A while back, [Stefan] bought a pedal-powered tractor for his son. It was a fun toy, but what it really needed was an electric motor. After a fair bit of tinkering, [Stefan] turned a pedal-powered tractor into a battery-powered Power Wheels.
Before turning his son’s pedal tractor into a battery-powered ride, [Stefan] ordered a 250 Watt motor and a Pololu motor controller. After tearing out the pedal parts, the motor was attached to the tractor with a few bits of wood (giving the tractor running boards), and a bike chain was run between the rear axle and motor. A pair of small 12 Volt batteries provide all the power and a Hall effect sensor in the handlebars provides the throttle.
Right now, [Stefan] has his son’s new battery-powered tractor set to a top speed of 5 km/h, or just a little bit faster than walking speed. [Stefan] says the tractor has a top speed of about 15 km/h, or about 10 mph; much too fast for a kid’s toy. After the break there’s a video of the tractor rolling along, and [Stefan]’s son having a great time.