Partner: Manan
When we started brainstorming for the kinetic project, the shop staff happened to be taking a metal lathe apart. We were able to salvage parts of the machine and wanted to put gears together, so that cranking the main gear will indicate the amount of power it’s producing on the voltmeter.
Components salvaged
Measurements for fitting the wheel with the knob on the inside
A lot of time spent in the shop later…
It turns perfectly!! No friction, no belt slipping, no misfit teeth ~chef's kiss~
It turns perfectly!! No friction, no belt slipping, no misfit teeth ~chef's kiss~
The most difficult part of fabrication was making sure that the wheels can fit in a matter that makes movement possible. It took some trial and error, and very rudimentary construction of the wooden blocks. Manan had the great idea of screwing our stepper motor into the body, so that it’s secured and it serves as the end of the group of wheels.
Admittedly, our gear ratio is extremely ineffective (roughly 4rpm by hand → 1rpm on the motor), but at this point we have already committed to the idea and didn’t want to make significant changes to the engineering of the project. I was joking that Dre and Zeal’s project with the bike wheel can be the example, while ours can be the anti-example.
Manan is a rockstar! He hooked our device to the oscilloscope, and with some experimenting, we were able to detect that our Vmax is around 7.5V. We think it’s a fair next step to make a voltmeter with a maximum voltage reading of ~9V (in case anyone’s particularly strong and tempted to blow up our LEDs).
We based our circuit on this YouTube video:
https://www.youtube.com/watch?v=cjYqBUbPLUA
We thought making the voltmeter would be straightforward, but it turns out to be rather complicated!
My sample circuit powered by a desktop power supply, running with 3.0~3.2V, 20mA green LEDs — by the time the last LED lights up, the voltage is around 14V
680 voltage: 3v, 5v, 8v, 12v, 14v
| 1k | 14v |
|---|---|
| 680 | also 14v?? |