Tuesday, August 31, 2010


There is pretty much no heat sink on the Pololu Jrk 21v3 USB Motor Controller with Feedback. So basically that means if you try to do any kind of serious control of start/stop/speed of a real motor (say 24V / 0.3A), you will end up melting it. There isn't much in the manual about how to even mount a heat sink, the thing is so small and there is plenty of exposed solder blobs that it would be tough to do. Having made other motor controllers get seriously hot in the past using PWM control, I guess I'm not surprised.

I'm moving up to the Geckodrive G320X. The whole bottom of it is a heat sink.

Wednesday, August 18, 2010

Going servo part 2

So I went ahead and purchased:

Tohoko Ricoh Type 7K00011 Servo Motor (whose technical details are in this document)

and to power it all: 24VDC @ 6.5A power supply.

I suspect this is way overkill for a fan, but it should be interesting to enter the world of servomotors.

Wednesday, August 11, 2010

Going Servo

So I have this desire to redo "Breath" using a servomotor to accurately actuate breath strength, rather than just on/off. Here are some options:

1) Pololu has a 3A Motor Controller with feedback($49.95). It works with a tach on a motor, and you can interrogate it over USB to control/configure it and get all kinds of neat info. It also works with TTL, PWM, and analog input for control.

2) Geckodrive G320X 20A ($114) motor controller that works with a quadrature encoder. It only accepts pulse control. This is probably great if I needed bi-directional strict control of a big expensive motor with a quadrature encoder, but is probably overkill for a fan.

3) Encodergeek's Model 100 3A ($99) motor controller. It isn't clear to me if it works with tach or quadrature encoders (though he sells quadrature encoders, so you'd think it would work with them) and does pulse and analog control. He also sells his own 3A motors with encoders for $40, as well as compatible gearboxes, encoder wheels, encoders.

Also I'd need a motor. A case fan needs to spin up to 2K-3K RPM or so. I saw some motors with tach encoders over at All Electronics in Van Nuys, maybe I'll check there and see what they have.

Wednesday, August 04, 2010


Here are some quick updates:

My Breath OSC Interface App is now on iTunes, hurrah!

I am picking up from three years ago on DogCeleration. Especially now that my beagles are in LA and just had their first movie released, I thought they should join the art world as world. They key to interfacing with the Bluetooth BlueRadios on OS X is Zterm, just remember to hit shift when you run it to choose the right connection.

Alberto Gaitán recently mentioned the existance of Pachube, "realtime sensor, energy and environment data", which includes wind sensor data. Which would be a great source for "wind over IP" to a servomotor driven fan.

I also recently picked up a Mini2440, which is an awesome Linux-capable ARM-based SBC with Ethernet, serial ports, A/D converters, a cheap camera, and much more! I am still exploring it, but it seems pretty cool.