Misc Hacks

4181 Articles

VU Meter Made With An LM3915

July 2, 2008 by 17 Comments


So here’s the situation: you have an audio device, maybe a boombox, perhaps one you built yourself, but it has no VU meter. No problem; building a VU meter is easy with these instructions from [Joe].

You’ll need either an LM3915 or LM3916 chip, a couple of bread boards, two audio jacks, ten LEDs, and a few other components. Wire them all together per the schematic, then plug an audio source into the input jack. You can plug your speakers or output device into the output jack, and you’re done. Keep in mind that LM3916s switch negative, so positive to positive wiring from LEDs to the bread board will be necessary. The wiring on [Joe]’s version is a bit convoluted, but it can be cleaned up on yours if you take the time. Video embedded below.

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Age Verification Cameras Easily Fooled

July 2, 2008 by 18 Comments


Nice try, Fujitaka. They manufacture cigarette vending machines in Japan, and were all set to roll out a new system of age verification cameras on their machines, which would scan the face of the buyer to look for sagging skin, wrinkles, age spots, and other signs of legal smoking age. The system is easily circumvented, however: people with a photo of an older person clipped from a magazine can fool the machine by simply showing the photo instead of their own faces.

Another aspect to Japan’s cigarette control is the Taspo card, which is an age verified ID issued to smokers of legal age or older (20 years old is the legal age in Japan). Taspo cards are required for over the counter purchases, and the majority of vending machines require them as well. Relatively few machines are outfitted with face recognition systems, but many more are set to ship in the coming months. Fujitaka claims they are working on a solution by improving the face recognition software, but we think it would be a lot easier to simply check the background of the image. Since the camera is static and always pointed in one direction, the portraits it captures should always have the same background. Someone please tell Fujitaka we just saved them a boatload of R&D money… until Guy Fawkes masks become more popular.

Another Helping Hand For The Work Bench

July 2, 2008 by 3 Comments


We like clever work bench accessories; especially the kind that make our projects that much easier. [rstraugh] put up his version of the ubiquitous helping hands: thirdhand++. The arms are made from modular coolant tubing that’s made for machine tools. With the basic arms in place, he created several attachments – like this PCB holder, a LCD holder, the usual alligator clips and even an oscilloscope probe holder.

Electric Bandages

July 2, 2008 by 2 Comments


Silverleaf Medical products has created an electric wound dressing that staves off infection by killing microbes in an open wound and preventing other germs from getting in.

They call it the CMB Antimicrobial Wound Dressing, and it is made of polyester fabric woven with a proprietary material called Prosit. When the bandage is moistened, the Prosit generates a low voltage, killing germs in the wound. One of these bandages can be worn for 3 days at a time, and their clinical trials indicate that they are highly effective in treating infected wounds. Take a look at their brochure (PDF file) for some informative and stomach-turning before and after photos.

[via Medgadget]

LED Painter

July 1, 2008 by 8 Comments


The people at Brilldea have come up with LED Painter, a 16-channel RGB LED controller capable of controlling up to 48 independent LEDs. It uses a Texas Instrument TLC5940 to control the LEDs and can be connected to more LED Painter boards, creating a large array of RGB lights. The TLC5940 itself has been modified to make connecting independent LEDs easier.

The team strung together nine of these along with a Propeller-based controller called a Prop Blade and fitted the lights into three windows with semi-opaque glass to create a display of dancing randomized RGB lights. If all the dancing lights have inspired you, the TLC5940s are fairly inexpensive, but you’ll need both through-hole devices and some SMT components to get if off the ground.

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TB-303 Teardown

June 30, 2008 by 4 Comments


Flickr member and owner of awesome stuff [Firegroove] brought us a teardown of a Roland TR-909 drum machine before, and now he brings us a new photoset of a TB-303 synth teardown. The machines comprise two thirds of the holy trinity of 80’s electronic music machines, so look after the break for more photos.

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