Parallax Pico Servos

StevenL1124

Hi,
My team and I are working on a senior design project which uses parallax pico servos coupled with BASIC stamp programming language. Unfortunately, my programming experience is limited to what I have learned using the the continuous rotation servos which come with the BOE-Bot, and I have no idea how to program these new pico servos. I tired looking through example code parallax posts with other programming kits, but had no luck. Can anyone point me towards basic programming syntax for these pico servos? I only need them for a pretty basic task, so hints or examples would be very helpful.

THANKS

Mike Green

From a programming standpoint, there is no difference between pico servos and any other servo. They respond to pulses between 1ms and 2ms in width, repeated about 50 times a second. Some servos will respond to pulses as narrow as 0.5ms and as wide as 2.5ms.

The only difference (except size and power drain) is that continuous motion servos' speed and direction is set by the pulse width while standard servos (including pico servos) position themselves to a position set by the pulse width.

Phil Pilgrim (PhiPi)

The Pico servos (and other standard servos) use the same PULSOUT commands that the continuous rotation servos do. The only difference is that, instead of commanding a velocity, the pulse widths command an absolute rotational position.

-Phil

Kevin Wood

The Boe-Bot manual shows how the continuous rotation servos work. You can view normal servos in the What's a Microcontroller manual: www.parallax.com/tabid/535/Default.aspx.

StevenL1124

okay, so for example.... If i wanted to hold at some reference position (the origin) I would use the code like:


DO
PULSOUT 14, 750
PAUSE 20
LOOP

is that right? assuming my servo were off pin 14...
these servos are limited to roughly 180 degrees of travel, would this place me in the middle of this range?

Phil Pilgrim (PhiPi)

Yes and yes.

-Phil

StevenL1124

thanks so much for your help guys, I really appreciate it.