Roll Your Own Capacitors – High Voltage Edition

May 10, 2011 by Mike Szczys 13 Comments

[Grenadier] tipped us off about his method for building your own high-voltage capacitors. He thought the paper and foil capacitor project was a nice introduction to the concepts, but at the same time he knew he could produce a much more powerful device.

For the dielectric he is using acetate film. This is the material from which overhead transparency sheets are made. He stuck with aluminum foil for the two plates. Just roll the foil flat with a rolling-pin, use thin wire to minimize the air that will be trapped between the dielectric layers, and make sure the foil plates are at least 4cm shorter than the acetate film on each end to prevent leakage. After rolling and securing the capacitor with zip ties you’ll be ready for the 3nF worth of fun seen in the video after the break. [Grenadier] mentions that this can be improved further if you were to vacuum impregnate the device with beeswax.

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Jeri Ellsworth’s Shooting Gallery

May 9, 2011 by Caleb Kraft 8 Comments

Back with another interesting vidoe, [Jeri Ellsworth] once again brings us an amusing and educational hack. This time she’s made a “shooting gallery” in the style of the old arcade games that actually used projectiles. In her version however, she’s using LEDs in the targets which are detected by the gun. In an effort to keep the feel the same, she rigged up a pinball bell to ding at the appropriate times and it is quite effective.

As usual, she does a great job of breaking everything down and explaining how it all works. She shows us around her prototype so you can see how it is constructed, if you can make it through the solder gun shootout in the beginning. If she were to continue with this project beyond the functional prototype stage, we’d love to see small video clips being displayed for the targets pepper’s ghost style. Maybe we’re just having fond memories of Time Traveler.

Roll Your Own Capacitors

May 9, 2011 by Mike Nathan 30 Comments

diy_caps

Rolling your own electronics components can be fun, but can also help in explaining how certain items actually work. [Addie] from The Toymakers recently set off to figure out how capacitors work, by making her own.

She understood the general concept behind capacitors and how they are constructed, but she wanted to see how it was done first-hand. To construct her capacitor, she selected aluminum foil as her conductor, and saran wrap as the dielectric. She admits that her first attempt was a failure, but undaunted, she carried on. Friends suggested that her conductors were a bit too small to hold any reasonable charge, so she tried larger sheets of aluminum foil to no avail.

She kept at it and found success after using several feet of foil to construct her capacitor. She charged it with a handful of AA batteries and was excited to see her multimeter come to life when she touched the leads to the cap.

While you likely wouldn’t use a hand-made capacitor in your next build, it is a fun experiment to do with children interested in learning about electronics.

[via Adafruit blog]

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Digital Picture Frame Reverse Engineering

May 7, 2011 by Mike Nathan 22 Comments

coby_frame_hack

A few months ago [Jason] got his hands on a free Coby DP700WD digital picture frame and thought it would be fun to hack. After realizing that the frame did not run any sort of Linux-based OS he figured his options were pretty limited, but he gave it a shot anyways.

The frame came with a set of built in images, and his goal was to swap them out for pictures of his own. He started by trying to read data from the frame’s serial flash chip, but found that the processor was preventing him from doing so. He de-soldered the chip from the frame, mounted it on a makeshift breakout board, and started reading up on SPI.

He was eventually able to read the device’s flash chip and swapped out the built-in images with his own. After a bit of trial and error, he was able to replace the frame’s boot screen with his own custom image as well.

If you are looking to do something similar, be sure to swing by his site – all of the tools and code he used to hack his frame are available for the taking.

Continue reading to see his modified picture frame in action.

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Mini Light Table Fits Inside A Briefcase

May 5, 2011 by Mike Nathan 38 Comments

portable_light_box

Hackaday forum member [Mike] was looking for project ideas when his girlfriend, an art major, suggested that he build her a light table to help with her various assignments. Having seen a few of these projects pop up from time to time, he figured he was up to the task. He started hunting around at his local thrift stores and finally came across what he was looking for – a hard-sided Samsonite briefcase.

He ripped out the bottom lining of the briefcase and proceeded to paint the inside white in order to properly reflect the lighting he would be adding shortly. A pair of under-cabinet lights were installed, and wired to be easily toggled on the outside of the case. He located some white acrylic to serve as the top of the table, trimming it to fit snugly in the case without any need for fasteners.

His girlfriend loved the table, though we would be interested in seeing a more portable version – it is built into a briefcase after all. We would love to hear your suggestions on how he might make this more portable, so let us know in the comments.

Meet Mr. Clappidoo

May 4, 2011 by Mike Nathan 12 Comments

mr_clappidoo

[Laurence] tinkers around the house quite a bit, making all sorts of fun interactive toys for his children to play with. Mr. Clappidoo is a toy that he finished a while back, which bears a striking resemblance to one of his projects we recently showed you, Papydoo. This is not a coincidence, as Papydoo was created after Mr. Clappidoo was built, borrowing many features from his predecessor.

Who is your daddy and what does he do?

It’s a good thing you asked. Mr. Clappidoo uses an IR motion sensor to detect nearby objects, waking up and interacting with whatever crosses his path. He is capable of four different random moods ranging from angry to flirty. He projects these moods by changing the color of his LED-lit eyes as well as playing simple sounds. A balsa wood chest makes up Clappidoo’s body, and he repeatedly claps his ~~lid~~ mouth open and shut using a small servo, hence the name.

Like his other projects, [Lawrence] has focused his efforts to ensure that the three AA batteries used to power Clappidoo last as long as possible. He says that with moderate usage the device can run off the same set of batteries for a few months before needing replacement.

It’s a fun little contraption, sure to please the kids. Stick around for a quick video of Clappidoo in action.

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Old Computer Parts Demonstrate How Particle Accelerators Work

May 3, 2011 by Jesse Congdon 12 Comments

[Ameres Valentin] writes in to let us know about his DIY particle accelerator model. The model, made mostly out of old computer stuff, mimics a linear high-energy particle accelerator which use drift tubes to toss particles around. Drift tubes work by first attracting a particle (in this case, ball bearing) until it crosses a charged plate (in this case, coil), then flipping the charge polarity and repelling the particle. In this case the accelerators function more like a multiple coil gun, as they can’t exactly push the bearing away. Regardless of the specifics the model is an excellent visual aid.

As the bearing rolls along the rails of the CD spindle it shorts bits of foil tape placed just ahead of the magnets. This (appears) to flip a relay that switches on the magnet. Once the magnet coil is energized it pulls the bearing towards its center, accelerating it. The foil stops just before the point where the magnet would pull back the bearing. We are not sure if [Ameres] is using any trickery to get the magnets to individually power, as schematics are not available. The circuit should be simple enough to figure out with a couple relays. In the video [Ameres] adds a lamp to the coils to display when they are powered. Nice work! This could make a fun ~~distraction~~ desk accessory, better than those clicky Newton’s cradles.

Check out [Ameres]’ site for a video of the model in action.