i really am trying to understand this decoupling thing. i've read and reread grumpy mike's tutorial. i don't have any inductors laying around to try out but do you think it'd be enough to decouple a couple motors with a .1uf and a 47uf capacitor?

am i doing this correctly? it feels wrong:

http://jeremycouillard.com/decouple_breadboard.jpg

is that motor decoupled? i'm just putting a couple caps in its path on the way to power?

thanks so much for the replies. i ordered a 5A psu so hopefully that will help also.

the 7805 has two capacitors on it and that's the only power to the IC. also the atmega has the capacitors on the crystal pins. is that sufficient? the 12v that goes to the motors and LED power wouldn't need to be decoupled, correct? or should i put a big capacitor on the motors? i've looked at grumpy mikes de-coupling page but it's really hard for me to understand everything totally i think....what is a choke or inductor? just a resistor? what size resistor would you know to use? would i do something like he shows at the bottom of his tutorial? http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

do you think decoupling or more amperage is the main problem? i will try both anyway once i wrap my head around how to decouple this circuit....

thanks so much for all the replies!

man...i so with i knew how to do both those things but unfortunately i don't know how to get amperage readings off my multimeter and i'm still trying to learn the schematic part in fritzing. might take another couple days. i was thinking this was an amperage issue also. i can hopefully find another wall wart with more amperage. but 1.7 already seems like more than enough to run 6 LEDs, some transistors, 2 relays and an IC, no?

also now i am noticing it's mostly the timing that is off. this program i wrote is a very time specific thing (timed to be in sync to a video) and currently the circuit has been running for awhile but the timing is changing a lot. could this mean something is off with the crystal?

[The problem is as follows]

hello,

i just learned fritzing so here is a poor attempt to show you the circuit i am working with. i hope you get the idea:

http://www.jeremycouillard.com/circuit.jpg (it's actually an atmega 328p but the pin config is the same)

the relays are not the ones i have but they are an spst relay that is turning the motors on and off and a dpdt relay that is reversing the polarity. the spst is 5v, powered by the arduino with a nominal current of 20mA. there is a diode across the coils. the dpdt is 12v and controlled through a tip120 transistor (with a diode). everything is powered through a 12v 1.7amp wall wort.

the leds are 12v, huge things and also are being powered separately and controlled through tip120s. the leds have a forward voltage of 3.5.

the code, pasted below, is very very simple. just starts the motors in one polarity, stops them, blinks some lights, then starts them again in a different polarity.
The problem is as follows: The program starts up and everything runs fine for about 2-3 cycles and then it either 1) just stops or 2) the relays and lights start turning on and off in a continuous loop...about 2 seconds on, two off. it is very strange....i've never had a circuit do something that wasn't in the code. Is there anything in my circuit that is suspect? any help/guidance would be so so appreciated!!!

Code:

void setup() {
  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(5, OUTPUT);
  digitalWrite(13, LOW);
  digitalWrite(13,LOW);
  delay(5500);
}

void loop() {

 
  digitalWrite(13, HIGH);
  digitalWrite(12, HIGH);
  delay(35000);
  digitalWrite(13, LOW);
  digitalWrite(12, LOW);

  //light show needs to be 11 seconds exactly
  //22 loops
////////////////////////////////////////////////
  for (int i = 0; i<22;i++){
    digitalWrite (11, HIGH);
    delay(100);
    digitalWrite(10, HIGH);
    delay(100);
    digitalWrite(5, HIGH);
    delay(100);
    digitalWrite(11, LOW);
    delay(100);
    digitalWrite(10, LOW);
    delay(100);
    digitalWrite(5, LOW);
  }
///////////////////////////////////////////////

  //delay(11000);

  digitalWrite(13, LOW);
  digitalWrite(12, HIGH);
  delay(36000);
  digitalWrite(13,LOW);
  digitalWrite(12,LOW);
  delay(2000);



}

thanks so much for the responses...but do you have any idea why this could be happening? or any other trouble shooting approaches? i've tried different relays, different diodes...it's just any time the diode is connected to the relay on both ends it stops working...if i just have the anode connected to he coil, it works...if just the cathode is connected...it works...but as soon as both are connected...it stops working...but in the same breadboarded circuit..no problems.

oh shoot...i was looking at it wrong. the diode stops working on the side of the relay that goes to the arduino. is there an order of the pins? like relay pin connects to diode, diode to arduino? or some other order?

so all my grounds are connected....do you have any idea why the coil is shorting out the diode in one circuit and not the other?

ok further testing and i noticed its as soon as i ground the relay that the diode give the funny reading. perhaps i am doing something different with my grounding in this circuit. how separate are you supposed to keep the ground from a 12v psu and the regulated current from a 7805? can the arduino and other components take the ground from the 12v psu? or do you make a separate ground from the 7805 center pin? ground is so confusing!

Hello,

I am using a 5v reed relay with a coil resistance of 250ohms, and contact ration of .5 amps and nominal current 20mA.

I have the same relay on a breadboard and in a perf board and it seems to be soldered together the same way. When it is in the breadboard, the relay and diode on its coil works. On my multimeter I get a normal reading...(when I put the multimeter on ohms, one side gives a reading, the other does not) however this same circuit in my perf board, when I test the diode, i get a reading on both ends...meaning when I flip the + and - on the multimeter i get a reading of like 200ohms either way...when I take the diode out of the perf...the reading is normal again...the diode works.

