his wall at his house (would be fun though....wire it up in the wall...and have like a drawer open across the house when you move a panel or something like that)also...i guess it doesn't have to open up anything...it could do anything when the switch is on or off or whatever....any ideas are welcome

Topic by crapflinger    |  last reply


Inrush current limiting resistor size?

I am building an application where LED strip lights will be powered off a 12V DC battery and switched on and off using a magnetic reed switch. I've been finding that the reed switch often fails to turn off when the magnet is removed. Searching on the net suggests this is because the contacts are getting fused by a large inrush current and the suggested fix is to wire a resistor in series to prevent this - so far so good but I cannot find anywhere guidance on the rating of the resistor I should use - at least guidance I can understand - as far as I can tell a resistor as low as 1 ohm may be required but not sure if I have got this correct - anyone know? Thanks

Question by SeaF1    |  last reply


Does any one know how to rig a reed switch to a bluetooth device to notify you if someone has opened a door or not?

Im looking to see if anyone knows a way to rig a bluetooth usb drive or something to a reed switch to automatically connect to your cellphone when the reed switch is activated?

Question by JoshRidlon    |  last reply


Does an inductor start with a magnetic field, or does it only retain one as long as it is powered?

I am trying to figure out how to keep a reed switch on by proximity to a magnet. I read that an inductor stores the current as a magnetic force, so I was planning on just having the reed switch close to the inductor, and just use a small magnet to close the circuit initially. i was hoping the field from the powered inductor would keep the switch closed. Am I on the right track?

Question by redbaron1234    |  last reply



illuminated ball - remote switching and charging

I'm working on making an illuminated ball for playing bike polo with at night time. A couple of high output red LEDs are sufficient for light to get through a normal street-hockey ball. The problems I'm currently facing are switching the lights on or off, and charging the batteries. Ideally both of these could be done remotely - i.e. without having to open the ball up. For switching I was thinking of using a magnetic reed switch - when a magnet is attached, the lights switch off. The only problem is that reed switches seem to be (a) made of glass (not ideal when the ball gets hit really hard), and (b) in a normally-open configuration - I'd need a normally closed one for this. As for charging, I have two ideas - one is to have two small metal pads on the surface of the ball to connect to the charger. This could be problematic due to forces on the ball during gameplay. The other more fun idea would be inductive charging. Like what you get in those fancy electric toothbrushes. One coil inside the ball, one outside. How practical is this? can it supply the necessary voltage and current to charge either a pair of NiMH batteries or a Li-ion cell? vik

Topic by askvictor    |  last reply


switch to control dc when ac is turned on?

Hi i've got a arduino project on the go and when my arduino switches on a relay to operate a 240v ac motor, i also want it to turn on 24vdc motor. I know i could just use another relay but i'm not wanting to power the relays separately, just want to power the aurduino, and yes the board might be able to power two relays but it's pushing the limits i think.  I'm not to sure if this is called a reed switch or even if there is something like what i am after available?  

Topic by JonathanM221    |  last reply


3 Float/Reed Switches Controlling a 16 Pixel RGB LED Ring via UNO

Good evening, My latest project is for a level indicator on my chicken coops water supply.  I am using an Arduino UNO, 3 reed float switches and a 16 pixel RGB LED Ring (adafruit Neopixel).  I have the switches at 3 different positions in the water tank. I am wanting to light the RGB LED ring a different colour depending on which switch is closed.  The bottom one red, the middle orange and when at the top, green. I have the LED ring working.  I also can have the switch working on its own.  But not controlling the LED. I have no idea what to do next.  I am thinking that i need to get the switch turning the LEDs on.  Then I can start thinking about using all three at once. I am hoping someone can help?  It seems a simple task for the arduino to do but I am very new at this so I'm struggling a little bit. Thank you all in advance.

Topic by NuclearGreyhound    |  last reply


i want to use a real foot pedal on my rock band to make it work i can use any reed switch normally open or no?

I want to create a rock band pedal so ineed exactly the same reed switch as they show on the instructions or i can use another models

Question by coqu1    |  last reply


With an electromagnet, if there's a open reed switch betwen 1 end of the coil's wire & powersource, will e-mag get hot?

I'm building an electromagnet. The core is soft iron: 0.5" diameter and 1" long.  AWG 12 wire OR enameled copper magnet wire 32 gauge So the wire is wrapped around the core. One wire end leads to a reed switch which connects to one of the two wires of the 9 volt snap-on battery clip. The other wire end connects straight to the 9 volt snap-on battery clip with nothing in between. Will the wire end that connects directly to the 9 volt snap-on battery clip: A.) use powers and drain the battery B.) heat up the electromagnet (wire & core) If the electromagnet heats up, then how hot does it get? Just warm or really warm? Could it reach hot or HOT levels - hot enough to burn skin, damage any part of the electromagnet, or ignite/melt the carpet (if it was on it)?   P.S.  The final device would have no exposed wires. Thanks.

Question by gatorgirl7563    |  last reply


Seat belt fastened circuit

I have designed a circuit the intent of which is to control the seat belt fastened light on the dash.  There are two switches.  1. A pressure switch that closes when someone is in the seat.  2. A Reed switch that closes when the seat belt latch is latched.   Each works correctly separately.  I am using a standard 12V automotive relay to control the light, as below.  Let's just look at one side. 1. When the ignition on the 12V wire connects to the two leads, i.e., the pressure switch and the reed switch. 2. When someone sits in the seat the pressure switch closes and the dash light, which is connected to the relay at 30 and 87A comes on (relay not activated).  3. When the seat belt is latched, the reed switch closes, the relay switches and the current between 30 and 87A turns off. Diodes are introduced in the circuit as shown in the diagram.  The problem is that is does not work correctly.  Sit in the seat and the light comes on.  Buckle the latch but the light does not go off. There is still 12V between 87A and 30, but I don't know why.  I also tried putting a diode between 85 and 86 (pointing towards 86) but that did not help.  Suggestions please.

Topic by DaleR18  


Easyest way for a arduno interrupt to call a funtion? Answered

Hi, I am trying to build a arduino speedometer for my go kart. I need a function that is called everytime a pin goes from low to high using a reed switch. The curcumfrence of the wheel is about 1m. The absoltue maximum this kart will be able to go is about 100km/h (28m/s). So the arduino pin will need to be able to be read 28 times every second. What is th best way to make the arduino call a function on a pin that needs to be read at least 28 times per second?

