[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.
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[Ito-Brazil] pointed out N-Labs simple current limiter for stepper motors. A current limiting system will let you run stepper motors at higher speeds, with greater torque and efficiency without overheating. This particular design is meant to improve upon the common L/R and Chopper drivers. It can handle high voltages without using large resistors and is high performance without using expensive ICs.
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[Mac Cody] wanted to add a digital compass to his robot. He thought the idea of the affordable Dinsmore 1490 digital compass using 4bits to transmit 3bits of data was ridiculous. He decided to build his own 16 point digital compass instead. The compass has four pairs of IRLEDs that reflect off of a gray code wheel. Each concentric track on the wheel represents 1 bit. He ran into some trouble when the compass magnets were being thrown off by the component leads. It just required a bit of tweaking to get right. Mac isn’t sure that this is the most cost effective way to gain one more bit of precision, but he did enjoy the experience and gained a greater appreciation for commercial units.
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Reading [computerguru365]’s infrared security camera build you may wonder “Why did he build it like that?” Well, he was working with what he had. He disassembled a webcam and removed the IR filter (sound familiar?). He mounted it in a stripped power supply case with the zoom assembly pulled from an old camcorder. The zoom control was wired to the back of the box. The final addition was an IR array to the front. You could probably buy a better product off the shelf, but if you’ve already got the parts, why not
[deniska] is working on a real-time GPS map viewing application. The application will determine the location using this simple PSP GPS setup. Deniska modified the connector on a $100 Holux GPS unit so that it could be read through the PSP remote port. A test program that works in kernel mode is provided. Deniska notes that this will probably work with older (read: cheaper) Holux units as well.
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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.
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Our friend [Markie] keeps insisting on dragging all of his old tech into the new millennium. In his recent article about cramming a non-airport WiFi card in his old iBook he hinted at another wireless project coming up. Well here it is: a wireless eMate. eMates were sold to the education sector as durable computers for classroom use. Markie had to build a serial cable to transfer the necessary software to the machine. With only 3MB of RAM and a 25MHz processor the machine isn’t up for much, but it seems to work fairly well as a terminal.
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