I am designing a RC car to imitate a cow in order to train horses for an event called cutting. Basically a single cow runs left and right and the horse mirrors what the cow does.
What I have so far is a typical hobby-grade RC (Axial Wraith) that uses a 2.4GHz pistol-grip transmitter and receiver. The receiver directly controls the steering servo. The receiver also controls the electronic speed control which in turn controls the brushless DC motor.
The first stage of the project has been getting the chassis and motor fine tuned so that the RC is physically capable of what I need it to do. For the most part I drive the car forward at varying speeds, stop, reverse at varying speeds, stop. Repeat. Sometimes I drive it on an arc rather than a straight line. All of this is done in pretty uneven sand. Stage one is more or less complete.
Stage two is to come up with a less obtrusive transmitter. At the moment I ride the horse with the reins in one hand and I run the transmitter with the other. I would like to be able to ride with one rein in each hand. I'm thinking that I could use a small joystick transmitter (like a Wii nunchuck) in one hand and control a rein with that same hand. Googling that idea is what introduced me to Arduino and it seems like there are a variety of ways that this can be done.
Stage 3 (if I get that far) would be to have proximity or range finder sensors on the RC to make it autonomous and "react" to the relative position of the horse. On a live cow, the closer the horse gets to the cow the faster the cow moves. If the horse is to the right of centre of the cow, the cow goes left and vice versa. Again from what I can see this seems very doable.
So I think I need to have an Arduino interpret the output from the nunchuck and send the output to an xbee and those components will be with me on the horse. Another Arduino/xbee on the RC will receive that data and also interpret data from onboard range finder sensors. The onboard Arduino will then directly control the steering servo and control the motor through a motor control shield or the existing electronic speed control.
Is this possible? Are there any pitfalls I should be aware of or any shortcuts I don't know about?
Another feature that would be great is if the RC could hold its course even when it gets bounced around in the sand. Maybe using an accelorometer to measure how far it bounced and countersteering that much?
I appreciate any and all help!