This is almost exactly what I'm looking for. I want a cooler to follow me as I walk from my truck to the softball field, beach, etc. I'm an experienced licensed electrician, and a chronic tinkerer, so I can build and wire the thing easily, and I have boxes and boxes of Arduino and Raspberry Pi hardware and sensors sitting around. I simply don't have the expertise or time to code and program the thing (having twins a few years ago sort of halted my learning this stuff).
My plan is to use a 3-wheeled setup. I will either have one motor to drive the rear wheels and a servo or actuator to turn the single front wheel, or use a motor on each rear wheel and steer by stopping or slowing one motor at a time. That stuff is easy enough for me to handle, but how to make it follow me is what I'm having difficulty with. It will be used in the open and as a sort of novelty, so obstacle avoidance, complex navigation, and high speed won't be terribly necessary. I would think a beacon (IR or ultrasonic) would be the easiest thing, but I don't know how to code it. I'm trying to do this fairly cheaply, hardware-wise, but I'd gladly pay some one of you experts out there to write the code for me so I can just upload it and maybe reverse engineer the thing a bit as I learn. Thanks in advance.