This rough-looking contraption is a hand gesture controlled skateboard which [Aditya] built using parts on hand. So far the sensor for hand gestures is connected by a control wire, but he hopes to transition to an RF unit at some point in the future.
Having access to a couple of high torque brushless motors is what turned him onto the project. He hit up a couple of Mechanical Engineer friends of his to help assemble the chassis and then started on the electronics side of things. A breakout board for an ATmega16 is mounted on the corner of the deck. It monitors an accelerometer which acts as steering as well as throttle. The accelerometer had been abused in a previous project so he had to add an extra switch to bolster his available inputs. We were glad to hear that he also included a kill switch, since putting the control of those motors in the hands of a damaged accelerometer is a bit sketchy.
We remember seeing a similar trike design a few years back. That one powered a single rear wheel while this one powers two wheels and uses a caster for the third.
It’s funny that there seems to be a certain zeitgeist that is reached in projects. Before all the pieces are in place, nothing. Then after some little part or doodad hits the market or hits it at a reasonable price, there are suddenly multiple projects that people are working on. Now we have a lot of Motorized skateboard/trike/scooter/skate/personal transport projects.
I think the part that is making this explosion possible is the availability of high torque DC motors. I just wish I knew where I could find a couple.
Yeah, I know what you mean. It used to be a ridiculous amount of work to build an RGB matrix of any size. But now you can buy strands of addressable RGB pixels and boom… everyone’s working on a Daft Punk coffee table…. I need to get in on some of that action, actually!
I thought folks were tearing them out of cheap cordless drills?
The ones that he used were not from any cordless drill that I know of. He said “some very high torque BLDC motors just sitting there. They had 75KG/CM of torque each making it 150KG/cm for me. Me being only 60 KG it was enough for me.”
He’s not going to get up to 23 mph using drill motors without a transmission.
This is from Wiki:
Brushless DC electric motor (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous motors that are powered by a DC electric source via an integrated inverter/switching power supply, which produces an AC electric signal to drive the motor. In this context, AC, alternating current, does not imply a sinusoidal waveform, but rather a bi-directional current with no restriction on waveform. Additional sensors and electronics control the inverter output amplitude and waveform (and therefore percent of DC bus usage/efficiency) and frequency (i.e. rotor speed).
I don’t know what they are in. Maybe peeps are jacking the motors when grandpa parks his scooter. Who knows. I do know these suckers are not trivial to drive. They are very sweet motors and I like the fact that they don’t use rare earth minerals since they don’t have a permanent magnet. That also makes them very light weight.
Correction, they do have permanent magnets. My love just faded a little. But they are still sweet motors.
I haven’t looked for them recently, but you want to find some brushless outrunners. Hobbyking used to be the top place to find them; you could get a 1-2 HP motor the size of your fist for $50-70?
Charles’s [teamtestbot] explains it better than I ever will:
http://www.instructables.com/id/The-New-and-Improved-Brushless-Electric-Scooter-Po/step2/A-Typical-Brushless-Outrunner/
That entire instructable is gold.
Whoops. “Charles” shouldn’t be possessive in that sentence.