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1  Forum 2005-2010 (read only) / Development / Re: new wireless comms module on: June 01, 2009, 02:20:21 am
Am I correct in thinking that this library would not work with 315MHz modules?
2  Forum 2005-2010 (read only) / Bugs & Suggestions / Re: Diecimila resets easily when controlling a motor on: May 31, 2009, 03:06:02 am
After following a short lesson on de-coupling and implementing the lesson learnt, the electrical noise seems to be a lot better. I still can't run both DC motors on full speed when powering the Arduino and motors via USB. But when I use a LiPo battery to power both, the motors go up to full rev perfectly.

Might try servos next project smiley
3  Forum 2005-2010 (read only) / Bugs & Suggestions / Re: Diecimila resets easily when controlling a motor on: May 30, 2009, 08:39:58 pm
Just wanted to chime in and say that I have similar problems with an Arduino Mega and the Tamiya 70097 dual motor. I've it hooked up to a TB6612FNG motor driver from Pololu.

I'm also a total electronics noob, though. So I'm going to take the wise advice and buy a stack of caps, see if that solves the issue.

I can definitely say that if I hook up the motors to a battery and power the Arduino via USB, that the reset takes a lot longer to kick in and I can actually get the motors to spin for several minutes.

Sounds like motor noise from what I've read.

I'll report back.
4  Forum 2005-2010 (read only) / Interfacing / Re: Testing RF links on: August 17, 2009, 05:59:00 am
Hey Wolfgang,

No, I didn't change anything else. Mind you that I did have conflicts with a Wii Nunchuck library at some point, and it took me a fair amount of time to realise that.

Some good things to do when debugging are:

- set up a test file with nothing in it but the TX/RX code, so as to not cause any conflicts
- try savitch's code he posted in this thread together with a graphing solution, like the Graph example that comes with Arduino - if you look at the receiving end in Processing, you should see steady patterns when you are transmitting - then you'll know that at least your RF links are working - when you stop transmitting you should see a very noisy graph
- put a blinking LED on the receiver side when something is received, rather than debugging to the Serial monitor - that's the most basic and most reliable way to debug - once that works, you can try Serial monitoring

Hmm that's all I can think of for now. You're not in the vicinity of Wellington, NZ are you? Because if so I could possibly give you a hand in person.
5  Forum 2005-2010 (read only) / Interfacing / Re: Testing RF links on: June 05, 2009, 03:04:39 am
Hi again, I've gotten further. I've now gone back to VirtualWire and it does indeed work just fine with these modules. Thanks Mike McCauley for making this awesome library!

I had commented out the following line in the receiver.pde and transmitter.pde files:

vw_set_ptt_inverted(true); // Required for DR3100

But in fact this line was very important smiley The signal is indeed inverted on the receiver as savitch pointed out.

So yes. VirtualWire examples are all go. You have to add this though (assuming Arduino software version 0016):

#include <WProgram.h>

And that's before the "include <VirtualWire.h>" line. Then you can set the pin numbers in the setup() function for transmitter and receiver respectively like this:



Hope this helps smiley
6  Forum 2005-2010 (read only) / Interfacing / Re: Testing RF links on: June 02, 2009, 04:44:51 am
You guys are THE BEST!

AWOL's Arduino+Processing oscilloscope idea was a great one. It showed lots of static coming through the receiver pin while I wasn't transmitting.

Then once I started using savitch's transmitting code, the static turned into nice regular patterns.

It's alive. Alive! Thank you.
7  Forum 2005-2010 (read only) / Interfacing / Re: Testing RF links on: June 01, 2009, 03:29:45 pm
Have you try the VirtualWire lib in the playground?

Yes, I've tried VirtualWire and get no data on the receiver. If I try VirtualWire with an actual wire connection, it works.

