The DIY Open Crank Engine Moped

Anyone can strap a two-stroke engine on a bicycle to create a moped. But [robinhooodvsyou] has created something infinitely more awesome. He’s built an inverted open crank engine on a 10 speed bicycle. (YouTube link)  As the name implies, the engine has no crankcase. The crankshaft, camshaft, and just about everything not in the combustion chamber hangs out in the open where it can be seen and appreciated.

[robinhooodvsyou] started with an air-cooled Volkswagen cylinder. He filled the jug with a piston from a diesel car. Camshaft, flywheel, valves, and magneto are courtesy of an old Briggs and Stratton engine. The cylinder head, crankshaft, pushrods, and the engine frame itself are all homemade.

Being an open crank engine, lubrication is an issue. The crankshaft’s ball bearing is lubricated by some thick oil in a gravity fed cup. Even though the engine is a four-stroke,[robinhooodvsyou] adds some oil to the gas to keep the rings happy. The camshaft and connecting rod use Babbit bearings. While they don’t have an automatic oiling system, they do look pretty well lubricated in the video.

Starting the engine is a breeze. [robinhooodvsyou] created a lever which holds the exhaust valve open. This acts as a compression release. He also has a lever which lifts the entire engine and friction drive off the rear wheel. All one has to do is pedal up to cruising speed, engage the friction drive, then disengage the compression release.

We seriously love this hack. Sure, it’s not a practical vehicle, but it works – and from the looks of the video, it works rather well. The unmuffled pops of that low 4:1 compression engine reminds us of old stationary engines. The only thing we can think to add to [robinhooodvsyou’s] creation is a good set of brakes!

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Controlling a Quadcopter with Gestures

[grassjelly] has been hard at work building a wearable device that uses gestures to control quadcopter motion. The goal of the project is to design a controller that allows the user to intuitively control the motion of a quadcopter. Based on the demonstration video below, we’d say they hit the nail on the head. The controller runs off an Arduino Pro Mini-5v powered by two small coin cell batteries. It contains an accelerometer and an ultrasonic distance sensor.

The controller allows the quadcopter to mimic the orientation of the user’s hand. The user holds their hand out in front of them, parallel to the floor. When the hand is tilted in any direction, the quadcopter copies the motion and will tilt the same way. The amount of pitch and roll is limited by software, likely preventing the user from over-correcting and crashing the machine. The user can also raise or lower their hand to control the altitude of the copter.

[grassjelly] has made all of the code and schematics available via github.

Kickstarter Monitor Will Brighten Your Day

Keeping up with a kickstarter campaign can be quite a task, especially if your project is real (looking at you, Scribble Pen!) and you’re trying to keep up with product fabrication and all the other logistics involved in bringing a product to market. [macetech] are currently in the middle of a campaign themselves and built a loud, bright alert system to notify them of any new kickstarter backers.

The project uses a LED marquee to display the current number of backers, but every time a new backer contributes to the project, a blindingly bright green arrow traffic signal is illuminated and a piezo speaker plays a celebration tune. All of these devices are controlled by an Arduino Yun which, with its built-in Atheros chipset, easily connects to the network and monitors the kickstarter page for changes.

[macetech] used some interesting hardware to get everything to work together. They used a USB-to-RS232 cable with and FTDI chip to drive the LED marquee and a PowerSwitchTail 2 from Adafruit to drive the power-hungry traffic signal. Everything was put together in a presentable way for their workshop and works great! All of the source code is available on their project page, and you can check out their RGB LED Shades kickstarter campaign too.

Microbial Fuel Cell with a Side of Betta Fish

Move over, potato batteries: DIY microbial fuel cells are here to stay! A microbial fuel cell (MFC) is a device that uses bacteria in an anaerobic (oxygen-poor) environment to convert chemical energy into electricity. [drdan152] posted steps on how to make a soil-based MFC  with a neat twist: it’s also a fishbowl for a betta fish.

[drdan152] used soil from the wetlands, referred to as “muck.” This nutrient-rich soil provided a hearty supply of bacteria, especially Geobacter species, known for their uncanny ability to transport electrons outside their cells using bacterial nanowires. The proton exchange membrane (PEM) was made up of salt, water, and agar. After some initial runs, [drdan152] determined that flat char cloth made the best anode, while red copper wire served as the cathode. Assembling the MFC was as simple as surrounding the anode with a thick layer of muck on all sides, adding the PEM on top, followed by water. The cathode was situated halfway out of the water.