Question by David97    |  last reply


How can I float a small ring magnet? Answered

I am creating a fluid level indicator for my automated drink mixer and need either an alternate solution or an item that can float a small ring magnet. Currently, my idea is to sink a reed switch into a straw, with a ring magnet around the straw.  Once the magnet floats down to the reed switch, it lights up the indicator that the alcohol is (almost) gone. Unfortunately, I cannot find a durable non-toxic way to make the magnet float.  I've done several searches and the closest matches I've found are fishing tackle, which I'm not sure would work all that well.  I've found manufactured devices, but $30 per bottle is a bit much to spend.  I'd like to keep it to under $5 per bottle.

Question by kidmosey    |  last reply


i live in latin america and idont know the name of the reed switch in spanish so i can buy it

I wanna know the name in spanish of a model i can use in the rock band custom pedal

Question by coqu1    |  last reply



Need arduino sensor advice! - Inductive touch vs. reed vs. touch sensative

Hi everyone - I am trying to make an elevator for my daughter's doll house - it is all set on a stepper motor and arduino - but I need a way for it to know when it has reached the bottom floor. Also, for reasons too strange to go into here though, I need it stop exactly when the elevator hits the ground floor.I am hoping the simpler the solution the better...a reed switch with a magnet on the bottom of the elevator? or a Pressure sensitive resistor? Or a push button that is really sensitive?Any suggestions would be much appreciated.THANKS!

Question by jpalay    |  last reply


do I need to isolate a negative ion generator?

I am looking to build a negative ion generator based spark gap... I need to limit dielectric loss, and need to use 8" of small gauge wire to and from the switch to turn it on. do I need to isolate the switch electronically from the rest of the circuit? if so, would a reed relay do the trick? if I use a reed relay, could I run it from the same power source, in parallel, or do I need to isolate power sources as well? my setup will be slightly similar to the Electrifried shoe diagram below. (no, that's not the project)

Topic by gschoppe    |  last reply


Can someone help with my anti auto theft arduino device? I am trying to use a reed switch and a relay.

     I am trying to build a device for my engineering project which is a anti theft device for cargo trucks in third world countries. Since cargo stealing is very common truckers already use satellite tracking. The device works in the following way, in an attempt to steal the truck a thieve tries to breach into the truck"s electrics to disable the satellite tracking, but the reed switch detects the breach and the arduino stops feeding power to a relay which is connected truck's electronic fuel injection system, thus making the truck's engine to stop and consequently immobilizing the cargo.      The system uses a 4x4 matrix keypad, one relay(I might add more) and one reed switch but I am planning to use two. When the sensor is breached the arduino is supposed to cut power to the relay. If the correct password in entered in the keypad the system turns the relays on until the sensor is breached again, if the wrong password is entered it remains locked.      I managed to find a password code a guy shared which worked with the keypad and the relays, but when I try to add a if statement to lock when the sensor is breached it simply does not work. Thanks in advance for the help. #include int Relay1 = 13; int Relay2 = 12; int greenPin = 11; int Sensor1 = A1; int Sensor1Valor = analogRead(Sensor1); int position = 0; const char * password = "123"; const byte ROWS = 4; const byte COLS = 4; char keys[ROWS][COLS] = {   {'1','2','3','A'}, {'4','5','6','B'}, {'7','8','9','C'}, {'*','0','#','D'} }; byte rowPins[ROWS] = { 8, 7, 6, 9 }; byte colPins[COLS] = { 5, 4, 3, 2 }; Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS ); void setup() { Serial.begin(9600); pinMode(Sensor1, INPUT); pinMode(Relay1, OUTPUT); pinMode(Relay2, OUTPUT); pinMode(greenPin, OUTPUT); digitalWrite(Relay1, HIGH); digitalWrite(Relay2, HIGH); setLocked(false); } void loop()  { char key = keypad.getKey(); Serial.println(analogRead(A1)); if (key == '*' || key == '#') { position = 0; setLocked(true); } if (key == password[position]) { position ++; } if (position == 3) { setLocked(false); } if (analogRead(A1) > 300); { setLocked(true); } } void setLocked(int locked) { if (locked) { digitalWrite(greenPin, LOW); digitalWrite(Relay1, LOW); digitalWrite(Relay2, LOW); } else { digitalWrite(greenPin, HIGH); digitalWrite(Relay1, HIGH); digitalWrite(Relay2, HIGH); } }

Question by LuccaL1    |  last reply


name for Altoids robot? Answered

I need a name for altoid bot im creating it has to attenas on the front a reed switch and skid steers runs on a picaxe microcontroller motor driver board . iknow this isnt a real question but in some sense it is it need to be cool no altoid robot or somthing lame like that

Question by mman1506    |  last reply


What is sending out the signals ? Answered

Hi, I opened up the remote controls of my old alarm system ( those reed switch ones) hoping to find some IR LEDs. But I got this instead, no IR LEDs. Can anyone tell me which component is sending out the signals ? Thanks in advance.

Question by fujiapple    |  last reply


anyone know if this curcuit will work?

Basically I am building a robot and I have reworked some servos on a rc control to switch current from + to - and back to - and + depending on which way the joystick is. so at the top of the pic is my + - in that can switch to - + I need a curcuit that will run to different relays depending on the direction of current. Will the one I made work. I'm wondering if the power will feedback throught the other relay. by the way the black arrows are diodes Also does anyone know the difference between a reed relay and a regular relay. I looked it up but it doesent make much sense.

Topic by kendallickes    |  last reply


I need to make a 7-12 second delay timer, how?!?

For my delay timer, i will need to be able to turn the POWER on/off and activate the timer with a button press. i only dont wanna have to turn the power on/off to reset it. So, i'd have a power switch, and a timer activate/reactivate button. It will activate a reed relay. THANKS!!!!!!!!!!!

Question by sci4me    |  last reply


Can anyone write me code for arduino wheather station with 433mhz TX and RX? Answered

I need code for arduino wheater station, which uses sensors: LM35, BMP180, Reed switch ( wind speedmeter) and a potentiometer for wind direction. I use 433mhz TX and RX I will need and code for the RX but to use serial to read the data.  P.S. with Manchester. h Thank you !!! 

