Using GPS to stay aware of red light cameras

red-light-camera-alerter

Depending on how you view them, red light cameras are a great way to get people to drive carefully, or an utter nuisance. We agree with the latter opinion, as does [Dave], so he built a handy little device that alerts him when he’s about to approach one of these intersections.

His Red Light Camera Alerter is based around an Atmega 328P sporting the Arduino bootloader. The micro obtains GPS coordinates while [Dave] is driving, comparing his current location with a table of all known red light intersections in the area. As he nears a red light camera, the status LED changes colors from blue to yellow to red as he gets closer, making it easy to keep aware of his situation. He also included an Adafruit OLED display in his device, which relays his speed, GPS coordinates, heading, and actual distance from the red light in real time.

While [Dave] admits that he doesn’t really have a need for the alerter as there are only a couple located in his immediate vicinity, he says it was a fun and easy way to get some experience with using GPS sensors in his projects. He doesn’t have any video of it in action, but you can find the code he uses to drive the alerter on his blog.

Simple tweak alerts you when you've left your headlights on

landrover-headlight-buzzer

[Paul McGuinness] owns a Series III Land Rover, and as the vehicle as formerly used by the British military, it’s lacking some of the modern amenities he was accustomed to. Overlooking the lack of power steering and all-around drum brakes, the one item that [Paul] really missed was a buzzer that let him know when he left the lights running.

On more than one occasion, he’s had to have “The Sarge” jump started after leaving the lights running all day. Explaining the humiliation involved with jump-starting a Land Rover with a Nissan Micra (an unfortunate excuse for a vehicle, known here in the states as the Nissan Versa) in his blog, [Paul] decided that he’d had enough – it was time to build a headlight warning buzzer.

The circuit itself is straightforward, consisting of a normally closed relay connected to his headlights and ignition, along with a buzzer. When the key is in the ignition and the lights are on, the relay is open and the buzzer is silent. However, if the lights are on and the relay is not supplied power from the ignition, it closes and sounds the alarm.

A simple fix for a frustrating problem – we like that.

Digital speedometer with an arduino

[Martyn] is restoring a 32-year-old Honda motorcycle, so when the ancient speedometer broke last year he thought it was prime time to start of a digital speedometer project. We’re loving the results so far, and would love seeing it on a nicely restored bike.

Instead of the relative horror of driving 40 LEDs with a single Arduino, [Martyn] bit the bullet and got a Maxim 7221 LED driver. Controlling 64 LEDs  over a three-wire interface simplified the board design somewhat, allowing [Martyn] to etch his own PCB with the toner transfer & HCl/H2O2 method. To actually power and control the entire circuit, [Martyn] used an Arduino loaded up with a program based  LedControl library makes programming the spedometer a snap.

Although the speedo works, [Martyn] says he isn’t proud of how it looks. We don’t mind – the candy colored jumpers add a nice flair to the project, and they’re hidden behind the face plate of the speedometer. We’re sure once he gets the neutral, high-beam, and warning indicators working with the LED bar array / tachometer, everything will look awesome.

via reddit

Riding rockets and jets around the frozen wastes of Sweden

An attentive reader tipped us off to the guys at Mobacken Racing (translation), a group of Swedes dedicated to the art and craft of putting jet and rocket engines on go karts and snowmobiles.

One of the simpler builds is a pulse jet sled. Pulse jets are extremely simple devices – just a few stainless steel tubes welded together and started with a leaf blower. The simplicity of a pulse jet lends itself to running very hot and very loudly; the perfect engine for putting the fear of a Norse god into the hearts of racing opponents.

Pulse jets are a bit too simple for [Johansson], so he dedicates his time towards building a jet turbine engine. Right now it’s only on a test stand, but there’s still an awesome amount of thrust coming out of that thing, as shown in the video after the break.

In our humble opinion, the most interesting build is the 1000 Newton liquid fuel rocket engine. The liquid-cooled engine guzzles NOX and methanol, and bears a striking resemblance to liquid fuel engines we’ve seen before. Sadly, there are no videos of this engine being fired (only pics of it strapped to a go-kart), but sit back and watch a couple other hilariously overpowered engines disturbing a tranquil sylvan winter after the break.

Edit: [Linus Nilsson] wrote in to tell us while the guys at Mobacken Racing are good friends, [Linus], his brother, and third guy (his words) are responsible for the pulse jet sled. The pulse jet is actually ‘valved’ and not as simple as a few stainless steel tubes. The pulse jet isn’t started by a leaf blower, either, but a four kilowatt fan. [Linus]’ crew call themselves Svarthalet racing, and you can check out the Google translation here.

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Robotic assist helps paraplegic stand and move around

Seeing this device help a man get up out of his wheelchair makes us wonder why this hasn’t been around for ages. The design principles behind the Tek RMD greatly benefit those without use of their legs. But it’s not just to help him stand, it also serves as motorized transport that makes bulky electric wheelchairs look so last century.

Instead of having the support structure beneath the rider, the RMD (Robotic Mobilization Device) uses a sling-like method to hang from the hinged arm. A folding handlebar can be raised up, allowing the rider to move from sitting to standing with a bit of help from the machine. Whether upright or sitting, the device can travel using its electric motors. In fact, this tip was sent in because it looks very much like riding a Segway.

The video demonstration after the break really hits home the functionality provided. This is an instant quality of life improvement, breaking down some of the barriers of moving around in confined quarters with a motorized wheelchair. There is also a lot to be said for having the option to stand. The demo shows several circumstances like shopping at the market, going through the checkout, and grilling out. What an amazing use of technology.

[Read more…]

Never miss your transport with this bus arrival notifier

[John Graham-Cumming] was all set to start a new project based on the Raspberry Pi. Well, that was until shipment was delayed due to manufacturing issues. Not to fret, he transitioned over to a router board which displays the arrival countdown for mass transit bus service.

He based the build on a web page the Transport for London provided. You can load it up and see if your bus is running on time or not. There’s no published API, but by studying the source code from the site [John] was able to figure out how the JSON commands were formatted.

The next step is building a standalone device to pull the data and display it. The board seen above is from a Linksys WRT54GL router. This longtime favorite has a serial port header which can be driven from the Linux kernel. He wired up a jack on the router’s case, and uses an extension cable to get from it to the 7-segment displays mounted in a model of the bus. Since there’s four digits the display can tell you minutes until the arrival of two different buses.

[Thanks Pseudo Lobster]