Homemade resitor

[Teched3]

What does your minibot weigh?

Originally Posted by Mr V

Well our robot does back drive so we aren't using a 4 way. Unfortunately the rules changed a couple of times so there is lots of confusion over this issue. So they do allow pretty much any sw designed for wall box mounting to 2-way, the most common sw, as well as 3 and 4-way switches are legal.
To cloud things even more household wiring sw terminology is different from other types of wiring terminology. Basicallly in household switches the # before the -way refers to the number of terminals.


To wire it to provide "reverse" to one motor and brake to the other:

A 4-way switch has 2 black color and 2 brass color terminals, so we'll call them bl1, bl2, br1, and br2. Connect B+ to bl1 and B- to bl2. Connect forward + for motor a and b to br1 connect motor forward - for motor a to br 2 and motor forward - to bl2.

In sw position 1 terminal bl1 is connected to br1 and bl2 is connected to br2. Flip the sw to position 2 and bl1 connects to br2 and bl2 connects to br1. So in 1 position both motors are powered forward and in the other position motor a is powered reversed and both motor b leads are connected together which just so happens to be also connected to battery - which plays no part in that circuit. both of the brake motor leads could just as well be connected to battery +, and it would still work the same.

However to have a minibot that doesn't back drive it needs to have a high effective gear reduction and be very light.