Question by Konstantin Dimitrov    |  last reply


Need Help With Project

I am working on a high rocketry project. I want to made a launch detector. My idea is to use a magnet reed switch (PN# ORD2212) and a electromagnet. Which I will turn off about 2 seconds before launch, to give a 2 seconds base line. I will use magnet powder (around the switch) so when the electromagnet is on it will hold in place, then drop off when the power is remove, opening the switch signing the fight computer to start flight operations. The unit is 20mm Wide/15mm Length/35mm Height (screen shot attached). My question is what magnet power should I use? It has to be as light as possible. Also how do I calculate the electromagnet (appx 12V)?Thanks for the helpRichard

Question by Rocket Nut    |  last reply


Using an electric shock to trigger an arduino. (doorknob variety)

I was thinking a transistor, how does one make ~20000v at 5mA useful. Do I use a capacitor or a coil of some type? Do I NEED an amp? Will it be jittery? I was even looking at those alfoil leaf static detectors and imagining some sort of field detecting reed switch.. ? Think frankenstiens lab: lightning=reaction :)

Question by oliverkellow    |  last reply


I need to scavenge some solid state relays. 5v 120vac. What types of things have these in them?

I am trying to power some Christmas lights with my computer speakers and need some solid state relays to switch them. I tried the reed type from radio shack but they keep sticking. I have lots of random electronics laying around to scavenge from, any suggestions would be greatly appreciated

Question by Deathstick    |  last reply


What do I have2do2a wire2let me power a9v thing from a outlet? Can a9v battery clip only carry 9v? Screw terminal uses?

I'm trying to invent something. I'm realistic enough to know it probably won't work as planned and definitely won't make me rich, but I'll always regret it if I don't try. I need to power 6 electromagnets and I want to use one cord to power them. The electromagnets are wire wrapped around a soft iron core. They don’t need to be strong, just strong enough to activate a reed switch. (The pictures are labelled with #s to show which question they are for.) 1. How do I connect them all into an electrical extension cord? Do I have to use a screw terminal? 2. Can a 9 volt battery clip carry more than 9 volts, or will it fry? If I properly joined a power cord and 9 volt battery clip and plugged it in, what would happen? Would there have to be resistors? What kind? 3. Would this configuration with two screw terminals work? Did I misunderstand the function of the screw terminal? Is there something better I could use? (From bottom to top) ~The electrical cord powers the whole thing. It distributes the current to all the wires. ~The reed switches prevent the all wires from sending all the currents to the light bulb. ~If I put a magnet over the AQUA wire reed switch, the circuit would be completed and current would reach the light bulb and cause it to light. I tried to figure out how to do it on my own but when you don't know any electric components, terms, phrases, and definitions - like me - it's next to impossible to look things up.  

Question by gatorgirl7563    |  last reply


Why flashing Laser Died?

I have a laser pointer from the dollar store which I have hacked to fit a usb cord. 3 button batteries came with the laser, so, I figure 4.5v is right. Then I was hacking a magnetic door alarm (siren when the magnet is away from it) Again- 3 batteries, so 4.5 v plus or minus x. The alarm hack is to provide pulsing DC when the magnet is spun in a drill past the reed switch in the alarm. So, I plugged the laser into the pulsing DC, and it worked for a while, then crapped out.Why did it die? slightly different v from different chemistry in the batteries?or from flashing?

Question by Toga_Dan    |  last reply


How can I build an door alarm that sends a signal wirelessly to buzzer maybe 30m away when the door is opened? Answered

I need to hear the front door open from quite a way away and I can't really run wires all the way. The signal would need to travel wirelessly from the front door of my business to the buzzer at the other end of the premises.I can't seem to buy a pre-made version nor a kit for this anywhere! Would there be a way I could use a kit with a reed switch ie magnetic sensor on the door but somehow wire it to a transmitter instead of a buzzer? Then I'd need a receiver connected to a buzzer I suppose.  I've no idea really where to start.

Question by Lydboots    |  last reply


old phone? Answered

Today i was given a old phone. but its certainly a different phone, it has a cord, but the end on the cord is the same as one from a internet cord, but when i plug it in to a computer it has no effect. i think it might be a 'bag phone', all i know is its made by motorola. instead of trying to figure it out, i figured i would strip it down for parts, but other than the speakers, microphone, leds and a magnetic reed switch there isnt much. one thing that really interests me is the lcd screen it has, there arent very many pins connecting it to the board, it has a microship embedded of the back of the lcd board, covered in that wierd glue. does anyone know how i can reuse the lcd? would i need an arduino for it?

Question by zack247    |  last reply


Modifying doorbell to register a SmartThings device connection?

I'm hoping someone can help me here. I've got a Byron BY601 Wireless doorbell which comes in 2 parts - the chime and the doorbell. The Chime takes 3x AA batteries, and the doorbell takes 1X CR2032 battery. What I'm trying to do, if figure out a way that when the doorbell is pressed, it activates the connection on a SmartThings device. I have a SmartThings multiswitch which can acts as a Reed Switch for an Open/Closed signal to SmartThings, this however, takes a  CR2450 battery. I've attached some images, but I'm wondering if anyone reckons they might be able to figure out just by looking where I could make some connections to trigger the device to activate?

Topic by K20Evo    |  last reply


How can I apply a calculation to a frequency counter?

I am trying to find a way to convert frequency (as in cycles per second (literal cycles of a wheel)) into speed. I've found schematics and code for a frequency counter, but I want to be able to display the actual speed in MPH in LEDs. The calculation is simple enough to do - I just need to know if there is a way that I could covert the output of a frequency counter to MPH by way of some calculation, and if so, how.  essentially, I want to learn how to program, say, a PIC micro to read how often a reed switch is closed, then translate that into a readable speed on 7-segment leds. where should I start? what kind of chip should I use? Where do I learn to code? I am pretty much lost thanks for reading

Question by phephq    |  last reply


Could I have some help coming up with a circuit that turns it self off after three momentary button presses?

