This Ruler Clock looks like it would have been tons of fun to build. It uses a few stepper motors that are driven by a motor shield that is connected to an Arduino. Nice thing about these small steppers that are used in this project is that they can be found for free everywhere you look. Next time you see one of those disposable $50 printers being tossed out because the ink refills cost more than the printer is worth think about the small steppers that are hiding inside. Scanners and floppy drives are also gold mines when hunting for free steppers.
“The brains:
- Arduino with Adafruit motorshield – This is definitely overkill, and I used this simply because I already had it. Â If you have an Arduino compatible board that isn’t otherwise gainfully employed, then it’s quite easy to whip up a circuit using L293 ICs on breadboard that will drive a couple of stepper motors. Look here:Â http://www.tigoe.net/pcomp/code/circuits/motors/stepper-motors, for circuits for driving steppers from an arduino.
- The logic/timing part of the code would be the same for all versions, but the interfacing code will be a little different.
- Any Arduino compatible board will work fine as far as I know.
- 2x Stepper motors.  I tested this will some dead cheap little steppers that have almost no torque and only 20 steps per revolution.  I paid next to nothing for them.  I also made a version with some good quality NEMA17 steppers with 400 steps per revolution.  I paid about £14 for each of those. I ended up using the cheap small steppers.
- In the Arduino code, modify the value “stepsPerRevolution” to reflect the kind of motor you have.
- You’ll also need a power supply, maybe two if you have big beefy motors.”