Peer network using graphing calculators

These calculators are networked together, able to pass information and play games on a multi-screen playing field. All of this is thanks to [Christopher Mitchell's] work on a package called CalcNet. This networking software takes advantage of [Christopher's] shell and GUI for TI calculators called Doors CS. To demonstrate the high reliability and throughput of his network he wrote NetPong, a multi-calculator version of the popular game that you can watch in a clip after the break.
This is definitely an instance where asking ‘why?’ is the wrong question. We’re more interested in the how, a question you can answer for yourself by reading the whitepapers he provided in both of the links above. [Christopher] knows what he’s doing, he proved that with his face-recognizing augmented reality.

ATX psu turned into an adjustable voltage bench supply

Here’s a fancy way to convert an ATX powers supply into a bench supply. [TG] didn’t just cut off the motherboard connector and add banana plugs, but improved the functionality. Right off the bat you’ll notice that he’s added a control panel. There is an Ammeter and Ohmmeter to let you know what the unit is putting out. He added an MIC29152WT adjustable voltage regulator so that he’s not limited to the fixed voltages of the psu. As a final touch he added an external voltage probe which can be used with the flick of a switch. It’s no replacement for a proper bench supply, especially since it doesn’t have adjustable current limiting, but it’s a nice improvement upon previous psu hacks.

Lego machine predicts future eclipses

Hidden behind the white face plates of this machine are racks of gears that make up a replica of one of the oldest known mechanical computers. This is a working model of the Antikythera mechanism made from Lego pieces. In the video, which you absolutely can’t miss after the break, The machine is disassembled into its various components. Each mechanical unit takes advantage of gear ratio combinations to perform numerous levels of mathematical functions in order to display the date and time that future celestial events will occur.
The background information on the original device reads like the script for a sequel to The Goonies. Believed to date back to 100-150 BC, the stone bronze mechanism was recovered from a shipwreck around the turn of the twentieth century. The use of x-ray analysis helped to unlock the functions and confirm the theories of its operation.
Part of what makes this so interesting is the historical connection. But the production quality of the video (which to be fair, seems to be an advertisement) really brings home how complicated this process is. Now it’s time for us to watch the video a few more times, sketching out the gearing to see that this works as they say it does.
Want more of the Antikythera mechanism? Check out the model built by [Tatyana van Vark].

Analog computer does math

This analog computer can multiply, divide, square numbers, and find square roots. It has a maximum result of ten billion with an average precision of 2-3%. [Miroslav's] build recreates something he saw in a Popular Electronics magazine. It uses a resistor network made up of three potentiometers with a digital multimeter is an integral part of the machine. To multiply a number you set the needles on the first two knobs to the numbers on which you are operating. To find the result turn the third knob until the multimeter has been zeroed out and read the value that knob is pointing to. It seems much more simple than some of the discrete logic computers we’ve seen, yet it’s just as interesting.

Etch-a-Sketch computer is a surprisingly simple hack

We’re not sure whether to call this an Etch-a-Sketch upgrade or a computer interface downgrade but either way it’s unique. [Martin Raynsford] added a familiar red frame to his computer monitor with classic white knobs that control horizontal and vertical cursor movement. There’s even the click option by pressing the buttons in and, as you can see after the break, the modifications result in a perfectly usable digital Etch-a-Sketch. We’ve seen a lot of computer controlled versions of the toy which use fancy parts and take quite a bit of skill to build. This mimicry of the functionality is easy to build and the idea is genius in its simplicity. [Martin] separated the encoder wheels from a mouse. He placed each on one of the knobs and ran wires for sensors and micro-switches back to the original PCB which is stuck to the back of the monitor. From the computer’s point of view it looks and acts like a normal mouse but this is so much more fun (and less productive). Read the rest of this entry »