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1  Forum 2005-2010 (read only) / Development / Re: Arduino frequency counter on: January 22, 2011, 11:04:06 pm
It looks like you don't plan to use the internal analog comparator like the library that you reference since you already have an external one.

Also it looks like you plan to just use 2 pins and I assume 2 counters for this.

Is my understanding correct?
2  Forum 2005-2010 (read only) / Development / new open source project on: January 19, 2011, 10:07:32 pm
Hi all,

This is a one-time post to announce the creation of Arduino Doodles.
Arduino Doodles aims to be a collection of Arduino sketches and libraries that can be reused by other interested parties.
If you have a library written for a specific IC, or an interesting sketch that can be used independent of other custom hardware/shields, and you feel that it may be useful to other people this would be the perfect place to share it.

Arduino Doodles is now running code, is under active development, and is looking for both developers and testers.

Home page:


  * Arduino board
  * Arduino Software
  * occasionally some library contained in this project

Thank you,
3  Forum 2005-2010 (read only) / Development / Re: Source Documentation with doxygen? on: November 01, 2010, 09:46:58 pm
If anybody else has this problem, for me it only started to work after I set:

4  Forum 2005-2010 (read only) / Development / Re: Duemilanove engineering drawings on: September 30, 2010, 09:08:13 pm
@ Graynomad:


As I'm looking at my Arduino, the distance from the left edge to digital pin 8 is less than the distance from the left edge to pin Vin. However on the picture you posted 48.8 although shown as less is greater than 44.7. Is it possible they are not reversed by accident?
5  Forum 2005-2010 (read only) / Interfacing / Re: debugging i2c/serial problem on: August 28, 2010, 12:01:08 am
Try to power just the OLED independently from an external 5V supply. GND should be connected to arduino, OLED and external supply.

I would keep the pull-ups as they are except if there are additional pull-ups on the TPA81. We're using pull-ups in the 2k-3k range on our designs with no issues, but if you have multiple pull-ups in parallel you may have problems.

If you really want to see how the pull-ups are calculated take a look in the I2C standard:
6  Forum 2005-2010 (read only) / Interfacing / Re: Using Arduino to Digitaly Filter Audio. on: September 12, 2010, 10:22:55 am
When you say output the contents of that bin, do you mean audio output? Because you would need an IFFT (Inverse FFT) to convert back from freq to time in this case.

Did you consider just regular digital filtering ( I have tried low-pass FIR on an Arduino and it seems to work ok. You have to adjust the coefficients of the band-pass filter based on where you want it to filter.
7  Forum 2005-2010 (read only) / Interfacing / Re: Connecting a Sure 0832 to an Arduino Duemilanove on: August 27, 2010, 07:27:01 pm
First you need the datasheet of the dot matrix:
(see bottom of page)

Then look up the connector signals in the Sure datasheet and the Arduino pin numbers in the sketch code. You should connect corresponding signals with wires, and I think you can try to buy some pre-made wires on any electronics store.
8  Forum 2005-2010 (read only) / Interfacing / Re: Python error on: August 30, 2010, 09:18:58 pm
just  a thought but I usually get this message if I did not import all necessary modules. Do you have something like:

import pygame

in your code?

Is pygame in the python path. Take a look at:
9  Forum 2005-2010 (read only) / Interfacing / Re: Arduino, Nokia 6320 and connection cables on: August 26, 2010, 07:12:42 pm

maybe this will help:
10  Forum 2005-2010 (read only) / Interfacing / Re: Temperature Probe, long distance on: August 24, 2010, 10:35:56 pm
did you consider a thermocouple?
11  Forum 2005-2010 (read only) / Interfacing / Re: I2C slave receiver problem on: August 23, 2010, 09:26:14 pm
Hi all,

Turns out I've used some old scripts to control the master, everything seems to work for now.

Thanks for all your help.
12  Forum 2005-2010 (read only) / Interfacing / Re: I2C slave receiver problem on: August 21, 2010, 06:33:37 pm
No argument from me on this, but if it's not good maybe it should not be in the official Wire library examples either. The code that you see is the slave_receiver.pde with HEX added for formatting.

I'll try your suggestion to see if it makes any difference.

I'm beginning to suspect the scripts that I use to control the I2C master, but unfortunately I have to wait until Monday to ask my colleagues about them.

Thank you all for your help and quick replies.
13  Forum 2005-2010 (read only) / Interfacing / Re: I2C slave receiver problem on: August 21, 2010, 04:38:11 pm

It's basically the slave_receiver example, just modified to show the byte value in hex.


#include <Wire.h>

void setup()
  Wire.onReceive(receiveEvent); // register event
  Serial.begin(19200);           // start serial for output
  Serial.println("receive test");

void loop()

// function that executes whenever data is received from master
// this function is registered as an event, see setup()
void receiveEvent(int howMany)
  while(1 < Wire.available()) // loop through all but the last
    char c = Wire.receive(); // receive byte as a character
    Serial.println(c, HEX);         // print the character
  int x = Wire.receive();    // receive byte as an integer
  Serial.println(x, HEX);         // print the integer

I can try to capture of the iPort waveforms also, to show that it outputs correctly. We've used this device extensively with no problems, but a second check never hurts ...
14  Forum 2005-2010 (read only) / Interfacing / I2C slave receiver problem on: August 21, 2010, 10:54:43 am

I am trying to use the Wire library for I2C communication. However I have the following problem: the first byte sent by the master is reported incorrectly by the Wire library. More specific:

- if I send 0x12 from the master, I get 0x31, 0x32 on Arduino
- if I send 0x12, 0X34 from the master, I get 0x31, 0x32, 0x34 on Arduino

It looks like the first received byte is split in half and reported as ASCII codes. The master is a iPort/AFM RS232-I2C Host adapter which was extensively used in our lab and works reliably.

Did anybody notice this problem? Any suggestions are welcome.
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