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Put that headphone jack anywhere you want it

yamaha-keyboard-headphone-jack-hack

Check out this brand new Yamaha keyboard. The fact that we’re seeing the guts means that [Todd Harrison] can kiss his warranty goodbye. But by now you should know that he doesn’t look to others when something goes wrong with his electronics. This time around he’s not repairing anything. He didn’t like having to plug in headphones on the rear of the keyboard. He cracked it open and relocated the headphone jack to a more convenient location.

As you can see, there’s a ton of room inside once the MDF base which holds the speakers and some sounding boxes has been removed. While he’s in there he takes a good look at the mechanics of the keys. They’re weighted with metal rods (seen above) to help the electronic instrument feel more like an acoustic version to the player. But he doesn’t neglect the chance to gawk at all the electronics as well.

After pulling out the PCB that has the headphone jack on it he goes to work with a solder sucker. With the solder gone he cuts through the glue that holds the jack on the board. All that’s left is to solder some wire in its place and give it a nice project box as an enclosure. To complete the hack he mounts the box on the MDF base and now the headphones connect on the front. See the entire process in the video after the break.

[Read more...]

Router jig for a perfect circle

router-jig-for-cutting-circles

We once enlisted a contractor to cut a plywood circle for a cat condo we were building. Now we’re embarrassed that we couldn’t come up with a solution as eloquent and easy to use as this circle cutting router jig which [Grays42] built.

He’s using a small trim router for the job. The jig is made up of two thick-walled pieces of PVC pipe. We don’t think the router is attached to jig. Instead you hold it against the wooden spacer which is on the outside edge of the cut. He doesn’t mention how he made the spacers, but we’d recommend cutting a hole the size of the pipes and then ripping down the middle to remove some of the material (tape the two spacers together during fabrication to ensure proper alignment). It just takes some nuts and bolts from the hardware store to assemble everything.

[Grays42] is using this to cut rings for his telescope build. We have our eye on it for making our own wooden Bulbdial clock.

[via Reddit]

Portable audio rig that turned out great

portable-audio-rig

[Michael] wanted a stereo that he could use outside, be it at the beach, beside the pool, or while tailgating. He decided to build this boom box himself, and didn’t cut any corners when it came to a professional looking finish.

Because of the locale in which he plans to use the stereo he went with a set of marine speakers. They’ll have no problem standing up to water, and since they’re used in boats they should also be able to take a beating during transport. To feed it he uses a Lepai T amp which is seen above.

After cutting each piece of the case out of MDF he started working on the openings to receive the components. This involved quite a number of layout lines and some work with a compass to map out the circular openings. He built a recessed panel on the back to interface the power cord for charging. Inside is an 18 Ah battery. A set of switches lets him turn on the charger and choose between powering the amp from battery or from the power cord.

[via Reddit]

UPDATE: Roll your own GPS can now track twice as many satellites

diy-gps-module

[Andrew Holme] wrote in to tell us about some work he’s done to improve his scratch-built GPS receiver. He figured out a way to use the same hardware but double the number of satellites it can track to a total of eight. When we looked at the original hardware about a year ago it was limited to monitoring just four satellites. That’s the bare minimum for calculating position data. This will not only help increase the accuracy, but remove the problems that would have been cause if just one satellite was dropped because of an obstruction or other issue.

His solution is based entirely on using the FPGA in a different way. He had taken up almost all of the gates available in the Xilinx Spartan 3 chip. Now he’s implemented a CPU on the chip and is able take some of the work off of the hardware gate design by running code on it. He also found and squashed a bug in how the data was processed. He says his original work wasn’t taking into account the rotation of the earth when determining position. All of these improvements put his accuracy at +/- five meters even when he’s not tracking all eight satellites!

How to write your own Minesweeper solver

minesweeper-solver

We think we have found project that will take over our holiday free time. [Bai Li] just published an excellent article about writing a program that can automatically solve the game of Minesweeper. For those of you who are unfamiliar, Minesweeper gives you a grid in which land mines have been randomly placed. As you click on boxes to reveal what is underneath you are greeted with a number which represents how many mines surround that box. [Bai's] project examines how the puzzle may be solved programmatically.

He chose to use Java to write the solver. This works well both reading from the screen as well as simulating mouse clicks on the game. The reading portion of the program uses color detection with a screenshot. There were two problems associated with this, the numeral one is almost the same color as an uncovered square, and the numerals seven and three use identical colors. The input portion was much simpler as he’s able to use the existing Robot class.

The logic behind writing an efficient solver is very interesting. One of the most fascinating examples is shown above. What should you do when there is no possible way to ensure a safe move? As with traditional chess games, [Bai] has the solver calculate all possible solutions and choose the move that has the best odds of success.

His source code is available, but won’t this one be fun to hack out from the concepts alone? For some reason this seems more accessible to us than something like the Bejeweled Blitz solver.

[Read more...]

Robot can barely move with so much hardware strapped to it

web-server-robot

We think that [Andrej Škraba] needs to start looking for a beefier motor platform. This little robot has so much hardware strapped to it the motors can barely keep up. But with a little help it can make its way around the house, and it takes a whole lot of connectivity and computing power along for the ride.

The white stick on the top is a single-board computer. The MK802 Mini sports an A10 processor and up to a gig of ram. Just below that is a USB hub which is sitting on top of a USB battery pack. This powers the computer and gives him the ability to plug in more than one USB device. The robot chassis is from Pololu. It uses an Arduino and a motor shield for locomotion, with commands pushed to it via USB.

This setup makes programming very easy. Here [Andrej] has a keyboard and HDMI monitor plugged in to do a little work. When not coding it can be disconnected and driven over the network. He makes this happen using an Apache server on the MK802 and node.js. See a demo of the system in the clip after the break.

[Read more...]

A concrete table with a little blinky built in

concrete-table-with-led-inlay

Members of the Warp Zone hackerspace wanted a coffee table that was beyond ordinary. They ended up pouring a concrete base for the glass top (translated). There were several things to address during the design. First off, they wanted to integrate LEDs in the concrete sides. Some consideration had to be made for portability as concrete is very heavy. The final piece of the puzzle was deciding what kind of hardware to place beneath the frosted glass.

The legs were designed with a large cut-out area to keep them as light weight as possible. The cross piece has a set of voids spelling out the name of the hackerspace with some green LEDs. This was accomplished by placing foam cut-outs of each letter in the forms before for concrete was poured. They sealed around each letter with silicone, but still had some seepage most likely caused when jostling the form to help remove air bubbles. Straws were placed in the foam to allow a cable pass through for the electronics. After everything was in place they filled the voids with hot glue to act as a diffuser.

There aren’t a lot of details about the RGB LEDs under the frosted glass. But you can see the light show they produce in the clip after the break.

[Read more...]

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