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Re: Controlling Servos with a Pi

Posted: Thu Nov 03, 2011 9:43 pm
by ChrisCwmbran
Hi guys,

Is there anyone on here who would be able to give me some advice on what extra hardware I would need to achieve control of servo motors etc for a project relating to photography I have in mind. I have written a short document which explains what I am trying to achieve, so if you have the right kind of experience and can spare time to give it a quick read (its a couple of pages long) please drop me a message.

Thanks for taking the time to read this guys,

Chris.

Re: Controlling Servos with a Pi

Posted: Fri Nov 04, 2011 12:26 pm
by slurp
Looking at the wiki on GPIO I2C, I2S & SPI you'll have a few options depending on your choice of interface.

Analougue servos require regular pulses with a width proportional to the angle required - approx 5v signal (I can't comment on digital servos). You could provide suitable buffers or level shifters to the GPIO and drive directly or use a small micro controller such as a PICAXE as a slave using SPI or I2C interfaces.

The items of interest on the R-Pi side will be the I/O layout (& connector), the voltage and current limits, as well as programming or driver info to help you programming. PICAXE is well documented and supported - also aimed at the educational (& hacker) markets.

Best regards,
Colin

Re: Controlling Servos with a Pi

Posted: Mon Nov 28, 2011 10:58 pm
by glenn66
I've driven model radio servos directly from a PIC (16F84) with no real bother so I'd endorse what Colin has said and use a PIC set up as an I2C slave to run the servos.

Re: Controlling Servos with a Pi

Posted: Tue Nov 29, 2011 1:34 pm
by skirkpatrick
If you want an off-the-shelf solution, costing more of course, you can try:

http://www.phidgets.com/produc.....ategory=11
http://www.sparkfun.com/categories/179