I have the same exact RF set and notice the receiver is inverted

How did you find that out and remedy it, if I may ask? And did it mean that you weren't getting Serial.available() at the receiving end until you figured it out?
8  Forum 2005-2010 (read only) / Interfacing / Re: Testing RF links on: June 01, 2009, 06:41:03 am
Interesting, thanks. Would that graph anything even if there is nothing being transmitted, i.e. interference? That'd help in case my Tx is broken.

Any way to test the receiver? Possibly errr, sending some signal straight to the antenna? ;')
9  Forum 2005-2010 (read only) / Interfacing / Testing RF links on: June 01, 2009, 05:26:15 am

I'm trying to get the 315MHz 4800bps RF links (WRL-08947 & WRL-08945) from Sparkfun to work. If I hook up the TX of one Arduino straight to the RX of the other Arduino with wire, my tests work. After I've attached the TX to a transmitter and the RX to a receiver, my test does nothing, zip.

I've tried all the examples that I could find, including those linked from the product page and a few using SoftwareSerial to free up the Serial port for printing via USB to a computer.

I've tested with antennae, both 23.5cm long, and without antennae. The Arduinos - one Mega one Duemilanove - are sitting next to each other on the table, so antennae shouldn't be needed. I've also tried making both antennae into loops, putting one loop inside the other as a comment on the product page suggested.

I can't even get any garbled input to show up. I'm trying to pick up the signal on the Mega's Serial1 port (pin 19), and printing it to its Serial port, so that I can see anything that comes through, garbled or not.

So, I'm thinking that maybe one of the RF components isn't working properly, but how could I test that? I have a multimeter, no scope.

Hmmm. It's been a long day :')
10  Forum 2005-2010 (read only) / Interfacing / Re: Sony AM309-3 A color LCD on: June 14, 2009, 01:22:57 am
Just got one of these out of an old broken Sony DSC-P2 camera. I'd be really interested in using it with the Arduino, too!
11  Forum 2005-2010 (read only) / Interfacing / Re: Powering Arduino and servos/motors with one supply on: June 01, 2009, 06:49:05 am
I found that decoupling worked for me in this scenario. Also, I found that there wasn't enough current when using USB to power the Arduino and the motors. And this also resulted in a reset.

After decoupling and using separate power/gnd pins for the motors and the motor driver, I found that I could run from USB, if at low speed, or run perfectly at full speed off a 1100mAh LiPo battery.

Mind, I didn't do the decoupling calculations perfectly, and rather tried a few different scenarios out until one worked for me.
12  Forum 2005-2010 (read only) / Interfacing / Re: RF: when I send data, should the TX LED light up? on: June 01, 2009, 01:51:08 am
Many thanks! I'd just stumbled upon an older topic that mentioned just that. Should have searched better :')
13  Forum 2005-2010 (read only) / Interfacing / RF: when I send data, should the TX LED light up? on: June 01, 2009, 12:29:28 am
I'm testing a really simple patch that just writes a counter value to pin 1 on the Arduino Mega. If I monitor this using the Serial Monitor, the TX LED lights up and I can see the values.

However, if I turn the Serial Monitor off, the TX LED extinguishes, leaving me to wonder if I'm actually outputting anything on the TX pin?!

The reason I ask is that I'm not getting anything on a second Arduino with an RF receiver hooked up. Similarly, the RX LED on the second Arduino doesn't light up at all, even if I connect TX on Arduino 1 directly to RX on Arduino 2 using a wire.

Thanks :')

TX code

 * Simple Transmitter Code
 * This code simply counts up to 255
 * over and over.
 * (TX out of Arduino Mega is Digital Pin 1)

byte counter;

void setup(){
  Serial.begin(2400); // 2400 baud communication
  counter = 0;

void loop(){
  //send out to transmitter

RX code

 * Simple Receiver Code
 * (RX into Arduino Duemilanove is Digital Pin 0)

int incomingByte = 0;

void setup(){
  Serial.begin(2400); // baud rate

void loop(){
  // read in values, debug to computer
  if (Serial.available() > 0) {
    incomingByte =;
    Serial.println(incomingByte, DEC);
  incomingByte = 0;
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