Jan 16 Meeting Summary

[jdneal]

Thanks everyone for coming and for sharing their ideas and projects!
There were about 15 people at the meetup in total, and too many
Arduinos for me to count.

Still have to find out of the photos were posted (camera ran out of
battery, so probably didn't finish uploading pics.)

Projects:

Reto Stamm: brought a work-in-progress inverted pendulum made from
acrylic and using a potentiometer as a sensor for the pendulum. One
interesting thing that I remember about it is that it's meant to
travel on rails, I thought that was fairly unique.

Adrian Freed: brought a wide variety of Arduino boards, and various e-
textile projects including a large collection of conductive fabrics
and threads (nickle-coated kevlar even.) He gave a detailed
demonstration on how to build a conductive fabric touch pad, and
brought a textile ball inclinometer, a pressure-sensitive wearable
keyboard, among other projects and works in progress. Discussed some
interesting circuits using neon tubes, and brought some examples of
his "Bachelor Pad" neon tube controller board.
Website: http://cnmat.berkeley.edu/

Giuliano Carlini brought a work-in-progress Arduino powered auto-
balancer (inverted pendulum) robot, with a number of sensors
(gyroscope and accelerometer?) mounted on it. He mentioned it would
implement Boids algorithm, and there was some discussion of using a
Kalman filter for motion control Guiliano also brought an XMEGA based
board from AVR. (Was this the Xplain board?) Also brought a touch-
sensitive, Arduino-powered stuffed animial project. (Which will be
featured in an upcoming TechShop project class.)

I brought a Rainbowduino board from Seeedstudio and an RGB color
sensor connected to a Seeeduino that I've been working with and also
some JeeNode wireless boards.

Various bits:

JeeNode wireless Arduino, from Jee Labs (http://news.jeelabs.org/) and
available in the US from Modern Device company (http://
www.moderndevice.com/products/jeenode-kit)

Armite, ARM7 based board in Arduino shield compatible form factor.
http://www.coridiumcorp.com/ARMduino.php

Some discussion of Arduino sound synthesis, and the Open Sound Control
project.

Some info from my blog on the Li-poly phone charger battery I was
using to power the Seeduino board:
http://www.trochotron.com/2009/08/repurposing-2-li-poly-power-supply-for-microcontrollers/

[jdneal]

Ok, photos are online, starting with DSC_3764.JPG:

http://www.flickr.com/photos/techshop/page7/

and ending here at DSC_3780.JPG:

http://www.flickr.com/photos/techshop/page6/

- Joshua

[jdneal]

Oh, and a few more here, oddly out of sequence with the rest:

http://www.flickr.com/photos/techshop/page8/
From DSC_3760.JPG to DSC_3763.JPG.

- Joshua

[Thomas]

Is there a summary of the meeting available?

The gentleman that presented on e-textiles mentioned a library for producing sound on the Arduino.  Does anyone know where it can be found?

-Thom

[Joshua Neal]

For the summary, read the first message in the thread :-D (Or use the
archives if you missed it.)

Adrian just tweeted this link, I think this is what you were looking for:

http://www.adrianfreed.com/content/oscuino-arduino-osc-sketch-open-sound-control-work

- Joshua

[Thomas]

Thanks, for some reason the first message in the thread did not go to my inbox.

I searched Adrian's blog, and this example is the one I am interested in:  

http://www.adrianfreed.com/content/arduino-sketch-high-frequency-precision-sine-wave-tone-sound-synthesis

I am not familiar with timers and was trying to modify the part where they are initialized so that I can have more than one oscillator at the same time.  How would the following part of the code be modified to allow two oscillators?

void initializeTimer() {

 // Set up PWM  with Clock/256 (i.e.  31.25kHz on Arduino 16MHz;

 // and  phase accurate

  TCCR2A = _BV(COM2B1) | _BV(WGM20);

  TCCR2B = _BV(CS20);

  TIMSK2 = _BV(TOIE2);

  pinMode(PWM1_PIN,OUTPUT);

  pinMode(PWM2_PIN,OUTPUT);

}

-Thom

[jdneal]

Take a look at this page here on the Arduino wiki:

http://arduino.cc/en/Tutorial/SecretsOfArduinoPWM

I think the easiest way would be to set it up like the Phase-Correct
PWM example on that page, which uses both output compare pins on
timer2. Then you'll want to change the interrupt handler to update
both OCR2A and OCR2B (aka PWM_VALUE_DESTINATION in the example) with
different values.

- Joshua

On Jan 24, 9:08 pm, Thomas <tam...@gmail.com> wrote:
> Thanks, for some reason the first message in the thread did not go to my
> inbox.
>
> I searched Adrian's blog, and this example is the one I am interested in:
>

> http://www.adrianfreed.com/content/arduino-sketch-high-frequency-prec...

>
> I am not familiar with timers and was trying to modify the part where they
> are initialized so that I can have more than one oscillator at the same
> time.  How would the following part of the code be modified to allow two
> oscillators?
>
> void initializeTimer() {
>  // Set up PWM  with Clock/256 (i.e.  31.25kHz on Arduino 16MHz;
>  // and  phase accurate
>
>   TCCR2A = _BV(COM2B1) | _BV(WGM20);
>   TCCR2B = _BV(CS20);
>   TIMSK2 = _BV(TOIE2);
>
>   pinMode(PWM1_PIN,OUTPUT);
>   pinMode(PWM2_PIN,OUTPUT);
>
> }
>
> -Thom
>
> On Sat, Jan 23, 2010 at 11:10 PM, Joshua Neal <jdn...@gmail.com> wrote:
> > For the summary, read the first message in the thread :-D  (Or use the
> > archives if you missed it.)
>
> > Adrian just tweeted this link, I think this is what you were looking for:
>

> >http://www.adrianfreed.com/content/oscuino-arduino-osc-sketch-open-so...