ReturnZero published a stroboscope build:
At its heart, a stroboscope is just a rectangular wave generator hooked up to a light source. I wanted a few extra features to make it nice to use:
- Ability to set flash rate by either frequency or RPM
- Set duty cycle of output without affecting flash rate
- LCD display
– 2×16 for displaying RPM, frequency and duty (one per line, so one will be hidden at any time)
- Rotary encoder (with button) for main interface
– When button is not pressed, knob will increase/decrease the value of the selected digit
– When button is pressed, rotating knob will scroll through display digits
- Buttons for quickly halfing/doubling thirding/trebling the flash rate
– This is useful for checking that you haven’t hit on a multiple of the rotation rate
- Nice beefy output stage for switch big sets of LEDs