[Graham] over at FUBAR labs took it upon himself to build a rocket engine. This isn’t a simple solid-fuel motor, though: [Graham] went all out and built a liquid-fueled engine that is ignited with a spark plug.
The build started off with a very small ‘igniter’ engine meant to shoot sparks into a larger engine. This engine is fueled with ethanol and air – not the best fuel for a rocket engine by a long shot but save and cheap enough to do a few serious experiments with.
To test out this small engine, [Graham] made a test platform out of aluminum extrusion to remotely control the fuel and oxidizer valves. The valves are controlled by an Arduino and XBee for remote operation and a telemetry downlink for measuring the fluid flow into the engine.
After he had some experience with pressure, plumbing, valves, and engines, [Graham] upgraded his fuel and oxidizer to gaseous oxygen and ethanol. With proper safety protocol in place, [Graham] was able to a series of three 3-second burns less than a minute apart as well as a single burn lasting nearly 5 seconds.
Even though [Graham] eschewed the usual stainless steel construction of rocket engines (his engine is milled out of aluminum), he demonstrated it is possible to build a real liquid-fueled rocket engine at home.
The Burrito Bomber, created by the folks at Darwin Aerospace, claims to be “the world’s first Mexican food delivery system.” The delivery process starts with the customer placing an order through the Flask based Burrito Bomber webapp. The customer’s location is grabbed from their smartphone using the HTML5 Geolocation API and used to generate a waypoint file for the drone. Next, the order is placed into a delivery tube, loaded onto the drone, and the waypoint file is uploaded to the drone. Finally, the drone flies to your location and drops the delivery tube. A parachute deploys to safely deliver the tasty payload.
The drone is based on a Skywalker X-8 airframe and the Quantum RTR Bomb System. The bomb system provides the basic mechanism to hold and drop a payload, but Darwin Airspace designed their own 3D printed parts for the delivery tube. These parts are available on Thingiverse. The drone is controlled autonomously by ArduPilot, which uses the webapp’s waypoint output to guide the drone to the target and release the payload.
Unfortunately, this can’t be a commercial product yet due to FAA regulations, but the FAA is required to figure out commercial drone regulations by 2015. Hopefully in 2015 we’ll all be able to order burritos by air.
For all the source and models, check out the group’s Github. There’s also a video of the bomber in action after the break.
Continue reading “The Burrito Bomber”
[Ladyada] and [pt] had an old keyboard from NeXT, but since it used a custom protocol it wasn’t usable with modern hardware. So they built a custom device to convert the NeXT protocol to USB.
The device uses a Arduino Micro to read data from the keyboard and communicate as a HID device over USB. It connects to the keyboard using the original mini-DIN connector, and is housed in the classic Altoids tin enclosure.
Since the protocol used by NeXT isn’t standard, they had to figure it out and write some code to interpret it. The keyboard communicates bidirectionally with the computer, so they needed to send the correct frames to key data back.
Fortunately, they hit on a Japanese keyboard enthusiast’s site, which had protocol specifications. They implemented this protocol on the Micro, and used the Keyboard library to create a HID device.
The final product is an adapter for NeXT to USB, which allows for the old keyboards to be used on any computer with USB. It’s a good way to bring back life to some otherwise unusable antique hardware.
[Steve] needed an alternative to the Xserve, since Apple stopped making it. His solution was to stick 160 Mac Minis into a rack. That’s 640 real cores, or 1280 if you count HyperThreading.
First, Steve had to tackle the shelving. Nobody made a 1U shelf to hold four Minis, so [Steve] worked with a vendor to design his own. Once challenge of this was managing the exaust air of each Mini. Plastic inserts were designed to ensure that exaust wasn’t sucked into the intake of an adjancent Mini.
An array of 160 computers is going to throw a lot of heat. To provide sufficient airflow, [Steve] built a custom cooling door out of four car radiators fans, connected to a 40A DC motor controller. This was all integrated into the door of the rack.
Another challenge was getting power to all of the Minis. Since this deisgn was for a data center, the Minis would have to draw power from a Power Distribution Unit (PDU). This would have required a lot of PDUs, and a lot of cables. The solution: a one to four Y cable for the Minis. This allows each shelf of four to plug into a single outlet.
The final result is a professional looking rack that can replace a rack of Xserves, and has capacity to be upgraded in the future.