Accrochages

I started implementing a small audio library for Arduino. It uses the PWM to generate different kinds of waves:

• square
• sinus
• saw
• white noise

For the record, I found two examples of easy-to-build circuits for radio transmission:

• 1.5 V Transmitter
• FM transmitter

Stirling engines are able to produce energy using heat.

See:

• http://en.wikipedia.org/wiki/Stirling_engine
• http://www.physics.sfasu.edu/astro/courses/egr112/StirlingEngine/stirlin...
• http://www.bobblick.com/techref/projects/stirling/can/can.html

I built a small solar engine circuit from http://www.makezine.com. It basically accumulates energy from a solar panel (or another source) and once there's enough, it triggers a small motor.

Last Saturday, April 19, 2008, we took part in a roundtable on the subject of DIY, open-source and open-hardware at États Généraux des Arts Médiatiques.

I tried another program with the PIR, this time I worked on moving averages to compute the mean number of detections and the mean time people spend in front of the PIR. The goal is to use it to give to the object a deeper consciousness of its environment (ability to detect moments such as rush hours or very passing places).

I worked today on code with the PIR module (motion detection). The first objective was to detect a continuous presence. When someone passes in front of the PIR sensor and stays, say, 10 seconds in front, he will not always be moving enough so the PIR will not always output a HIGH value. If we want to calculate a presence, we thus need a strategy that "smooths" the detection.

I started fooling around with the ATtiny13 using Sam's incredible development module but found myself rapidly limited as a programmer. I wanted to use the useful functions millis(), delay(), etc. from the Arduino, which I find pretty convenient for advanced development.

So I simply got the files that I needed which can be found along with the arduino source code, in: hardware/cores/arduino/

You then have to include the right files:

#include "WProgram.h"

void setup() {
//...
}

void loop() {
//...
}

#include "main.cxx"

I managed to compile and upload AVR programs on my Mac using different tools: AVR-GCC, AVRdude and my AVRISP2 interface. I wrote a set of instructions for the Electronix people, see:

• http://wiki.dataflow.ws/Electronix/AvrIsp2OnOSX
• http://wiki.dataflow.ws/Electronix/AvrGCCProgramming