Raspberry Pi Forums

Hi There, I'm very new to this forum and I'm not sure where to ask my question but I'm working on a project currently at a University in Bolton and I and one of the tutors are working together to create an animatronic head controlled via a RaspberryPi. The head is already built but what i need to know or find out is can i run 14 servo's of various voltages (some with quite high torque) from a Gert board attached to a Raspberry pie. I have never used either but the tutor has and we are working on something together that might have huge potential for controlling animatronics I build in the future. Any information would be hugely appreciated .

I got one of these out of eBay/China about a year ago.

http://www.ebay.com.au/itm/16-Channels- ... 1c30538fdd
(search "16 Channels Servo Steering gear USB" or similar). It seems to be a cut-down version of a larger board available elsewhere. Software for it (a demo gui control panel) works on windows, but of course you probably want it running under RPi/linux.

After a few struggles I got it to run from a PC running debian, so presumable it will run on RPi. I simply used the board's usb/serial input controlled from serial program. Gtkterm, I think, or maybe minicom. (Minicom is available on RPi, for try-out.) I did not try the ttl/uart connection.

It is VERY picky on your sending precisely the right control sequence from your serial program. I had to read the sketchy instructions a few times over. There seems to be NO return or OK or error or echo from the device, so you are flying blind until you see it work. Once I got it working, I had several small servos running quite happily. The board is not merely a "go to position setting 60%" device. It has its own control mcu, and quite complex preprogrammed servo motions can be scripted in from your serial connection if you choose, offloading detailed control away from the PC/RPi.

Physically, the board would look to support more servo ports, but it seems to have firmware for only the 16 claimed. The apparent analog I/O functions seem to have no firmware either.

Anyway, It's cheap. It DOES seem to work. Might be worth a try. If you are wanting different power voltages for different servos, then surely the control signal for each should work from this board, and you could wire separate supply rails for your variant servos?

Hi Darklab,

Just The Rpi alone will do the trick. Just add a voltage converter in between , maybe open collector driver .

I did use pigpio with 16 leds in pwm mode.

Check this post http://www.raspberrypi.org/phpBB3/viewt ... 47#p374647

Yes it is very easy!


Or use my little cpu servo converter.http://www.raspberrypi.org/phpBB3/viewt ... +small+cpu You could use up to 15 cpus to control 60 servos.


Daniel

Thanks very much for the replies , its very much appreciated, I don't fully understand many of the abbreviations but the guy I'm working with will do i would think, I'm going to do a bit of research so i fully understand them but thank you so much, It appears that the project could be far simpler than I had first thought ,I'm going to look into these options and hopefully will be able to put something great together by the end of the project which is great.!! Jules