Hi, I was wondering if I could have some help coming up with a circuit,  Basically me and my friend are modding nerf guns and I thought it would be cool If I could find a way to make the rapid strike fire three darts then stop (or three round bursts XD) Any how the part of the dart gun this in-tales seems to be the little arm that pushes darts into two rotating discs (this is one that uses fly wheels as opposed to a plunger) it works on a motor and gear that pushes it in and out, pushing the trigger activates this.  (I thought it would be a solenoid and that the trigger would put out electricity in bursts, or are those called pulses? any way that's where all this using a momentary switch idea comes from) So if anyone thinks that they can make a circuit using only the power from the trigger and lots of good timing a lesson would be much appreciated :D My Idea seems unnecessarily complicated but it's all I could come up with :D ,Any way the idea for the momentary switch circuit would be put some form of proximity sensor switch near the arm (the one that pushes the dart into the fly wheels). Something like a magnet switch or IR thingy ( I forgot what there called I think magnetic reed switch and Infa red proximity sensor or detector?) the idea after that was that each time the arm passed the sensor it would activate the sensor,  using that and the trigger(if they were both needed to initiate the circuit then releasing the trigger would reset the circuit) the first and second shots would push the dart into the fly wheels and the third would also push a dart into the fly wheel and turn off the circuit(or turn on the circuit activating a spdt relay and switching the link to the motor off) So far I've come up with some ideas using relays but just pressing the button once activated the whole circuit, I've also though of using a capacitor but I don't really know how to use them, if they work by holding X charge that can be filled by pressing a momentary button, that is hooked up to Y amount of power (possibly through a resistor), Z amount of times fills the capacitor stopping the circuit that would work,  though I would have to find a way to discharge it... Thanks for any help if I get any XD , and if posting my current not working circuit designs would help I'll do that, just have to figure out how to draw a circuit...

Question by justomeguy    |  last reply


Why wont this led flasher circuit work?

I recently made an led flasher circuit using a 555 timer on a breadboard. The instructable I used was this: https://www.instructables.com/id/How_to_use_555_timers/When I made the whole thing on the breadboard, it worked. (I used a reed relay instead of a switch for the power, so i could use a magnet to turn it on and off and it worked). Then I took the circuit and transferred it to a circuit board. I made the first part, with the one led that just lights up, and when I tested it, it didnt work. I checked and made sure power went through all of the objects, and it did. The breadboard circuit I used a 5+ power supply, on the circuit board I used a battery holder (That holds 4 1.5 batteries) to get 6 volts. (I used 6 volts with the breadboard circuit, too) I used all the same pieces, tested the led and it worked, but it just doesnt work. Here is the circuit drawn on paint (As it is on the circuit board):

Question by 101yummYYummy101    |  last reply


Would this automatic curtains / blinds controller design work?

Hi all, I have been searching for ways to make an easy and cheap automatic curtains/blinds controller but have not really seen any that actually meets my basic needs but also does not require lots of complex IC components. Please let me know of any instructables I may have missed. So here is my design - hoping everyone can help to validate it and discuss design faults and improvements (mainly to reduce costs). The Requirements: 1) Costs: Total costs should be around $20 per curtain. I think professional systems cost about $100-$200 per curtain controller. 2) Parts: Easy to build and put together with some soldering. Parts are easy to find/buy or substitute for similar components. 3) Function: At least 2 buttons. One UP button and one DOWN button for manual triggering (wireless buttons would be better). 4) Function: One press of Button A fully opens the blinds with the motor stopping at the correct place to avoid damage to the blinds or the motor. The opposite goes for Button B to close the blinds. 5) Function: The controller should never be able to open or close the blinds past the normal safe positions, causing damage. 6) Optional Parts: Complete system is small enough to fit inside the blinds/curtain's cover / awning. I think it should be easy to fit in most covers anyway. Briefly how it should all work: With the curtains rolled up, you would press button A, which would roll the curtains DOWN, then stopping at the correct place (covering the whole window). Pressing button A once again would not do anything or further roll DOWN the curtains. Then, press button B and the curtains should start rolling UP constantly, stopping just before it gets to the top. Pressing button B once again would not do anything or further roll UP the curtains, avoiding damage to curtains or motor. Design/diagram below (sorry for the poor details, i used MS-Visio to draw it out). The Parts/Components (under $30 at time or writing): 1) 5-10kg servo $7 (using 5volts) that can be power in forward or reverse spin. Slow spinning speeds would be best for safe and low power operation? 2) Some hand made adapter to firmly connect the servo motor shaft to the curtain's shaft to spin/roll the curtains ($0 free). 3) A wireless power relay $14, (12 volts) with 2 channels and "constant on power" functions (links below). I guess wired relays are fine, but I would want to hide the wires to the buttons. 4) 2x 5V regulators $2, to reduce the 12v power from the Relay to 5v for the Servo. 5) 2x Magnetic or reed switches $5 (12 volts) that is Normally On (normally connected). 6) 4x Rare earth magnets $1 to work with the reed switches. These are small, thin and easy to hide, but are very strong. 7) A power source for the relay, 4x 18650 batteries?. Should be 12 volts or depending on what relay & servo combo you use. (links below) Construction: 1) Make an adapter to connect the servo to the blind's shaft. I dont have a picture of one or the steps for this as every servo & curtain combo situation will be different, but im sure it should be simple to make. Fail or malfunction of this part would cause too much damage to anything really? 2) For best practice, use temporary wiring to connect all the components together as per diagram and test out the functions as if they were installed in their places and on the blinds. 3) Glue or connect the adapter, curtain shaft and servo shaft together. Also mount the servo firmly somewhere, on the wall or curtain cover so it doesnt end up spinning itself. 4) Position both magnetic switches on the wall, behind and just under the curtain's roll of fabric as per diagram. A lot of testing and playing around will be needed to create the correct gap between each switch and curtain.    Switch A   (Limiter A) will be the most difficult to position. It will be used to stop the servo from rolling the blinds too far down. This means the magnet glued on the blinds is up high on top, which will be rolled inside layers of fabric and may spin close to Limiter A multiple times which may cut the circuit/power earlier than intended as the magnet spins round and round. Limiter B should be easier. 5) Wire the 2 channels on the relay to the Servo and the Limiters. The 5V regulators goes between both channels of the Relay's power OUT and the Servo's two power Inputs. Screw or glue the relay to somewhere firm like inside the curtain covers. 6) Glue the rare earth magnets to the desired positions, or sew them on if you dont trust the glue. The magnets will physically cut the power to the servo by activating the Magnetic reed switches, so using 2 magnets would be even better, just incase the servo you use spins really fast or has a lag. 7) Connect the relay to the battery/power cable. Of course double check all is good before adding power. In my case, I will have 12v power cables available to use. 8) Put the curtain cover back on to hide everything. Hopefully you did not create creases in the curtain fabric where the magnets are glued. Oh and maybe remove the curtain draw strings (used to pull up & down the curtains) to avoid breaking the Servo? Detailed explanation of how it should work: - The blinds are fully rolled up. - Press Button A once, Relay provides power to Channel A, Servo spins clockwise constantly (rolling down the curtain). - Servo's positive line A is cut (circuit open) when Magnet A rolls out and comes close to Limiter A. Relay is still outputting power to Channel A but no power goes to the Servo. - Press Button A once again, the Servo should not do anything. The Relay should then stop outputting power to Channel A. - Further presses of Button A does nothing but toggles Channel A's power on and off. Magnet A & Limiter A still disabling power to the Servo. - Press Button B once, Relay provides power to Channel B, Servo spins anti-clockwise constantly (rolling UP the curtain). - Servo's positive line B is cut when Magnet B rolls up close to Limiter B. Relay is still outputting power to Channel B. - Press Button B once again, the Servo should not do anything. - With this "latch" functionality of the Relay (see link below and product details), it is also possible to stop the curtains mid way, which might be useful for some people, i dont think i will use it. For future upgrades: I think it would be possible to control this controller from a PC program, by directly connecting IO cables to the Relay's button A & B on the PCB. Sending pulses from the PC as though it were remote button presses. Or just bring the remote to the PC's IO ports and connect there. Would anyone disagree? Links: - An example Servo: http://www.ebay.com.au/sch/i.html?_nkw=High+torque+Metal+Gear+RC+Servo - The wireless Relay: http://www.ebay.com.au/sch/i.html?rt=nc&LH;_PrefLoc=2&_nkw=2CH%2012V%20Wireless%20Relay - The 5v Regulators (L7805): http://www.ebay.com.au/sch/i.html?rt=nc&LH;_PrefLoc=2&_nkw=5v%20regulators&_fln=1&_trksid=p3286.c0.m283 - The magnetic reed switches: http://www.ebay.com.au/sch/i.html?_nkw=reed+switch - The rare earth magnets: http://www.ebay.com.au/sch/i.html?_nkw=rare+earth+magnets+n38 - Design/diagram: http://i50.tinypic.com/118emas.jpg

