suggestion

[reza raad]

Hi,

I think it is better to directly use digital pins of Arduino as signal pins for servos. by this way it draws  a little Amp in compare with analog pins.

best Regards

Reza

[vorpalrobotics]

Hello,

Digital pins are fine if you only have two or three servos. If you try more than that, what you'll find is that you get a lot of noise and jerking from the servos because the arduino timers are not high enough resolution to really do a good job with the servo signal (and I think you get too much crosstalk between signals). You should try to use pwm capable pins first of course but in my experience you still get issues with smoothness of operation.

Going past 3 or 4 servos you really should use a servo driver to get cleaner operation.

-Steve P.

[reza raad]

Thanks for your quick respond. but I have made 12 DOF 4 leg spider with 12 servos, that work good with only one 3.7v battery. But I have problem by hexapod as you can see in movie attached

[vorpalrobotics]

Hello,

It's really hard for me to debug this without full information on what you're doing. This is a very different setup from our hexapod project (different servos, different battery, etc.) The battery may not be able to produce enough amps to handle that number of servos, for example, but I don't know exactly what battery you're using (voltage is only one of the variables). I'm not sure what software you're using, or what is supposed to be happening in that video as opposed to what is actually happening. 

Hexapod robots have very specific requirements, you would need to do calculations to figure out what size battery (in terms of volts and amps delivered), how much torque each servo can produce vs. how much weight they are expected to carry, etc. We did extensive calculations before we built our first prototype just to get in the right ballpark of a working solution, then spent another two thousand hours optimizing the design. It's fun to just wing it with some parts, but results may be slow in coming, at least with something as complex as a hexapod.