Program the timer for the desired on and off times. Most light timers are not accurate enough for this use, except in a pinch, since they usually work in 10-minute increments.

The TS3001, like the TS3002, is simple to program, andaccurate. The TS3001's timer frequency is set with just one resistor while theTS3002 is set with a resistor and a capacitor.

Droplet and StackAR, developed by MIT’s Media Lab, allow users to set timers or program an Arduino using light-based communication. By pressing the tool against a screen, flashes of light can ...