[Ram Sripracha] thought it was mighty odd that his new bluetooth Mighty Mouse had an LED that was constantly on when the mouse wasn’t moving. He decided to pop the case open and see what the current draw was. When the mouse is moving the LED is off and the current draw is ~.0285 amps; when the mouse has stopped the LED is on and the current draw is ~.0450 amps. He removed the LED to create a lower power bluetooth Mighty Mouse that only uses .0017 amps when not moving. So, 3.8% of the power that was originally consumed while sitting still.

Continue reading “Bluetooth Mighty Mouse Power Save Hack” →

Master modder [Jani ‘Japala’ P?? latest hack is adding an LCD screen into a mouse. The LCD is from a Nokia 6610. It fits pretty well since the controller board isn’t any larger than the screen. The controller requires adding three more wires to the mouse. These are connected to a parallel port. The screen can only show about 1 frame per second, but that is fast enough for general statistics or showing photos. It’s a really clean build. A clever trick was using a piece of plastic from the blister pack to cover the screen since it was already the same shape as the mouse.

[thanks z]

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Hack-A-Day regular [Andrew] has posted an incredibly simple game port based photogate. He uses a pair of light dependent resistors. Each one is placed inside of a ballpoint pen tube to limit ambient light on the sensor. He’s got a simple QBasic program to calculate the velocity of an object passing the sensors. You’ll have to run it inside a DOS emulator to get access to the game port under XP.

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I2C is a simple communications bus similar to 1-wire, which we’ve talked about earlier. [hnch] has built a really simple I2C parallel port interface. It’s optically isolated so you don’t have to worry about a mistake frying your computer. I2C modules already come with the Linux kernel. It will even treat temperature sensors you attach exactly like the ones you have on your motherboard so you can monitor them using ordinary software like gkrellm. There are lots of other devices that use I2C as well. [hnch] has a nerdity gallery and will gladly write up any other project you’d like information on.

Continue reading “Optically Isolated Parallel Port I2C Adapter” →

[matt] wrote me a couple weeks ago wondering how to build a robotic arm that can load and load/unload a CD or DVD from a drive. I told him about one built out of wood that I couldn’t find the link for. Matt wrote back to say he had found the Home built CD changer contraption. The design is pretty simple and uses gravity for downward movement, so you don’t have to worry about a motor slamming the head into the desk.

He also pointed out the one built by Ben out of Legos. He used it to rip his collection of CDs for his Squeezebox. You’ll remember his caller ID project from last week.

Continue reading “DIY Optical Disc Duplicator” →

[wesley mcgrew] has been playing around with Sandisk’s U3 Smart USB Drives technology. U3 is designed to make implementation of portable applications easier. The USB drive appears as a  CDROM drive and can autorun applications. Wesley has a guide for how to patch in your own CD ISO. This ties in pretty well with the dangers of USB drives that we’ve covered before (one, two) and Schneier has a recent post on USB security issues as well.

[UPDATE: [matt] pointed out a recent Security Catalyst podcast with Abe Usher on podslurping]

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[ned]’s HandySwipe is a portable magnetic card reader. It runs on 4 AA batteries and collects data from track 2 cards. It uses a PIC 16F688 and displays the card’s data on a small LCD. It can store up to 50 cards and dump them in CSV format. It will also output the raw bitstream for use with Acidus’s StripeSnoop. Ned’s project write up is pretty interesting since he covers using a logic analyzer while swiping a card and driving the LCD with only three pins using a shift register.

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