Back in May of 2005 I received a phone call from colleague at Colpitts Design. He was approached to build a puppet for feature film. They were looking for someone to make remote controlled robot character to play a part in an upcoming movie.
It was described as a walking biped robot about 3 feet tall and they wanted to start shooting in about 4 weeks. I would have loved to make a biped walker but we all thought it might be a bit ambitious given the time, budget and resources, so Peter and I agreed to pitch a two legged rolling robot.
After I hung up the phone I put together a lego prototype to propose a simple method of locomotion. We shot a video and sent it to the art department. The next morning we were given the go ahead to start building.
Step 1: Full scale Prototype
We started by drawing up some parts on the computer and cutting them out, while at the same time looking at various motors, gears, servos available to make this thing move. To have the tork we wanted to drive the hips and wheels we decided to use windshield wiper motors that we drove with custom made control boards and a potentiometer connected to the drive shaft to turn it into a big servo. We took off the cast gear box and machined our own to allow us to design our own mounting face as well.
For our first test we wired everything into a plugged in power supply, later that would need to be changed for something self contained.