I’m creating an art project with slowly-rotating ~6" cylinders with led lights inside of them. I’ll probably be making a dozen or more of these units, so I’d like to find a fairly simple cost-effective solution that meets these goals:
slow variable-speed rotation (1RPM-20RPM)
low power consumption (run off a battery)
can be controlled from Arduino or other to respond to inputs
I’ve been doing the Arduino inventor’s kit experiments and researching the different kinds of available motors, but I’m not sure which of the following options would be best for my project:
hobby motor (ROB-10171) - cheap, but would need to reduce speed considerably (with gears or belt) and PWM speed control is limited
micro gear motor (ROB-12285) - would still need to reduce speed with gears or belt and may need motor driver for control
stepper motor (ROB-10551) - reversibility and control are nice, but the 7.5 degree stride may not be very smooth and others are 3x the cost per unit
dual motor gearbox (ROB-00319) - more complex than I need and still requires motor driver
Have I overlooked any other solutions? Does anyone have any suggestions? I’m an experienced software engineer, woodworker, and tinkerer, but a newby to electronics. Thanks in advance.
Are you going to have some microcontroller (MCU) running each piece ? If so, what ? (what flavor of Arduino)
How many cylinders are in each piece ? Do they all rotate at the same speed ? At the same ratio of speeds ? Do they need to run independently ? Reverse rotation ? Are they easily rotated or do you need a lot of torque ?
What voltage do you have to run the motor(s) off of ?
Yes, I assumed that I would need some microcontroller for each piece. I’ve been experimenting with the Arduino Uno, but if I could run everything off a simpler platform like the Pro Mini 328, that would be even better. I figured the MCU choice would be somewhat dictated by my motor controller needs.
Each piece is one cylinder. Each cylinder will be easy to rotate (think of a large coffee can on a thin axel). Each cylinder could rotate at a different speed and change speed/direction on its own. I’d prefer that each one be independent so I don’t have to chain them to a single controller or power source, but if there’s an obvious economy to running several co-located cylinders off a single controller, I’d be willing to consider it.
The power source will likely be 9v or 12v, to drive the LEDs.
Hard to say. You could use a gearmotor and an H-bridge and PWM it as needed or use a small stepper and driver and microstep it as needed. In both cases you’ll still have to drive the cylinder from the motor shaft, another chance for gear reduction. A simple L293D (or equivalent) driver for the gearmotor. And you can find really cheap steppers+drivers on FleaBay. I might lean towards the stepper as gears will eventually wear out and become noisy.