Minimalist LED light detecting candle

Our flickering LED circuit combined two known circuit, and certainly wasn’t graceful because of it. [sprite_tm] saw quite a few areas where the circuit could be reduced. He ended up taking it down to just two LEDs, a battery, and an ATtiny13. The first step was getting rid of the current limiting resistors. The datasheet shows that with a 3V supply the AVR will limit the current well below the maximum current. The light sensor was removed next. [sprite_tm] referenced an earlier post on sensing with LEDs. He measures the voltage across one of the LEDs while it is off to see how much light is hitting it. The current draw while on is 10mA and 50uA while off.

Getting root on the G1

If you’ve been holding off on a T-Mobile G1 purchase because you didn’t like the apparent user restrictions, there’s some good news. The Android powered phone comes with an easy button for getting root. Install a terminal app and you can manually start the telnetd service. All that’s left is telenetting into the device and it’ll give you root level access.

Arduino wireless rotating POV

got an old cdrom and an Arduino laying around? Why not make it into a spinning POV display. It was built using parts from a floppy drive and a cdrom, as well as an Arduino and a small wireless transceiver. Using an IR sensor to detect rotations, the Arduino sends data to the LEDs. The wireless is used when sending new messages to the device. The link is in Spanish, so here’s the Google Translation.

[via Hacked Gadgets]

LCD that scans fingerprints


AU Optronics Corp has unveiled a new LCD panel that doubles as a fingerprint scanner. Each pixel is equipped with 4 optical sensors, so a 320×240 screen would have a scanning resolution of 640×480. They have also experimented with different sensors, such as UV. You can see an LCD panel that detects and displays the UV index above. Why did they use a secondary display to show the data though?

[via Gearlog]