Arduino and a laser

Dear friends,

I recently placed an order for some electronic parts and a friends asked me to order a laser diode. Now, he does not need it anymore so I got one piece of laser diode and an Arduino. What cool project can I do with them altogether?

All I can think of is a tripwire, but it is easy and useless enough.

What else can I do with them?

Thanks!

Use an Arduino with SD card and SimpleSDAudio library, a laser, a photodiode, amplifier and speakers.

Send the PWM output from SimpleSDAudio to the laser. Connect the photodiode to the amplifier and use the laser to transmit wireless audio across to the amplifier and speakers.

Tuttut mentioned this as an idea in his SimpleSDAudio library thread in the Audio forum and it sounds quite cool.

Laser projector! Get the Arduino to control some mirrors...

Defence against North Korean aggression.