Building a DIY GPS cube

Originally, [Karman] wanted to build a speedometer for his bike. Feature creep makes fools of us all, so after a month of work [Karman] had a  GPS-enabled cube that tells him his current latitude and longitude, current time, course, direction and speed.

[Karman]‘s GPS cube uses a cheap GPS module, Arduino Mini Pro, a magnificent OLED display, and a LiPo battery salvaged from a first gen iPod nano. Surprisingly, the build is very clean – there are no wires, headers, or random epoxy globs sticking out everywhere. The entire build is just a bit larger than one cubic inch, allowing [Karman] to carry around the power of a GPS device in his pocket.

The code for [Karman]‘s GPS cube uses the TinyGPS library for Arduino, that has a few great functions that track the number of satellites visible and report the current time. Now all that’s left to do is fabricate a case for this awesome little project. As always, video demo after the break.

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Electronic bike derailleur

[Nabil] sent in an awesome electronic bicycle derailleur. Now, instead of pulling a steel cable with a shifting mechanism, [Nabil] can change gears electronically. As a bonus, the derailleur can be controlled by a small bicycle computer, so he’s always in the right gear.

The new electronic derailleur is controlled by a pair of servos with push buttons in the handle bar. This allows [Nabil] to automatically trim his chain, completely eliminating chain rub.

This electronic shifter is part of [Nabil]‘s much large bike computer project. In addition to electronic control of what gear the bike is in, [Nabil] will be adding a GPS, accelerometer, an altimeter and a heart rate monitor and pulse ox meter. That’s an impressive bit of kit, and we cant wait to see the entire project finished. You can pick up the current version of the design over on GitHub and follow all the updates on [Nabil]‘s blog.

Outdoor stereo helps your neighbors learn to issue noise complaints

Backyard parties are going to rock over at [Effin_dead_again's] house. That’s because he just finished building this outdoor stereo. It carries its own power supply so you can take it on the road with you, and we don’t think you’ll have trouble hearing it with the 240 Watt amplifier hidden inside.

He shared the equipment details in his Reddit conversation. A 12V lawn mower battery sits in the base of the wooden enclosure. One of the commenters mentioned the dangers of hydrogen off-gassing from that power source, but [Effin_dead_again] thought of that and included venting around the lid. The subwoofer is an 8″ Alpine, and speakers are out of a Hyundai car. The head unit has Bluetooth built in for easy connection to your smart phone. It of course has the ability to play CDs and MP3s too, and we’d bet you can tune the radio if there’s an antenna connected.

Need similar power but a bit more portability? Check out this stereo built into a cooler.

Arduino rover doubles up on obstacle avoidance

[Eduard Ros] wrote in show off his first attempt at building an autonomous rover (translated). As with many of these projects, he started with the base of a remote control toy truck. This solves so many mechanical issues, like steering, locomotion, and power source.

He just needed a way to control the vehicle. The recent LayerOne badge hacks either did this through the wireless controller protocol or by adding an Arduino directly to the vehicle. [Eduard] chose the latter, and also included obstacle avoidance sensors in the process. We’ve seen quite a few that use these ultrasonic rangefinders. He decided to go a different route by adding two of them rather than scanning by mounting one on a servo motor.

The video after the break shows the vehicle successfully navigating through a tight space. This makes us wonder how much data can be processed from the stationary sensors? We’re not familiar with how wide the horizontal sensitivity is on the devices. If you have some insight, please share you knowledge in the comments section.

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