Question by sonhy    |  last reply


Auto restart circuit or software for external FireWire hard drives?

Hello community,  I own a few external hard drives, plugged in FireWire in the Mac, and for whatever reason, when left idle for a good length of time, they cannot spin back up, and it appears as if they crashed. Usually, I quickly power-cycle them, which seems enough to restart them but not unmount them. For the manufacturers, the drive don't have any defect as spin-down is the expected behaviour.  So currently, I was considering a crude circuit based on a 555 (I have about ten of them) or a 556 (just 1) that would automate this power-cycling, and would connect as a multiway switch. I found some long-delay repeat timer designs, but still unsure what form the final stage would be, considering up to 2A (probably more during startup) probably flow through the switch. I though about a reed relay, but they are difficult to find and quite bulky to be integrated in the external drive. The other delicate part is that the end-stage must not stay in the off state for more than about half a second, otherwise the hard drive will be unmounted The second main drive subject to this problem is more complicated, as it doesn't require any external power source but takes it from the FW port. Alternatively, I thought about a very simple (algorithmically speaking, because I know absolutely nothing there) script that would 1- detect when the drive is present. 2- When it is, every hour, delete and rewrite a small file to a partition, causing the hard drive to stay on. At least one software do that, but has an exorbitant cost of $12 to circumvent a flaw in the OS. Any idea, one way or the other?

Topic by Cubytus    |  last reply


I need help with programming the opening and closing of a lid?

Okay so I'm trying to build something that will allow the li I placed on a vial to open and close according to the time protocol I assign it on Audrino. The lid is a flip, spring action lid made from hard plastic. The programming shouldn't be a problem, but I wanted to see if there is another easier way to go about this keeping the whole thing under 100grams. At first I was thinking adding Velcro to the top on the lid and on the side of the vial that the lid retracts to. The lid moved by a micro piston of some sort all powered by a watch battery a chip programmed by Audrino. But I was thinking if there is some sort of mini lever arms or somehow rig a magnetic reed switch with a magnet an use the polarities to push pull the lid? I'm just having trouble with the design, getting very frustrating. I attached a picture of a very very quick doodle of what I mean. The top design is with the Velcro idea. Thank you so much, really hope I learn something from you guys and others too!! Picture of ideas: http://i.imgur.com/pREJ9O3.jpg Thanks again!  :D  sorry for long message! 

Question by Aehtesha    |  last reply


Another idea for a piece-tracking chess board

RFID-based chess boards have their merits of course, but would be pretty expensive and could potentially suffer from antenna cross-talk. Furthermore, the relatively immense amount of information carried compared to what's required makes RFID sort of overkill. Reed switches have the opposite problem, only carrying a single bit of information per square (piece present y/n). It seems that what you want is something in-between (six kinds of pieces, two colors, so you only need four bits of entropy per square/piece).My idea is the following:Each square is a circuit containing a signal generator connected to four bandpass filters at frequencies f1,f2,f3,f4 (multiplexed of course, so that we only need a few signal generators/filters)Each piece has a RLC circuit in the foot (with fairly large inductance)The circuit in each piece is tuned to resonate at frequency f1, f2, f3 or f4, or any combination of the fourTo poll a square for information, we mux to the square's circuit and generate sin(f1) + sin(f2) + sin(f3) + sin(f4). Now we should be able to discern which piece is on the square based on the frequency response observed at the output of the bandpass filtersIf I'm not completely missing something, the resulting PCB should be comparatively cheap to construct. But I'd love to hear if this is a less elegant solution than I think. Are there any problems with this idea?

Topic by BenjaminL136    |  last reply


Looking for a cheap compressor with a high pressure rating or for airbrush use?

