I made it through the perfunctory “hello world” with a blinking light.
First test: car door lock actuator
I got development on music machines started in earnest by testing a car door lock actuator. These are interesting gadgets because they have a plunger that moves in and out with a nice amount of torque, which would be great for mechanical drums. And at under $10, they’re cheap, too!
I hooked mine up to a hacked-up 12 volt power supply, and switched it with a relay on a nice little board controlled by the Arduino.
With this setup, I’ve got a plunger pushing out of a motor gun on command. The plunger could be retracted by reversing the polarity, but I decided to keep things simple on day one and just push it back myself.
Good properties for music
- Relatively long stroke
- Plenty of torque
- Resists some movement caused by external force, even when powered down
Less desirable properties
- Slow to extend or retract completely
- Noisy gears
- Bulky enclosure
- Large range of motion and high torque
- Simple on/off motion: don’t need quick or repeated response, or varying force
- Loud or big instruments