After a couple of days, the voltage increased in proportion to the amount of bacteria growing on the anode. The betta fish can happily live in this habitat for a short period of time(it still has to be fed, of course), and the bacteria certainly won’t mind – the fish’s excrement provides an additional food supply. As a bonus, the water is kept clean. However, like any aquarium, the water will need to be changed periodically as carbon dioxide byproduct accumulates from the fish’s respiration and the MFC (high carbon dioxide levels = dead betta fish).

The MFC generates 725 mV. [drdan152] is not satisfied with that number, and is testing out charge pump circuits to generate as much as 3V. We are looking forward to seeing the results. We also wonder if a small aquatic plant could help make it a more self-sustaining environment for the fish. In the meantime, [drdan152] is encouraging others to try larger-scale versions of this MFC. Perhaps MFC-powered carnivorous robots doubling as mobile aquariums are in our near future.

Game Tin: Handheld Games with no Batteries

Anyone who grew up with a Game Boy knows how well they sucked through AA batteries. [Nick]’s Game Tin console solves this problem by running of an ultracapacitor charged by solar power.

The console is based on a EFM32 microcontroller: an ARM device designed for low power applications. The 128×128 pixel monochrome memory display provides low-fi graphics while maintaining low power consumption.

There’s two solar cells and a BQ25570 energy harvesting IC to charge the ultracap. This chip takes care of maximum power point tracking to get the most out of the solar cells. If it’s dark out, the device can be charged in about 30 seconds by connecting USB power.

The 10 F Maxwell ultracapacitor can run a game on the device for 1.5 hours without sunlight, and the device runs indefinitely in the sun. Thanks to the memory display, applications that have lower refresh rates will have much lower power consumption.

The Game Tin is open source, and is being developed using KiCad. You can grab all the EDA files from Bitbucket. [Nick] is also gauging interest in the Game Tin, and hopes to release it as a kit.

Fail of the Week: [Chris] vs. The Gorn

This week, [Chris] tips the scales but ultimately fails. He’s on the road, hacking through the Great White North and improvising from a poorly-lit echo chamber that happens to have a vise.

Knowing nothing about firearms (do you believe that?), he decided to build a BB cannon out of pure scrap. Several kinds of sparks fly, starting with a Hitachi drill-as-lathe and ending with a tiny cupcake sparkler. [Chris] proceeds to bore out some redi-rod by eyeballing it and offers helpful tips for course correction should you attempt same. Having centered the cavity, he drills out a tiny hole for a fuse.

His first fuse is of the crushed up match head paste variety. It burns kind of slowly and does not launch the BB. Naturally, Plan B is to make napalm glue to adhere Pyrodex pistol powder to paper. As you might imagine, it worked quite well. The wadding was singed, but still no joy. After packing her full of propellant, it still didn’t explode and merely burned out the blowhole. So, what gives? Insufficient barrel length? Should have used bamboo instead of redi-rod? Didn’t want it badly enough? Give us your fodder below.

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Hackaday Munich — Get Your Ticket Now!

If you’re anywhere remotely near Munich in November you’re not going to want to miss this. Hackaday is throwing our first European event! The fun runs from 12:30-23:30 on Thursday, November 13th, 2014.

Take the afternoon off of work

Tell your boss this is professional development, then grab all your hacking gear and head on down to Technikum at the Munich Kultfabrik.

Our set of workshops will test your embedded skills whether you’re a beginner or seasoned veteran. These include controlling small robots, working with audio processing from a Moog synth, reverse engineering some mystery hardware, and trying your hand at machine vision.

Try win the afternoon’s challenges. Implement the fastest and most reliable robot brain, design the best Moog synth add-on circuit. Or prove your logic skills by coding a perfect Computer Vision game solver. We’ll bring some prizes for those that show the most clever and impressive skill.

Take in the talks and learn the winner of The Hackaday Prize

Beginning at 19:00 we present a couple of talks about embedded hardware sure to impress the most discerning of hackers. Immediately following we will announce the Grand Prize winner of the 2014 Hackaday Prize. This Open Hardware build is the project that made it through more than 800 entries to secure a trip into space and eternal recognition from the Hackaday community.

Finish the day with a party

Finally, we’ll dim the lights and turn up the music for The Hackaday Prize Party. Enjoy some food and beverages, get yourself 3D scanned, try your hand at some vintage video games, and enjoy the company of the Hackaday Community. In attendance will be [Mike Szczys], [Brian Benchoff], [Aleksandar Bradic], [Jasmine Brackett], and [Ben Delarre].

We’ll see you there!