Bench Power Supply Resetting Thingy

June 25, 2012 by Jake W 14 Comments

As is common among some hackers, [Henry] re-purposed an ATX power supply unit to function as a bench power supply for testing circuits on a breadboard (much like this fancy example).

However, safety mechanisms on some modern PC PSUs do not automatically reset after over-current protection has kicked in, which soon became annoying for [Henry]. In order to make his power supply more hacker-friendly, he wired up and programmed an ATtiny85V, using some Arduino libraries, to do that for him. This simple project is a great example of using a hack to improve a pre-existing hack.

Hackday Links: March 16, 2012

March 16, 2012 by Mike Szczys 6 Comments

Shamrock hat

[Josh] whipped up a shamrock themed hat by adding an outline of green LEDs to this bowler. Just remember, don’t drink and solder. Happy St. Patrick’s Day everyone!

Battery-powered Xmas lights can be more useful

[Karl] took a string of mostly useless battery-powered Christmas lights and found a good use for them. He replaced the stock board with a boost convert and uses the two AA batteries as a 5V power supply when mains power isn’t handy.

3D printed appliance repair

The broken plastic piece seen here keeps a dishwasher closed while running. The part couldn’t be sourced by a repairman but the best solution turned out to be printing a perfect replacement part.

Generating labels for resistor storage

[Darrell] picked up a surplus test-tube rack to use as resistor storage. It’s a great system, but his Ruby script that uses LaTeX to generate color-coded labels is a really nice touch as well.

DeLorean quadcopter build log

No, it’s not a dupe. [Alp_X] found the link to a build log for the DeLorean quadcopter that headlined our last Links post. It’s in Russian but the machine translation should help a bit.

Squeezing The Juice Out Of Some AA Batteries

February 27, 2012 by Mike Szczys 75 Comments

[Ray’s] breadboard power supply lets you drain the last traces of power from ‘dead’ AA batteries. Electronics that are powered off of disposable alkaline batteries have a cutoff voltage that usually leaves a fair amount of potential within. Since many municipal recycling programs don’t take the disposables (you’re just supposed to throw them in the trash!) we love the idea of squeezing them for prototyping use.

His design uses just one IC, the MCP1640, along with a handful of passive components. The chip is a boost converter with a startup voltage of just 0.65V, which means the batteries themselves – normally starting life above 1.5V – can be used until they drop to about 0.3V each.

Above you can see the kit he is selling. But it’s an open source project and the circuit is so simple we’re sure you can build your own. Add that boost converter chip to your next parts order for around $0.40.

[Ray] made a nice demo video for the device which you can see embedded after the break.

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Cockroft-Walton Multiplier Can Output Positive Or Negative Voltage

February 10, 2012 by Mike Szczys 16 Comments

If you’ve already dipped your toes into high-voltage power supply pool you may be thirsty for a bit more knowledge. Here’s a neat illustration of how to build a voltage multiplier that can output a positive or negative supply. It is based on a design known as the Cockroft-Walton Multiplier. It’s the add-on housed in the plastic box seen in the image above. It uses diodes and capacitors in an orientation very common for generating high voltages. In fact, the same thing can be found in that high-voltage bulletin board. The place this differs is when it comes to connecting the multiplier to the PSU.

If you look closely you can see one red and one black banana plug jack poking out the end of the plastic container. There is also a pair of these on the other end. The multiplier has been designed so that reconfiguring the inputs and outputs changes how it works. Each jack has been labeled with one possible input and one output. Choose the desired output (DC+ or DC-) and then follow the labels for the rest of the connections.

What can you do with this setup? Check out the clip after the break that shows it powering a lifter.

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The Ultimate Breadboard – A Prototyping Station That Has It All

February 9, 2012 by Mike Nathan 27 Comments

[Claudio] was working on a homebrew oscilloscope project when he started thinking about how unsuitable a standard breadboard is for a large-scale project. Rather than adding components on top of components until they became what he lovingly calls a “fragile, unforgiving crapstack”, he decided to build himself the Ultimate Breadboard.

He packed so much into his design, that it’s honestly hard to know where to begin describing it. Aside from an appropriately large breadboarding surface embedded in the center of the console, he added a power supply to the left hand side, which sits just below an Avr-Net-IO board. The right side of the console features an Arduino NG, and a pair of level converters. He also added some LED-based VU meters, a couple of 7-segment displays, an LCD display, an analog voltmeter, along with plenty of I/O connectors.

The Ultimate Breadboard might look a bit daunting at first, but it seems like an awesome setup on which to do any sort of prototyping. Be sure to check out the video below for more details and to see [Claudio] give a tour of the device.

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Replacing An Overheating Tablet Power Supply

January 13, 2012 by Mike Szczys 28 Comments

[Dave] has an ASUS tablet PC with a little problem. The device is charged via the docking connector’s USB cable when plugged into a special wall transformer. The problem is that the wall unit tends to overheat, and is shut down by a thermister inside to avoid permanent damage. The word on the Internet is to drop it in a zipper bag and chill it in the freezer for a bit. Although this works, it’s not the permanent solution that he was looking for. Instead, he hit the parts bin and built his own power supply replacement without buying anything.

The device is simply looking for 12V on the power pin (pin 1) of the USB cable. [Dave] dug through his mountain of unused AC adapters and found one that fit the voltage and current specs of the stock unit. He also grabbed a dusty old motherboard and plucked the USB ports off of the back. A bit of protoboard makes for a good base to connect the AC adapter wires to the ports, which was then covered with one big shrink tube. The result is seen above, and demonstrated in the clip after the break.

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Exposing Some Fake Electronics With Too-good-to-be-true Prices

January 4, 2012 by Mike Szczys 130 Comments

[Giorgos Lazaridis] needed an AC adaptor for his Canon PowerShot camera. He hit eBay and was excited to find this branded adaptor for just five bucks! It works and, even though it would sometimes reboot his camera if the cord was twisted around in the jack, he was satisfied that it did what it was supposed to.

That is, until one day he observed some very peculiar behavior while taking pictures of a PIC circuit he was prototyping. When holding the camera and putting his other hand near the breadboard one of the status LEDs in his circuit began flashing sporadically. If he was using the camera with batteries instead of the adapter this didn’t happen.

His first instinct was to hook up the adapter to his oscilloscope and see what is happening on the power bus. The signal is incredibly noisy. Shockingly so. [Giorgos] cracked open the case to see what is going on with the power supply circuit inside. You simply must view the video after the break to see the horror-show he found. The board is poorly soldered, components are not properly seated in their footprints, and our favorite is when [Giorgos] points out a squiggly trace which takes the place of the smoothing inductors.

Have you documented your own fake electronic hardware finds? We’d love to hear about them. Continue reading “Exposing Some Fake Electronics With Too-good-to-be-true Prices” →