02-04-2012 09:48

djshaffer

Re: pic: VEX power from 12v

im woundering what resistors you had used in this project, my team is wanting to do the same thing, Thanks!

02-04-2012 10:06

StevenB

Re: pic: VEX power from 12v

Whoa, way to revive an old thread!

The key part is a variable voltage regulator (probably an LM317T), so take a look at the datasheet to find out exactly what resistors you need. The Vex controller needs between 7.2 and 9V. You could also use a straight 9V voltage regulator, although you would probably have to order these instead of getting them from Radio Shack.

02-04-2012 13:23

JosephC

Re: pic: VEX power from 12v

Plug it into your Digital Sidecar, that's all we did.

02-04-2012 14:36

Alan Anderson

Re: pic: VEX power from 12v

There were no Digital Sidecars in 2006.

02-04-2012 17:51

AlexH

Re: pic: VEX power from 12v

the vextrollers do work at 12v. just have to be careful with the amp draw at the higher voltage.

02-04-2012 19:54

DonRotolo

Re: pic: VEX power from 12v

The LM317T also really prefers a heat sink for anything more than about 1/2 Amp, and a large capacitor (~10 uF) at the output will help it as well. Again the datasheet is your friend.

05-05-2012 02:40

Steven Sigley

Re: pic: VEX power from 12v

I made one of these based on the information in this thread and a data sheet from I believe it was TI. I've drawn up a rough sketch of what the circuit looks like and figured I'd share it. Works great for us and outputs 7.2 Volts, just about what the Vex computer would love to have.
Here's the rough schematic I made:

05-05-2012 02:53

Steven Sigley

Re: pic: VEX power from 12v

http://www.vexrobotics.com/products/.../276-2170.html

At least on the old computer it says that with motors and servos the computer should draw about 62 mA. I have a heatsink on the LM317 on the converter I made but after testing it and reading this bit of information, i think it may be unnecessary.