Emergency Stop Button Required?

[DanL]

Here's a pic of the dongle I made this year:
http://www.chiefdelphi.com/forums/at...&postid=135152

The purpose of this was to help us during practice mode. You'll see there's a big red e-stop in the center, as well as a switch to switch between auto and manual mode. The purpose of this is to have something around to switch between auto and manual mode without turning the controller off, changing the team number, rebooting, etc. While I was doing this, I also said I might as well make an e-stop button incase something starts smoking.

This was made JUST FOR PRACTICE. At the competitions, FIRST gives big red buttons that you can press to disable your robot (and, of course, THEY toggle auto and manual mode).

If you want to make one, first look through the whitepapers for Joe Johnson's paper on how to make a yellow dongle. Then go here for the updated 2002 pinouts on the competition port. I didn't exactly follow either of those - Joe's didn't have a auto-mode option (auto was introduced this year) and the IFI one didn't have indicator LEDs. Naturally, I wanted the style points, so working with our electrical mentor, we figured out how to slap some led's, switches, and diodes together.

On a side note, the LEDs have to be powered by batteries because the controller doesn't give enough juice to power them on the +12 pin (atleast in tether mode it doesn't) - that's why we used the diodes. If you want the wiring diagram, lemme know... i'll find a copy of it, maybe make an updated whitepaper.

Also, the e-stop button is from Digikey... page 802 of the jan-apr 03 catalogue... part numbers Z1345-ND and Z1555-ND. Note that these was just the button and the e-stop label. The actual contact block (the mechanical part that does the switching) was another 5 bucks. I assume it was so relatively expensive because those are designed to handle a lot more current than was needed. So I just saved 5 bucks, found an old computer power push-button switch, and hotglued that to the button. Messy, but its hidden and it works, so thats 5 bucks in the pocket.
All together, it cost $10 - 10 bucks cheaper than Carl's switch. Actually, if you bought the full switch assembly from digikey along with the e-stop label, it would be only $15... still half as expensive as the other one. On the other hand, Digikey has that $10 surcharge if your order is under $25, so... bah, something.

Hope that helps

[edit]Don't know why the link shows up instead of the pictures... I'm using the IMG tags, but apparently Brandon disabled that option if it's CD that's hosting the image...