Custom Flat Cables To Suit Your Needs

October 26, 2011 by Mike Szczys 17 Comments

[Cosimo Orlando] has a Motorola Xoom tablet. It’s an Android device that works great as a tablet, but can double as a Laptop when you need it to by adding a keyboard. The problem he was having is that the USB On-The-Go cables that he tried were never the right size or orientation. So he scavenged them for parts and built his own flat cable for a custom fit.

The final product pictured here actually uses protoboard to give the body some strength. [Cosimo] first laid out the dimensions on the substrate using a felt-tipped pen. He then took connectors from his mis-sized commercial cables and affixed them to the board with a combination of hot glue and solder. From there, just connect the five data lines and ground with some jumper wire and test for continuity. He finished this off with what he calls ‘adhesive plastic glossy black’ shaped to make a decent looking case. If you have any idea what product was used here, let us know by leaving a comment.

Hacking In Cameroon For Profit And Entertainment

October 22, 2011 by Mike Szczys 24 Comments

[Bill Zimmerman] is in Cameroon and has been posting some really interesting articles about life in the central African nation. It comes as no surprise that imported goods can be prohibitively expensive for many of the country’s residents, so building tools and goods is way to improve life and save money. The image above is a metalworking cooperative where any number of products are manufactured from recycled materials, often using tools that the craftsmen made themselves. Their wares are amazingly wide-ranging; crow bars, motorcycle seats, buckets, plows, hammers, knives, cold chisels, and much more. The video after the break shows the tradesmen hard at work. See some video of the cooperative after the break.

But adults aren’t the only ones getting in on the action. Remember [William Kamkwamba] who built a wind generator for his villiage? It seems the tinkering spirit runs deep in the children of Cameroon as well. [Bill] came across some kids who grabbed leftovers like the soles of sandals, scraps of rope, and empty sardine tins to build a steerable toy car.

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Light Bulb, Diode, And Capacitor Step Mains Down To 12V DC

October 21, 2011 by Mike Szczys 64 Comments

[Todd Harrison] needed a way to run a 12 volt PC fan from mains voltage. Well, we think he really just needed something to keep him occupied on a Sunday, but that’s beside the point. He shows us how he did this in a non-traditional way by using the resistive load of an incandescent light bulb, a diode, and a capacitor to convert voltage to what he needed. You can read his article, or settle in for the thirty-five minute video after the break where he explains his circuit.

The concept here is fairly simple. The diode acts as a half-wave rectifier by preventing the negative trough of the alternating current from passing into his circuit. The positive peaks of the electricity travel through the light bulb, which knocks down the voltage to a usable level. Finally, the capacitor fills the gaps where the negative current of the AC used to be, providing direct current to the fan. It’s easy to follow but the we needed some help with the math for calculating the correct lightbulb to use to get our desired output current.

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Illogical Voltage Double Uses Logic

October 21, 2011 by Mike Szczys 5 Comments

[Jonathan Thomson] just finished writing up his entry for the 7400 logic contest. It’s a voltage doubler that uses a 74HC14 logic chip. Because this is not at all what the chip was meant for–and he’s a sucker for puns–he’s calling it the Illogical Dickson Doubler.

What he’s got here is basically a charge pump built from a set of diodes and capacitors. On the breadboard you see two chips, one is used as a clock signal generator for the other which is acting as part of the charge pump. We’ve seen a string of hacks that ~~mis~~use the protection diodes on the inputs of logic chips. In fact, [Jonathan’s] setup uses the same back power concept that barebones PIC RFID tag did. You may remember in that project the chip was being powered from one of the I/O pins, with the VCC pin not connected to anything.

We’ve embedded a video after the break with shows some voltage measurements, as well as an LED being powered from the doubling circuit.

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RAM Upgrade For WRT300N Router

October 20, 2011 by Mike Szczys 1 Comment

[Heli] had a WRT300N wireless router sitting around collecting dust. He decided to squeeze at bit more entertainment value out of it by seeing if he could pull off a RAM upgrade. He managed to double the router’s RAM and posted a walk through (translated) to help you do the same.

Swapping out surface mount RAM chips isn’t the easiest thing in the world and you must wondering what prompted this. It seems he wanted to run the LuCI package on the router but it was slow (or even incapable) of booting with the stock hardware’s 16 Mb. He first sourced some pin-compatible replacement chips from an old Pentium III computer. While his soldering iron was hot, he also wired up a JTAG header, which connects via the red wires just visible to the left. When he first fired up the unit he was happy that it was able to boot, but it still only detected 16 Mb.

It turns out you’re going to need to roll your own kernel to get it to take advantage of the upgrade. Source code for OpenWRT is easy to find and there’s plenty of guides for compiling it. If you try this, make sure to read [Heli’s] post carefully as he’s got some important configuration information that will help you to avoid bricking your router.

Analog Test Interface For Your Computer

October 20, 2011 by Mike Szczys 6 Comments

Wanting to test the response curves on some analog parts, [Don Sauer] devised a way of using simple tools to graph analog tests on a computer. Here you can see the results of testing NPN, PNP, NMOS and PMOS transistors, but modifying the input circuitry would let you test just about anything you want.

[Don] is using an Arduino as the hardware interface. He needed some additional parts, like an op-amp and some passives. Instead of building this on a breadboard, he printed the circuit out on a piece of cardboard, hot glued the components in place, then wired them up. This will let him reuse the interface in the future, but is quicker than designing and etching a PCB.

He uses a Processing sketch to capture the test data streaming in from the Arduino. Once recorded, he uses SciLab to create the graphs. He also covers a method of sifting through the data using Octave, another open source program that feels somewhat like MATLAB.

A CD Changer Made Of Wood

October 18, 2011 by Jeremy Cook 15 Comments

Although this is by no means a new hack – it was made circe 2002 – this wooden CD changer is an interesting piece of machinery. The whole thing is a simple pick-and-place device. The gripper is brilliant in it’s simplicity, using only a rubber band, wood, and a solenoid. It grips the CD by the middle hole, picks it up, and the assembly then travels to the CD tray or the stack. Everything works with DC motors and string, and several micro-switches make sure everything is picked up and dropped in the correct position.

Although we may think this is a pretty cool device, [Matthias] is quite humble about his machine’s abilities. In his estimation, although one could probably duplicate 12 CDs with relative ease, if you really wanted to duplicate a large number, it’d be best to buy one. Maybe he works in manufacturing.

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