cougar!! cougar!!
So the cougar worked!! This was my first attempt at large scale animatronics, and it shouldn't be my last. From the beginning Meredith, Mandy, and I did a lot of planning and experimentations on what we had to do to make it work. We drew up diagrams on how the cougar would work both mechanically and through software, which really helped us get an idea of what we were up against.
Early on I tested a lot of things with the motor. To make the cougar hug and un-hug, we had to reverse the motor, which meant we needed and h-bridge Initially I wanted to create my own with relays, but I mistakenly bought 9DCV relays, which totally defeated our goal of driving the motor via the arduino (which could only supply 5V max). Good thing I had ordered an h-bridge unit from solution cubed as a backup. I highly recommend this if you want to drive a decent size motor that requires a lot of amperage.
My next challenge was to mount the pulley system onto the shaft. Since the moro was from Japan, all the measurements were in metric system. Unless I went to Canada there was no way I could find parts that would fit on the shaft of the motor!! We decided to built our own pulley system. Initially we wanted to built it out of wood, but it turned out to be too difficult to fasten onto the shaft. After some advice from Mike, we started making one out of steel and wood. Metal was surprisingly easy to drill through, and in no time we had our pulley system done.
Combining the skeleton and the motor was no cake. Our designed worked fine until we added bungie cords in the back of the cougar to pull back his arms. The motor didn't have enough torque to overcome the strength of the elastics!! Meredith suggested we try panty hose, which turned out to be a life savor.
I was very surprised how well the project worked out. Despite having no experience in animatronics at all, we pulled through and created something that was enjoyable and fun to play with. Having detailed plans early on really helped us get an idea of what problems we might face, which made it so much easier when building the cougar.
Lesson learned -
1) Look for simple materials. In this case panty hose was the perfect elastic for our project.
2) Figure out how you are going to mount to the shaft of the motor early on. It requires a lot of stress testing and can not be done in a couple of days.
3) Have a lot of diodes when working with motors that needs to stop or reverse.