hacking the mindflex

Hi so I am a senior in high school and I am working on my senior project which a Theo Jansen Standbeest with the speed controlled by a mindflex dual. I have hacked the mindflex main board so that i read just the resistance going to the motor that lifts and lowers the foam ball. That is all working fine but there is a couple of buttons that need to be pressed for the board to start the motor spinning. I've been looking at a couple of threads on using transistors as a switch, then also a couple using an optoisolator. But before i go out and buy either one of those i was wondering if it actually would work for electronically pressing the buttons i need pressed. Also if it does work what transistor or optoisolator should I use and how should i wire it?

Do you own or have access to a multimeter? You need to measure the voltage and current going through those switches. If they are TTL (or TTL compatible), you might be able to drive them directly from the arduino pins.

Unless they are pushing a lot of power through those switches, you probably don't need an opto-isolator. A simple transistor will probably work just fine. This tutorial http://itp.nyu.edu/physcomp/Tutorials/HighCurrentLoads will probably tell you what you need. The transistor is the only critical part.

Um, one question: why don't you just wire the switches closed? Do you actually need them?