Today a friend of mine asked me if I know a way to reduce the noise level of his compressor in the work shed. With the current heat he prefers to work in the evening and nights, which does not make his neighbours too happy. His main use for several airbrush guns and sometimes for mormal airtools or the big spray gun for an undercoat or similar. So his main concern is oil in the airline and the actual flow rate is of second concern as he has an old 25kg propane cyclinder as an additional air tank. For relative low air volumes I would suggest an old fridge compressor. With a thicker pipe at the outlet that is filled with stainless steel wool most of the oil stays in the compressor. That is if this pipe is a) long enough b) upright c) of sufficient diameter so there is enough for the oil to avoid it being pushed up A second, standard oil seperator will be enough for the oil level required for airbrush stuff - and most other things too. If there is no pressure regulator on the airbrush system it is best to add a small air tank and shut off valve for it. In our case however a fridge compressor would be just enough to keep the bigger airbrush gun running but not to fill the tank at the same time. Not to mention the problem of fluctuating pressure levels. Since we already had a tank and pressure shut off connected to the loud compressor it was only a matter of finding something that keeps the neighbours happy. The first thing we did was to check how often the compressor comes on and how long it runs till the tank is back to pressure. With that and the stated air volume on the compressor we guesstimated that something a bit bigger than the compressor of a window airconditioner should be sufficient. The search begins.... If you don't know what to look for I give you a few hints: Older airconditioners often run on R22 or R12 - both use quite high system pressures which is a bonus, but more on that later. As a rule of thumb for these compressors you cans say: the bigger the higher the flow rate. At the local wreckers and scrap yards we found a few units but noticed the bigger ones often used three phases and not just one :( So we opted for the R22 compressor of a 4.5kW unit. Keep in mind the 4.5kW is for the entire system, so the quite massive fans can be removed from the sum. Usually the compressor alone is the 2.5 - 3kW range. Ok, we found the big thing but how does this help us? First things first ;) The oil was removed as the housing stating the original oil amount. This allowed us to use an oil rated for air use that has little to no water absorption qualities - you don't want water in your compressor. With the usual heat the water should be no problem anyway. Next was a pressure test to make sure the thing actually still works, so we added some plumping in the form of standard connectors to the inlet and outlet. We got well above 200PSI and abondoned the test at this stage as it was more than enough already. The air volume seemd to be well more than expected too so let'S move to the next stage. A fridge or aircon compressor always needs to have a certain amount of oil in it as it will otherwise seize and overheat quickly. But they are also designed so that the oil mixes with the refrigerant to cool all moving parts. So the biggest hurdle is to make sure the oil stays where it should stay and won't enter or get lost in the tank. Only real option for this to use something to catch the oil that is capable of releasing it into the compressor once it shuts off. Now there are several options for this so I start with the most basic: A "catch can" will get most of the oil, especially if filled with stainless steel wool or similar. Downside is that you have to find a way to get it back into the compressor. A step better is a thicker pipe filled with stainless steel wool to catch the oil. If placed upright and the outgoing pipe can be bend a bit upwards you have a good chance that most of the oil will sweep through the valves and get back down into the compressor housing. But only too often the cheap or even free compressor is better than expected and the oil won't get back into the housing as the vlaves are just too good. The last and IMHO best option is a pressurised return system. Most compressors for bigger aircons have a seperate filling port or sealed off piece of pipe. In this case you can do a simple check to see if they are usable for our purposes. Open the port of pipe and use a simple bike bump or similar to get some pressure in it. With a dedicated oil filling port you are best off but they are hard to find. The air you pump in should come out of the high pressure side - you might need a little pressure to overcome the valves. If you hear any bubbling in the housing (use a pipe on your ear or a sensitive microphone) it means you are going through the oil inside the compressor - perfect! You might not hear any bubbling but the port or pipe is still usable. Get ready with your fingers and start the compressor. The fill pipe should be sucking air in, same for the service port if there is one. A dedicated oil port should not suck but instead force some oil up if you cover the high pressure outlet. I assume all is good and no oil is splashing out of the open pipe or port. Add a small amount of oil with a syringe or similar into the port/pipe. If you see an oil mist coming out of the high side it is bad news. Clean outlet air is good. To get the oil back from the catch pipe or can we have to add a hose or pipe with a needle valve. It needs to be adjusted so that there is only a very little airflow (or oil mist) coming out. This regulated outlet is now being connect to the port/pipe with a bit of suction that we found earlier. Now every time the compressor runs the collected oil is forced back into the compressor :) Please double check the port/pipe used is not directly connected to the intake port! The last thing you want is a puddle of oil going into the cylinder and damaging it! They are designed to move gas but not liquid! If in doubt use a hardened sttel nail or similar to create a small puncture in the top of the compressor housing if there is nothing else to use. Check first if the material sound very thick, if so it might help to drill with a 5 or 6mm drill first - only about 1mm to make sure you won't enter the housing and conimate it with metal shavings! Once you have a small puncture hole of about 2mm in diameter get some 2 component metal repair glue mix and add a suitable connection for the collecting pipe/can. If you feel up to it you can of course use a blow torch and solder the connection on. Now we have the compressor working with a oil return system that also gives up very little to no oil at all in our system. You might now think you are good to go but you should at least add a decent and fine filter to the air inlet ;) The compressor noise of a bigger system can still be an issue if thicker pipes are used that allow the noise to travel out. Keep in mind they usually run in a fully closed system.... As we only need to match the noise level of the compressor itself a solid steel can like an old fire extinguisher in the 1kg rage is a good way out. Fill it with filter wool and a fine filter pad after adding some hose connectors either end. You can misuse the trigger nozzle and keep it to seal the top if you braze a connector on it. If the intake here is about 5 times larger than the pipe connection to the compressor itself the air flow going into the thing is low enough for a cheap paper air filter can or box if you have a quite dusty enviroment to work with. The real trick is to have a hose or pipe on the inside of the fire extinguisher connected to the compressor pipe connection. A garden hose is great here as is reduces the noise quite good and is dirt cheap. Make a lot of about 2mm sized holes in this pipe and close the other end of it off. Now the compressor will suck it through the small holes and the soft garden hose reduces the noise, the surrounding padding brings it down to basically nothing. The special case of clean air for airbrush.... If you read this for the sole purpose of airbrush use then this chapter is just for you, all other might want to skip it. The two things you don't want to enter your gun is oil or water. Both are a common thing in normal compressors due to lubrication and pressure difference resulting in condensation of the humidity in the intake air. Oil free compressors of good quality can cost quite a few bucks and often require ongoing replacement of membranes or piston seals. A refrigeration compressor with the above modifications already provides clean enough air for most airbrush users if a proper tank is used to store enough of the compressed air. So you might just want to add a basic oil filter or very fine paper filter close to the regulator. For very detailed work with very sensitive