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For this Cornell ECE 5760 Hand Tracking Pong project Hanting Lu and Kedari Elety have connected a camera to an FPGA, the image is down sampled so that it is only looking at a 40 X 30 image to determine how the players are moving. “The NTSC video signal from the camera is stored in the SDRAM at the rate of the TV Decoder Line clock (TD_CLK). Data is read from the SDRAM each time the VGA requests data. The data from the SDRAM is in YUV format which needs to be converted to RGB before sending it to the VGA. For skin detection, we added a filter at this converting module level such that in addition to the R,G and B values, the module also outputs a one bit binary 1 if it corresponds to a skin pixel. Else, zero. By doing this, the output on the VGA is now white corresponding to skin pixels and black otherwise.”
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Most of us toss away our car and boat batteries when they no longer start our vehicle in the winter. Most of these batteries are now advertised as maintenance free lead acid, even though the electrolyte often still dries out. Youtube user Redicety12 shows us how you can bring them back to life by cracking the tops off the battery, dumping out all of the old electrolyte out, rinsing with a baking soda and water solution, then a second water only solution. Now that it is clean he fills it with alum water. After a trickle charge the battery is brought back to life. Probably is not as good as new but will probably give you some additional usable life.
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Dimitri, Frank, Kevin and Robin from Eectronique have sent in some details of a project that they have been working on. They had an old early 90′s LED matrix sign and wanted to make it work with a Raspberry Pi. The circuit layout is what you would expect from that era. Read More: Old Display Reverse Engineered to work with a Raspberry Pi “I was able to retreive an old (1992 !) bus display (the thing that says the next stops on the buses). It was old: unknown protocol, unknown wiring, not fast at all, etc.. I brought it to the university (uni of Geneva), and, with some friends, we decided to hack it. As we had some RPi’s laying around, we thought it would be cool to hack the display and connect-it to the RPi: we could then be able to display the date, next bus stops, some jokes, etc . The display itself is very old school: all the cathodes pixels/led on a line are connected to shift-registers (daisy chained). then, the anodes of the LEDs of each line are connected to the transistors. So to display a string, you first have to send the first line, then power the first transistor. Then clear the line, send back the second one, power the second transitor, etc.. Is was very simple to connect to the RPi as the signal is only going from the RPi to the display, so we didn’t had to do voltage-level conversions. We then wrote some software (in C: the git repo is on the website), to handle the protocol, the sending and a deamon that listens on a pipe.” |
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Rich Olson shows us how he was able to laser etch the trace pattern onto some copper clad PCB using his laser cutter so that he could later chemical etch the unwanted copper away. I have tried something similar and was not successful since I was not able to line up the front and back of the PCB well enough for pads and vias to work. Rich uses a jig to allow the PCB to be flipped and slotted into the correct orientation without any manual hand eye fiddling. The final etch is done using Copper Chloride in Aqueous Hydrochloric Acid which is a cheap alternative to ferric chloride. |
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You can purchase some macro lenses for your phone camera but with a bit of work and a spare LED lens you can make your own. Only thing to make sure is that the LED lens is high quality so that there aren’t any bubbles or other imperfections in it which would cause image distortion. ASCAS shows us how it is done in his LED Lens converted to Macro Photography Lens Instructable.
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With this hack you will be able to Hack a Sigma Lens to operate with Canon Cameras. The lens being demonstrated is an older lens and the camera that it is being adapted for is a DSLR. The issue is that the signals from the DSLR for adjusting the aperture of the lens are not recognized by the lens. By adding a small microcontroller in the mix, the camera can now talk to the microcontroller and the microcontroller can now control the lens appropriately. The system is not entirely stable so this doesn’t sound like a solution for professionals but for a hobbyist that wants to get some use out of an old lens this might be just the hack needed. Via: Hackaday “Components required
Tools required
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Check out this cool 3D Printed Stepper Motor that Christopher Hawkins made. You can see in the video that it can move quite quickly and not loose any steps. This design would be idea to teach how stepper motors work. Via: Hack a Day “This is a programmable stepper motor and driver that I made out of some nails, magnet wire, neodymium magnets, a digispark microcontroller, and a 3D printed piece that I designed around these things. My goal was to make something about the size of a business card that moved. You can’t exactly fit it in your wallet but it does indeed move. It just a first draft- there’s lots of room for improvement. It has a step angle of 15 degrees (although the way I’m driving it, it is 7.5 degrees.)”
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