Turning a pedal-powered tractor into a Power Wheels

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.

Comments

  1. Sci says:

    That’s a really nice simple build. Sweet even.

    (Though the music choice on the demo-video makes it feel like it’s going to be used as a tragic slow-mo flashback in the movie of either father or son’s lives.)

  2. Stefan says:

    Hi Sci,

    thank you four the comment. And regarding the music: noboy passed away. The music was choosen mainly because of two reasons: it is free, it is not rock :-)

  3. mamanoel says:

    you are the best papa ever :-) and a pretty good hacker.
    in love superfrau

  4. n0lkk says:

    LOL loved the brief “look ma no hands”moment”. I didn’t read of a dead kids switch, a good idea if one has daredevil(who looked to be a young lady even) children. :)

  5. steven-x says:

    “the tractor has a top speed of about 15 km/h, or about 10 mph; much too fast for a kid’s toy”

    Not from a kids point of view. If you saw the hills we rode our wagons on when I was I little kid, you’d wonder how we survived.

    Of course, I changed my tune once I became a parents.

    • lwatcdr says:

      I was thinking the same thing. Really 10mph is just moderate bike speed. It is a fast jog at best.
      I do hope that the 5mph top speed is from gearing it down and not a limit set on the motor controller. If it is from gearing down then that little tractor should should be just about unstoppable:)

  6. rob says:

    “If you saw the hills we rode our wagons on when I was I little kid, you’d wonder how we survived.”

    did lots of stupid crap like this and somehow came out basically unscathed. the dumbest thing i think we ever did though was to use a car hood as a sled on a hill that was about 1 1/2 miles long. i would guess we hit 50 mph easily on that thing. was really fun til you hit a rock or a bump and it launched everyone off it to rag doll to a stop. i amazed no one died. somehow i managed to make it to 17 before i ever had a broken bone, and that happened when i was on a stepstool hanging a planter for my grandma.

    anyway, this is really cool and i think i will copy it. i got my kids a couple kettler “kettcar” pedal cars off craigslist. they are really neat and very well built, but the gearing in them is only ideal for totally flat ground, which we don’t have any of.

  7. Vonskippy says:

    Really? A helmet? For 5kph?

    Apparently the snowflake generation is in full bloom.

    Amazing how for centuries kids (including my three) could play (and survive) without being bubble wrapped.

    Heaven forbid they get a small cut or a minor bump on the head (which by the way both improve their future immune systems). Or worse, learn the whole risk/reward system called “life” when mistakes are still cured with a bandaid and a popsicle.

    • Nova says:

      Really? You’re going to nitpick on him for being protective of his son, whom he just put on an electric vehicle he just made from scratch?

      What if he rides out into traffic or off into a ditch, or simply tipped over and hit a rock nearby. It’s not enclosed like a powerwheels and has a higher center of gravity with less stability.

      You’re just offering bad advice..

    • Prasinos says:

      Sorry to burst your bubble, but children have indeed died from doing dangerous activities, even in the times when we were kids.
      Just visit you nearest pediatric hospital and ask the doctors…

    • JamieWho says:

      My thought was that even the kid walking was wearing a helmet. (though, I’m guessing he was hoping for a turn on it as well.)

      I’ve got 2 kids and they request their helmets when the play on their bikes and scooters in the driveway. I don’t put an unnatural fear into them, but they do realize that a helmet does have a purpose (and they’ve fallen enough to know that it can hurt).

      Great build. I would have liked to see it be a moped-like design so that you could keep the pedals and have battery power. That might have been too complicated though.

    • John R says:

      My kids were having a fight, and one took off her helmet, and threw it at the other, her momentum knocked her off her bike and onto the driveway. 42 stitches later, and 6 months in the hospital getting her speech back, and learning how to walk again. Brain injuries are not laughing matters. I don’t see the parent as overprotective at all, but a realist. Do what you want with your child, but kudos for the parent.

    • Richard says:

      I grew up in the days before helments, and I survived. But one of my 4th grade classmates didn’t. He had a minor bike fall and hit his head on rocky ground. Rode home, told his parents he “felt funny”, passed out and never regained consciousness. He died of a brain hemmorage that almost certainly wouldn’t have happened if he’d worn a helmet. He’s not here to speak on behalf of helmets, but I’ll never forget his lesson.

      I’m a parent now, and my kids have worn helmets all the time, even on tricycles going at sub-walking speed. I’m not seriously afraid of them getting injured on a tricycle, but I want the helmet habit to be thoroughly ingrained in them, so that by the time they’re old enough to go fast enough to hurt themselves, there’s no question they’ll be wearing a helmet.

  8. DivePeak says:

    When you go out one day and see it doing 15 km/h you’ll know you’ve passed on the hacker gene…

  9. arachnidster says:

    Wow, 250W? I’m guessing the max speed is down to the gearing or the current limit on the controller, not the motor – 250W motors are standard in electric assist on full size bicycles.

    • Pilotgeek says:

      I thought that too, 250 watts is completely overkill, as is running a 24v setup. I would expect 12v with a 100w motor, if that. Many power-wheels toys run off dual 550 size motors, one for each rear wheel.

  10. Nardella says:

    I would suggest watching your child carefully for when they take their eyes off the road warning them not to do this, and if they ignore have them run over your foot. Should help them to learn to watch where they are going.

  11. RobinJood says:

    Very cool, the kid seems to like it a lot. This is one of the great things about having a kid; there’s lots of fun projects you can do that has the side benefit of everyone saying you’re a great dad.

  12. Jack says:

    A remote control would also come handy :-)

  13. FartFac3 says:

    how many miles can this go before recharge? if it is less than 200, it is useless as a commuter vehicle. I need something to get me to and from work without having to recharge all night every night

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