paints you might want to build a filter box containing of several layers of oil absorbent paper. This stuff is often used in the industry to clean up minor oil spills and bind oil very well. A PVC pipe (pressure rated please) with 5-8 layers of filter screens should last about a lifetime before the filters need changing if the diameter is in the 10-15cm range. That leaves us with the dreaded problem of condensation and water contamination. Depending on the type of paint and gun used a small amount of water vapour is usually no problem. Solvent based paints usally show their disliking by unwanted drops or run offs caused by water droplets. Of course you just go and buy a professional dehumidifier and accept the ongoing replacement costs for the cartridges... But if you are in a climated that has above 30% humidity for most of the year than you will have to remove the water one way or the other. A big enough storage tank for the air that is upright usually helps to release any condensated water prior to usage. But if you use a homemade tank you might want to avoid this problem completely and forget about water in the system altogehter. Silaca gel is the answer here, specifically the indicating variety that changes color once "full". A spaghetti glas or similar should be big enough unless you are in a very humid climate - is so just use multiple in a row. The air intake side for the compressor has to go through the silica gel to be effictive. This mean we need two holes in the lid. One with a pipe or hose going all the way to the botom - that is the air intake side. The other right on the lid - this is the air outlet side which continues to the compressor intake. With the color change in the silica gel we can estimate how much usage we have left until we have to heat it up to remove the water. If this color change happens quite fast from the bottom to the top, let's say within three days or less than you really need to use more jars with silica gel in a row or a longer one - like using a long and clear acrylic pipe instead. Of course you can always just cut holes and "viewing glasses" along the length to a PVC pipe.... No matter how wet your climate is you want to get at least 100 hours of compressor run time before you need to recharge the silica gel. This brings us to the recharging.... Once the color changes and you only have about one quarter left to the top you want to get the water out of the gel and re-use it. To do this you simply heat it up in your oven to around 120-150°C - the supplier should state the max temp for this. If you use a gas oven or one with limited accuracy here it is best to stay within the 120° range. You need to stir and mix the gel or use something big enough like an oven tray. But be aware that these little balls are like glass! The roll and bounce like no tomorrow! IMHO it best to use an old cooking pot that has no plastic handles for this and not to overfill it. This allows for easy mixing without making a mess that might cause a bad trpping hazard on your kitchen floor tiles! Once the gel is back to original colr it is time to let it cool of to a safe temperature and to fill it back into our canister or pipe. Tanks and shut off systems.... We have a refrigeration compressor working for us, and since it was for R22 we can use much higher pressures as a simple compressor from the hardware store. The low pressure side is used to 70PSI or around 5Bar of pressure in normal working conditions. The high side often works at pressure in the range of 200-300PSI or 14-20Bar! The tank we used is a big propane tank that was restamped at some stage in his life for the use of LPG - so it was tested to quite high pressures. The lower pressure limit is what keeps the stored gas liquid at the given temperature. For Propane at an imaginary 30°C this would around 155PSI or 10Bar. The stamped test pressure, although outdated, showed 600PSI or around 40Bar of pressure with no problems - and the thing was thick in the walls... The old shut off switch from an old air compressor was adjustable after removing the safety cap with a bit of force and the help of few cold beer. With a little tank attached we adjusted it to turn the compressor off at 250PSI or around 17Bar of pressure. If your tank is old or has no test pressure stamped on do your own test in a safe location. Make sure the area is secured so there is no chance of debris from a brusting tank can go anywhere - this includes to chain down the tank itself ;) Use the aircon compressor to fill it up to 300PSI or 20Bar of pressure - this should be tolerated with ease by any propane or LPG tank. Shut the valves and let it rest for a day or so. It is best to do this in the early morning so the heat from the day will slightly increase the pressure. At the end you still want to have a working tank and no major pressure losses. All of our mods on this tank were done without actually harming the tank. This was possible as the original valve had a release port for filling purposes - as it standard on most refillable ones. Here we removed the valve and added a pressure guage instead - better to know what is happening than to assume things. As this "port" had a seperate connection to the bottom of the brass valve we added as T-connection to allow for the connection to the compressor. Just be be really sure a thin piece of copper tubing was brazed to the exit hole of this port so all incoming air will be going down and away from the outlet connection with the big shut off valve on top - which we use to actually isolate and close the tank when not it use. Last thing required was something to connect the pressure shut off switch and regulator to. That was the only major expense on this project as we had no old BBQ hose or similar to get a suitable connector to the tank. We bought a simple adapter for the use of smaller hoses and cut the unwanted bits off we there was only the bottle conntector with the nut left. After removing the rubber ring we brazed piece of copper pipe onto it. Here we drilled holes and fitted severy connectors. First for the pressure switch, then for the connection to the pressure regulator and two standard ones with a ball valve for air hose connections. One air hose connection female, the other male so a standard compressor can be connected as well or "backfilled" for additional and mobile storage use. As we wanted to avoid any reduction in the safety and burst pressure no release valve was added at the bottom on the tank. The added silica gel filter stage was used instead so no water will get into the system to begin with. Additionally, and painfully for me and me friend, the inside of the tank was coated with a layer of acrylic paint to prevent and rust as it was free from it when we checked it at the beginning. This involved filling a suitable amount of paint into it, closing the top while keeping the thread clean and then to move the tank around to cover the inside evenly. If you do this be prepared for some weird movements with your friends LOL Once we were sure all ust be covered by paint at least three times we released the exxess paint and allowed the inside to dry with the assistance of some air forced to go in with a length of pipe. This was repeated 3 times... Then another two just for the bottom third of it where there might be some moisture after all... Now you don't want to remove the brass valve with everything connected to it just to turn the tank over to releae the collected water. Instead we made sure the added pipe on the former relese port would go all the way to the bottom of the tank. If any water collection is suspected only the connection to the compressor needs an additional valve for the disconnection so the water will be force back out here. To make this easy and fast we used standard quick connectors and a piece of flexible airhose rated to 20bar of pressure for the connection to the compressor. We checked the performance of the moisture removal and oil removal only for a few hours of running time while priming some surface for later use. The compressor oil used was very smelly to say it nice but nothing coul be smelled in the first paper filter after the pressure regulator. To check for remaining moisture levels (65% humidity in the house) we used a 10m length of clear PVC tubing going through an ice bath. After 30 minutes of moderate air release there was no condensation on the inside of the tubing visible. Of course if you only need it for air supply and don't care about a bit of moisture and oil you can keep it simple ;) Benefits of doing such a stupid thing: For starters noise and the peace of mind that you can do a lot of airbrushing until the compressor needs to kick in again. Then of course the benefit of an almost silent system compared to a standard compressor - something you can actually tolerate while doing