Any idea what could be causing this?

Hello,

I know the likelihood of this problem being solved isn't too high...but I thought I'd try.

A few months ago I made this kinetic sculpture (video of it in action and code is on the page): http://www.jeremycouillard.com/blog/05122012/

It's basically two motors, 2 sensors, 4 relays and some LEDs. When a sensor is tripped the relays reverse the polarity of a motor or stop it and some LEDs flash.
The sensors are in analog and when they go higher than 20 the atmega tells the relays to turn on the motors. This worked great. I had it running in a gallery for a month straight, 8 hours a day, 5 days a week. I crated it up, moved it, and now I want to rebuild it. I put it all back together just like before and it's like the chip does not even notice the sensors....the only time the sensors ever seem to trip is when I first plug the machine in and it runs only one of the conditionals I have that the sensors trip...whether or not the sensor is actually being tripped. But that's it. The sensors are working (they have little LEDs that are normally on and when they're tripped the LED goes off), the relay coils work, I tested them, I multimetered everything I could and it seems like current is flowing....I reflashed the program onto the atmega...same thing. The one motor keeps going counterclockwise and it's like the sensors aren't even there...when they're unplugged it basically does the same thing just without that first if conditional being activated.

I don't want to totally rebuild this circuit board but just in case, do you guys have any other troubleshooting ideas I could use to solve this?

Thanks so much for any help!

problem solved by uploading SimpleDigitalFirmata to arduino rather than StandardFirmata

Hello,

I am having a strange problem and banging my head into the wall.

I have some code on arduino (a Mega) that works fine but when I transfer that code to processing/Firmata using the arduino library it doesn't seem to work. I just want to push a button and have things happen on the computer.

So with the arduino code I have:
if (digitalRead(53)==HIGH) {
    Serial.println("53!");
    digitalWrite(13, HIGH);
    delay(50);
  }

And with processing I have:

import processing.serial.*;
import cc.arduino.*;

Arduino arduino;

void setup() {
  size(470, 280);
  arduino = new Arduino(this, Arduino.list()[1], 57600);
  arduino.pinMode(53, Arduino.INPUT);
}

void draw() {
  background(0);
  fill(255);

  if (arduino.digitalRead(53) == Arduino.HIGH) {
    ellipse(280, 280, 280, 280);
  }
}

But yet I cannot get that ellipse to draw. Oddly, if I change the HIGH to a LOW in the code and run the program, the ellipse is there. So it seems to notice the button maybe....there must be some small thing I'm missing here! I tried changing the caps on Arduino and arduino but that didn't work, I have simplified the code so it's exactly the same as the Arduino code! When I run the arduino library test programs in Processing everything works fine so I know I have everything hooked up correctly....

 What am I doing wrong???

**edit: the OUTPUT test program works in the arduino library for processing but the INPUT program does not. Does the library not work with an arduino Mega?

***edit2: downloaded the mega library from here: http://www.arduino.cc/playground/interfacing/processing
but in the library folder...nothing was there!!! So I got this one: http://nilseuropa.com/?p=139 but it still isn't working!

i replaced the two relays. still getting the same problem. all the relays work. all the diodes work...i can hear the little reed relays making their clicks and everything. but when i hook up four to the arduino and then attach the external power (in this case 6v 300mA, and also a different adjustable one trying all different voltages and 500mA), the powersupply gets no reading on the multimeter...i don't even have the motor hooked up yet.... when i detach the power supply from the circuit, i get a reading again. What is going on?! This is all I have attached.

The relays are wired as such:

pin 1 - 6v, 300mA in

pin 2 - negative diode in, also connected to arduino pin

pin 3 - positive end of diode, also connected to gnd

pin 4 - going to motor

ok i do have diodes across all my coils and i just tested them and they work. i desoldered two relays and now the circuit works. so i'm going to replace those relays and see if it works again. any other ideas? thanks so much for all the replies!

hello,

I am trying to reverse the polarity of a motor using 4 little 5v SPST reed relays (because they're quiet). I built up a circuit with 4 relays in four arduino pins....two that are positive, ground and two that are ground, positive. I built the circuit, using diodes across the relay coils and everything. I was powering the motor separately with an 8v, .5amp powersupply and was powering the arduino with USB. Everything was working fine. I took out the USB and powered the arduino using the 8v, .5amp powersupply into the Vin pin. I let it run for awhile and everything was going fine. I came back, and the powersupply was broken and the circuit didn't work any more. I tried powering the arduino and motor sperately and still nothing....really strange things are happening....when I have the PSU in, I get a normal reading, when I hook it up to the circuit board, I get no voltage coming out when it's in the power/ground rails of the circuit board.

does anyone know what could be going on here? it's strange behavior....the only thing i could think of is that the PSU wasn't regulated and was giving me more amperage than .5 and the relays were getting stuck. but i pulled them out and they are still working....do you think this circuit might work if i had a regulated PSU that was a steady .5amps as .5amps is the max current the relays can take....

these are the relays i'm using: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_1860070_-1