Replacing An Overheating Tablet Power Supply

January 13, 2012 by 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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Tool Box Light Dimmer Helps Out A Friend, Offers Up Design Tips

January 13, 2012 by 12 Comments

toolbox-lighting

[miceuz] has a friend that works as a theatre technician, and in the course of his job he often needs to jigger with various stage components while shows are in progress. As you can imagine, the lighting situation is far from ideal, so he asked [miceuz] to build him an adjustable lighting solution for his tool box.

The circuit itself is relatively straightforward, using an ATMega88 to provide the PWM required for dimming and color control. Input is taken from three different sources, a rotary encoder for color selection, a pot for brightness control, and a button to turn the light strip on and off.

[miceuz] says that while project came together pretty easily, it still presented some issues along the way which provide some useful design reminders for beginners (and some veterans) alike.

First and foremost: debounce, debounce, debounce. [miceuz] forgot this mantra and made a mad dash to add capacitors to his design after etching the PCB to ensure that his inputs were not bouncing all over the place. He also noted that one should always be sure to read the ADCL before the ADCH register when decoding ADC data. His final observation is that using thick traces is the best policy whenever possible – he ran into a lot of issues with traces detaching during assembly, which he had to rework with wire and solder.

In the end, his friend was happy with the result, and [miceuz] is a better hacker for having worked through his issues. What sorts of important/useful lessons have you learned through the course of your projects? Be sure to share them with us in the comments.

[Pythagoras], A Delta Robot For Drawing

January 13, 2012 by 11 Comments

[Pythagoras] is a delta robot built originally using RC servos. Humbly, [Aaron] “concedes” that the first version of his delta robot using hobby servos was easy to build. As anyone who has built any kind of robot knows though, there is definitely a lot of work involved in even the simplest robot. Coordinating three axes and programming it to draw a picture is a really great accomplishment.

The second version, however is currently in development and uses stepper motors instead of servos. These upgraded motors should make the robot faster, more controllable, and more accurate. This version is at least somewhat working as evidenced by the time-lapse video after the break.

Although the title page listed above is a little sparse on build details, if you dig deeper into the page, there are actually 15 articles about the ‘bot, so be sure to poke around. Continue reading “[Pythagoras], A Delta Robot For Drawing” →

Building A LED Strip The Minimal Way

January 13, 2012 by 6 Comments

For his first big build with an MSP430, [Javon] decided to an RGB LED fader. Having worked with Arduinos in the past, he figured that his MSP430 would have a few PWM channels. After being proved wrong by the data sheet, [Javon] needed to figure out a way to switch a bunch of RGB LEDs with only one PWM channel on his microcontroller.

Because there was only one PWM pin on [Javon]’s micro, he needed a way to multiplex his output. He ended up using a 74HC4052 mux/demux chip to drive 20 LEDs. The LEDs were mounted onto hard board and the main part of the circuit built on a bit of perfboard. While there’s no total cost for his build, we’re guessing [Javon] didn’t spend much on his project; certainty much less than this explosion of LEDs.

[Javon] put all the build pictures up as a Google+ album and a few video demos up. Check those out after the break (009 Sound System warning, you might want to hit mute).

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Hackaday Links: January 13

January 13, 2012 by 18 Comments

An 8×8 LED Matrix Game Grows Up:

[Pixel Land] is an iPhone game similar to [Super Mario Brothers] using a virtual array of 8×8 pixels. This wouldn’t normally be interesting, but we’ve actually featured “this” game as an 8×8 LED matrix game.

How to Drill Golf or Ping-Pong Balls:

Drilling golf or ping-pong balls is not easy.  This simple drill press fixture makes that job easier and repeatable. So the next time you want to make lots of diffusers for your LED board, this might be a good device to consider!

The PICkit 2:

If you’ve ever wanted to get into PIC programming, possibly the PICkit 2 would be for you. [Ray] has written a review of his first experiences with setting it up and programming.

Mr Bitey is hungry for resistors!

Is light industrial machinery a hack? It’s a hard thing to define, but if so [Mr. Bitey] would meet the qualifications.  It also meets the qualifications of having a great video, and name, so be sure to check it out!

A [Snap Circuits] Programmable Robot:

The robot pictured above on [Instructables] was built using [Snap Circuits], with parts that literally snap together. A neat concept, this construction set seems to fall somewhere between traditional Legos and push-in breadboards.

An E-paper Information Panel

January 13, 2012 by 19 Comments

With all the Kindles and Nooks we’re bound to find at yard sales and thrift shops in the coming years, this might be useful. [Chris] made a door-mounted e-paper display to keep himself up to date on recent events.

The hardware comes from an e-paper development kit [Chris] and his friend [Deian] were given a few years back. The dev kit sat in a dusty drawer until [Chris] decided to do something with it. With his door looking like a suitable palette, [Chris] decided to make an information panel that displays the date, his calendar, the weather, and a few RSS feeds.

There was already a Gumstix single board computer attached to the e-paper display, so [Chris] wrote a few scripts on his server and upload information to the paper display. The server renders the display as a PNG image at 800×600 resolution, converts it to PGM and compresses it for the Gumstix. There is a script running on the Gumstix to download the image from the server every five minutes and put it up on the display.

With the awesome readability and low power consumption of e-paper, we’re surprised we haven’t seen a project like this before. Guess we’ll have to wait until Kindles start showing up at flea markets.

Automating The Shutdown Of APC UPS Devices

January 12, 2012 by 56 Comments

ups-shutdown-device

[Ishan Karve] works in some bizarro world where the building management demands that all servers and Uninterruptible Power Supplies be shut down at the end of each evening. While inconceivable to most systems admins, he has no recourse but to comply. This means that his employees need to turn things off before they leave for the day, and since they often work up to 15 hours a day, waiting for Windows server to shut down seems like an eternity.

Being the good manager he is, [Ishan] decided to build a device that handles the clean shutdown of their servers and UPS for them. An Arduino board serves as the brains of the device, communicating with and issuing shutdown commands to the UPS over a serial port. The Arduino is also connected to the office network, enabling it to send ARP requests to the servers in order to determine when they have completely shut down for the day. In order to protect against an accidental shutdown due to network connectivity issues, [Ishan] added an RTC module to the mix so that the Arduino does not issue shutdown commands until at least 8 pm.

Instead of waiting around for Windows to do its thing, [Ishan’s] employees can take off once they start the server shutdown process, knowing that they are totally compliant with their landlord’s crazy requests.