Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: arrrrgon on March 30, 2011, 11:52:17 AM

Title: Adding 3 servos to $50 robot board
Post by: arrrrgon on March 30, 2011, 11:52:17 AM
If I wanted to add 3 more servo spots to the $50 robot board would I just need to add in 3 more 3 pin connectors, with each one going to one of the open ATMega pins and then connect them to the ground and 5v power bridges?
Title: Re: Adding 3 servos to $50 robot board
Post by: hopslink on March 30, 2011, 11:59:17 AM
Yes you would add extra headers in exactly the same way as the existing ones, as you describe. If you are running 5 servos then they probably want a power bus that is separate from the +5V supply for the micro.
Title: Re: Adding 3 servos to $50 robot board
Post by: arrrrgon on March 30, 2011, 01:55:44 PM
Thanks again hopslink.  That was a typo on my part, I meant the unregulated power bus.  I'm just curious, can the $50 board control 12v motors, or will a 12v battery fry the board?  I'm a bit weak on the electronics side still, but if I'm right, the 12v should just go though the unregulated bus to the motor driver and to the motor, and the 5v regulator should still protect the microcontroller.
Title: Re: Adding 3 servos to $50 robot board
Post by: Conscripted on March 30, 2011, 02:34:44 PM
if I'm right, the 12v should just go though the unregulated bus to the motor driver and to the motor, and the 5v regulator should still protect the microcontroller.

That's correct. You would need to be very careful that you didn't accidently plug something in that might be damaged by 12VDC.
Title: Re: Adding 3 servos to $50 robot board
Post by: rbtying on March 30, 2011, 03:59:46 PM
You should probably be aware that RC Servos will probably burn out at 12V: the max voltage in-spec is 6.0v, and out-of-spec usually is limited to 7.2v.  Make sure you get a separate (preferably switching) regulator for the servo power bus - if you've got a motor drive board and motors as well, you may want to only run +12v to that board (the others likely can't handle it).