LED case lights reflect CPU usage

A lot of Linux users include system monitor information in their status panel so that they can see when the CPU is grinding away. [Kevin] is taking the concept one step further by changing his case lights based on CPU usage. Above you can see green, orange, and magenta, but [Kevin’s] implementation uses the full spectrum of color.

The project is based on an ATmega48. It’s running the V-USB stack and connects to one of the motherboard’s internal USB ports. This lets him easily push the CPU usage data over to the microcontroller where it is translated into color. One RGB LED has been installed behind each fan panel on the front of the case, with a white LED above and below as an accent. Pulse-width modulation via some MOSFETs lets him mix and match for just the right color. He’s powering the add-on off of the PSU rails rather than USB so that it turns off when the computer goes to standby.

Don’t miss [Kevin’s] explanation of the system, and a demo of it in action after the break.

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Chicken coop door using threaded rod

There’s no rooster to wake them up, and [Steve] and his wife are fine with that. What they’re not fine with is having to get up early anyway in order to let the chickens out of the coop. Like many small-scale egg farmers they sought out an automatic solution for opening the coup in the morning.

[Steve] had seen a bunch of different automatic coup door hacks kicking around the Internet. But all of the ones he could find used a vertical door and pulleys. His setup has a door that opens horizontally and he realized that he needed to build some kind of linear actuator. What he came up with is a system built with hardware store parts. He’s using a plain old piece of threaded rod along with a coupling nut (they’re usually 3/4″ long or so). The nut is held firmly on the door using a conduit mounting bracket, while the threaded rod is turned by an electric screwdriver mounted to the jamb. Two limiting switches are made up of magnetic sensors often used to ring the door entry bell when you enter a store. An Arduino takes care of scheduling and controlling the motor for opening and closing the door. See for yourself in the high-production-value video after the break.

For what it’s worth, we have seen at least one rope and pulley door that slides horizontally.

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Drop everything and build this go-kart right now!

There are awesome projects, and then there are things that make us drool on the keyboard. We just got done wiping up our mess after seeing this go-kart which uses four hub-motors as direct drive wheels. We’ll admit, this is more artwork than a hack as these guys are mechanical engineers and know what they’re doing. But how could we pass up sharing something like this?

The design is smaller than any of the other go-karts we remember seeing. The low-backed pilot seat is the biggest part, with a cubby-hole beneath it for the batteries and control hardware. Each of the hub-motors was hand wound and reading through the related blog posts it seems this was a huge and painful part of the build.

So it’s pretty fun to watch these guys tear up the hallways of one of the engineering buildings at MIT. But the footage of a two-kart race up a spiraling parking garage in the middle of the night is absolutely delightful. You’ll find both videos embedded after the break.

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Keyboard composes its own music

Summer is right around the corner and all the final projects from electronic design classes are rolling into the tip line. This time, we’ve got [Chaorong] and [Siyu]’s auto-composing keyboard from their time in ECE4760 at Cornell.

The keyboard has two modes: a ‘happy’ mode and a ‘tender’ mode, the difference being the tender mode is slower and sounds a little like a lullaby. After two keys are pressed, the ATMega644 figures out what key it should play in and starts generating a random-ish sounding song using a Markov probability matrix.

There’s a third option for the keyboard as well: play a short melody and the software will loop through a few permutations of the melody. After the break, you can see [Siyu] play Ode to Joy and have the autocomposer improvise around the tune. Very, very nice work and we can’t wait to see more senior design projects hit the tip line.

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RCA Capacitive Electronic Disk

capacitive video disk

Although not a hack in the sense that it was made by a large corporation, check out this capacitive electronic disk that [danielbpm] wrote in about. Here’s a Wikipedia article about it, as well as a video (which didn’t embed correctly) about how it was made. The disks look like a typical audio record, and it was conceived of in 1964. A prototype was manufactured in 1972.

Unlike the more well-known Laserdisk format, the [Capacitive Electronic disk], or [CED] used an actual stylus to read the disks. Because of this, the [Wikipedia] article astutely points out that both systems were mutually incompatible. Somewhere there might have been a scratched Laserdisk next to the VCR with a sandwich stuffed in it. The computer with a broken coffee holder wouldn’t come for another few years.

Although it may have been a good format in it’s own right, like Betamax or HD-DVD, this system wasn’t destined to become the Blu-Ray player of it’s time.

Tindie: an etsy for electronics

If you have a finished project you’re now bored with, here’s Tindie. It’s a one-man operation headed b [emile] that hopes to connect makers with people who think DIY projects are really cool and have money.

There are already a few websites that cater to the builder who wants to sell projects: Kickstarter for one, but this is based on the concept of campaigns. Tindie aims to be a techie etsy, according to [emile]’s market research post on reddit;  a places for makers with a soldering iron to sell stuff, but who are baffled by the concept of knitting.

Right now there’s nothing to buy on Tindie – [emile] is looking for hackers to sell their projects so the store doesn’t launch with an empty stockroom. If you’ve got an old project sitting on your shelf that you’d like to sell, put it up. [emile] is only taking 5% of the sales – just enough to pay for the hosting. Hopefully it will be popular enough for the eventual Tindie/regretsy blog.