UK Power meter monitor

[john] sent in his version of a power meter monitor. It’s designed to monitor the blinking light on the meter to monitor the current power usage. The light flashes in proportion to the amount of power being used, so it was a matter of using a ldr/photoresistor to capture the output and feed it to the parallel port of his computer. To finish it up, he used a shell script to feed the data into MRTG.

Li-poly pwm flashlight

I was looking for some interesting ideas for using lithium polymer cells and stumbled across this diy flashlight. (It’s on geocities, so hit the cache.) Flashlights aren’t usually that interesting, but this one uses a pair of li-poly cells and a PWM signal generated by a pic controller to regulate the power to the lamp using a IRL1404 MOSFET. It still requires an external li-poly charger, but looks like a nice project to get into li-poly and PWM applications.

i2c for the fonera

La Fonera’s are getting pretty popular lately. [Lefinnois] hacked his to get i2c working. He used a 75LS05 to adapt the io levels, and some bit banging in the software to pull it off. Now the Fonera can be used for inexpensive remote monitoring via inexpensive i2c devices. Not to mention that this could provide a cheap network interface for various micro-controller projects. (I’m thinking networked thermostat for my new house.)

Interactive laser drawing (graffiti)

This hack was linked a bit back in February, but it just didn’t get a decent write up. They used this 5000 lumen projector, a zoom lens video camera and a 60mw green laser pointer to generate interactive graffiti on nearby buildings. Most of the link love focused on the show-off video. I’m surprised that nobody mentioned the most obvious use: a laser pointer reactive white board. I could have loads of fun with this and my laptop during presentations. Thanks to [Brishen] for reminding me of this one.

DIY Powered Respirator

If you like to freak out your neighbors, you’ll love this one. [jake] had a run-in with allergies in his wood shop, so he built his own positive air pressure respirator. He used a surplus gas mask, scsi squirrel cage fan, and an automotive air filter. My old TDI VW Beetle used an activated charcoal filter for the cabin – I’d suggest one of those for more effective air filtration.