art. But the real deal is knowing YOU did it and you did it for cheap. Warnings and some advise... I know, it should be at the very beginning but I just hope you read till the end ;) If the compressor fails from overheating you are up for a new one. This means the tan size should be within the limits of what the compressor can handle - same for what you actually use on air. You want an empty tank to be filled before the compressor feels hot to touch - quite warm is fine but if you can't leave your hand on it then it is too hot. Same story for the usage. There is no point in using a tiny 10 liter storage tank if you need that capacity every few minutes. The compressor would only have little pauses and overheat quickly. You want a good balance of usage time before the tank goes below supply pressure and running time of the compressor to get it to full pressure again. This brings us to the safety of high pressures. Where possible only copper tubing or sufficiently rate hoses should be used, the later as short as possible to avoid them acting like a whip if something goes wrong. When it comes to the safety of the tank you want to make sure to stay withing it's rated limits. All benefits of a compressor capable of producing over 500PSI otr close to 35Bar is wasted if your tank and pressure regulator can't handle it. This must not mean that you try to use a gas cylinder of unknow age and pressure rating and assume it will work! If in doubt use a lower shut off pressure and stay within the limits of normal air compressors - which is around 120PSI or 8Bar. Never, ever use a tank that is compromised by inside rust or bad corrosion on the outside! If you don't know how to braze copper tubing, pipes and connectors then check out some of the great Instructables about it! Whenever you know you won't use any compressed air for more than a few hours close all valves especially the ones going back to the compressor on the high pressure side! Some compressors really don't like a huge pressure difference constantly pushing on the reed valves. If your tank is big enough to allow for more than one hour of operation before the compressor has to top it up you might want to consider a one way valve right on the compressor outlet. This will prevent any massive pressures going onto the valves - especially helpful for modern compressors that only rely on the sealing capabilities of the clyinders or rotary system used. One thing you should always consider is a pressure relief valve rated for about 50PSI more than your tank pressure - it can be added to the pipe ;) If the shut off valve ever fails the relief valve gives you the ease of mind that it will blow before your tank does. Maintenance... If modded correctly the compressor should stay in the compressor and the compressor itself should not overheat from use. Having said that your compressor might force out a little more than your best catch system can handle. If that becomes a problem it might help to use an oil with a lower viscosity. If all fails it just means you need to top up oil once the last last paper filter is filthy or use slightly more to begin with so the intervals are longer. The silica gel, if used should be recharged before all of it is wasted - no point in adding it if you use it once full of water. If no gel is used there will be water in the storage tank. Even with the added paint and a good air filter it is possible that nasty things grow in there. Making sure the tank is emptied of any water after long uses and again before the next use is good practise. If no pressure gauge is used on the tank you must make sure the shut off valve is always working fine and within set parameters. I strongly recommend using a gauge and if not to perform a pressure check of the system every now and then to confirm all is within parameters of normal operation. A compressor constantly running means you either use far too much air or you have a leak - same story if the compressos kicks in after some of forgetting to shut it off and close the valves. If you keep the above in mind the salvaged compressor should work just fine for many years to come. Troubleshooting and alternatives.... You put everything together the right way, double checked and something is till not right? Maybe my crystal ball helps me to find something... 1. Always oil coming through the catch system. It usually means you use too much of it. A salvaged compressor, if the refrigent was removed legally from the system should still have a "correct" level of oil inside. Too much oil would mean is being pumped through the system at an excessive rate. Very thin compressor oils tend to do that in the compressor is misude like we do. Changing to standard mineral oil can help here. As a last resort you can use a pressure gauge or good judgement to allow more flow through the needle valve from the catch system back to the compressor. Too much backflow here would mean we loose system pressure to the set level of this needle valve! 2. The R22 rated compressor seems to be unable to produce enough pressure. First do a leak test using soapy water to rule out any leaks. Do a back pressure test on the ports. If you can push air through them in the reverse way with ease it means the valves are damaged making the compressor useless. You need to replace it. A regular cause with our type of usage is a constand back pressure from the storage tank to the compressor. To prevent this it might help to mount an electric solenoid between the compressor and storage tank. Such valve should be off when the pressure switch is engaged and on when the pressure switch is disengaged. This prevents the coil from overheating but requires a "normally off" type of valve. A good source at the wreckers are cars with LPG systems installed, they usually have suitable 12V valves somewhere on or near the tank and filler cap. 3. I am using several kg of silica gel but still get a lot of water in my storage tank. Going overboard in a humid climate can be a good thing here but if moisture makes it into the tank even with great amounts of silica gel there are only two causes: a) the tube or cylinder used is not long enough or not wide enough to allow the absorption of all the moisture going through. b) the flow rate is too high and the temperatures are too. For the first the solution is obvious enough. The second is related to the first for the diameter and lenght but temperatures constantly above the 30°C while operating somehow limits what the gel can do. Using a cooling coil on the intake side or simply putting the gel containers in icy water will help to a great deal here. If that is not an option than I suggest to layer the gel and to seperate it with fine paper filter screens. This will slow and even out the airflow allowing for more contact time with the gel. 4. The compressor gets very noisy after some time. If "some time" means more than 30-45 minutes you simply have it running too much and it overheats. If the noise increases too much when reaching the shut off pressure it can mean the pressure is too high for it. 5. Can I use multiple compressors from smaller units or refrigerators to get enough air volume? Of course you can but it might mean you have to lower your pressure expectations. Consider that each individual compressor would get the back pressure from all other compressors running while it's outlet valve is closed. To avoid premature failure you want to make sure the compressors are shut off at a lowver pressure. 6. I don't want to use a big tank but require a good airflow for airbrush. Two or three fridge compressors working one after the other with a small tank to keep the output pressure even can allow for about 30 minutes runtime per compressor. With three it gives one hour for the the first to cool off and should be enough for ongoing work. Downside is you need to make some sort of automatic switch to "rotate" to compressor working. Last words.... Is you find any spelling mistakes you can keep them. However, if you use them in any way to make a profit with them I kindly ask for 10% of your earning from it ;) Why did I not make an Instructable out of all this? Well the day was very hot, the beer very cold and my mobile phone at home, so I did not take any pics. To top it up the whole thing is now in a seperate box for additional noise reduction so it can be used in the same room where the guy is working. Of course he just used a nailgun for the job without any regard of access or at least easy view of the two pressure gauges. Typical if you have a great idea and the cold beer tells you to forget all about screws or hinges ROFL Only comment was: You created it and it works fine, why would need more than the pipe connections for the gel and regulator? Maybe he will reconsider when the service is due....

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