[Max Weisel] recently created a Peltier-based cooling/heating system that fits into a backpack. The system uses two Peltier units, each running at 91.2 watts, with computer heat sinks mounted on one side of the unit to dissipate the excessive amounts of heat generated. While he was originally trying to build a cooling backpack, the use of the Peltier units meant that the cool side would become warm when the direction of current was switched, meaning that the backpack could become a heating backpack with the flip of a switch. In order to power the two Peltier units, he uses two 12v motorcycle batteries, weighing in at around 5 pounds each. While this backpack might be a little heavy for your back, it looks promising for anyone who needs to keep things cool (or warm) on the go.
classic hacks2826 Articles
Knit Touchpad
[Plusea] made her own touchpad using some anti-static gloves and an Arduino. This proof of concept is fairly small, but the system could be scaled quite large if you could find the fabric. She cut apart the anti-static glove, mounted it and wired it to the Arduino. A special piece is made to fit over the finger that is also wired to the Arduino. The location of where she touches is determined by the resistance between the finger and each corner. Watch the video on the instructable to see how it measures.
She mentions that there are a few different ways to build it, some which would not require anything on your finger, but would use another piece mounted behind the touchpad. The method she is currently using though, would allow for the fabrick to be any size or shape, even molded around something.
How-To: Web Server On A Business Card (Part 2)
This mini web server is slightly smaller than a business card. There are a lot of tiny one-board servers out there, but this is probably the smallest you can etch and solder at home. Unlike many embedded web servers, files are stored on a PC-readable SD card, not in a difficult-to-write EEPROM. Read on for the web server design, or catch up on PIC 24F basics in the previous article: Web server on a business card (part 1).
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Arcade Button Monome: Moanonme
[Johan Larsby] built this pretty cool Monome clone. He was starting with a kit to build an Arduinome, but had issues getting his LED matrix to work correctly. After digging around in some old parts and hacking together some custom LED arcade buttons, he ended up with the Moanonme. Be sure to check out the video after the break.
Underwater ROV
[SpaceShipOne] has built this very nice looking under water ROV. It is still a work in progress, but nearly complete. This ROV is a fairly simple construction. most of the body parts are held together using zip ties. There’s no microcontroller and no custom boards. He’s using a radio control transceiver that was intended for airplanes to control some standard speed controllers and servos. For thrust, he pulled the motors out of some bilge pumps and fitted them with propellers. He’s only tested it once, but promises videos from the lake soon. He mentions [Jason Rollette] several times since [Jason] has done both simple and complex designs in the past.
Laser POV Projector
[shakirfm] sent us this LED persistence of vision (POV) laser projector that can display dot matrix style text. The laser projector contains a rotating mirror assembly and 5 lasers. We’ve covered other POV projectors,but this one is a bit different. The mirror assembly rotates using two cooling fans. Controlling on/off times of the lasers along with the mirror speed, it is able to project 8×5 dot matrix ASCII text onto a surface.
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Parts: LM317 Adjustable Voltage Regulator
Every project needs a power supply. As 3.3volt logic replaces 5volt systems, we’re reaching for the LM317 adjustable voltage regulator, rather than the classic 7805. We’ve found four different hobbyist-friendly packages for different situations.
A simple voltage divider (R1,R2) sets the LM317 output between 1.25volts and 37volts; use this handy LM317 calculator to find resistor values. The regulator does its best to maintain 1.25volts on the adjust pin (ADJ), and converts any excess voltage to heat. Not all packages are the same. Choose a part that can supply enough current for your project, but make sure the package has sufficient heat dissipation properties to burn off the difference between the input and output voltages.
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