A Pedal Powered Cinema

May 10, 2015 by Rick Osgood 10 Comments

When the apocalypse hits and your power goes out, how are you going to keep yourself entertained? If you are lucky enough to be friends with [stopsendingmejunk], you can just hop on his pedal powered cinema and watch whatever movies you have stored on digital media.

This unit is built around an ordinary bicycle. A friction drive is used to generate the electricity via pedal power. In order to accomplish this, a custom steel stand was fabricated together in order to lift the rear wheel off the ground. A 24V 200W motor is used as the generator. [stopsendingmejunk] manufactured a custom spindle for the motor shaft. The spindle is made from a skateboard wheel. The motor is mounted in such a way that it can be lowered to rub the skateboard wheel against the bicycle wheel. This way when the rear bicycle wheel spins, it also rotates the motor. The motor can be lifted out of the way when cruising around if desired.

The power generated from the motor first runs through a regulator. This takes the variable voltage from the generator and smooths it out to a nice even power signal. This regulated power then charges two Goal Zero Sherpa 100 lithium batteries. The batteries allow for a buffer to allow the movie to continue playing while changing riders. The batteries then power the Optomo 750 projector as well as a set of speakers.

Hackaday Prize Entry: Open Source Diesel

May 9, 2015 by Brian Benchoff 72 Comments

There are plans for open hardware farming equipment that can be brought to third world countries to relieve the beasts of burden and increase the production of fields. Want an open source car? You can 3D print one. Just about anything you can strap a motor to has been replicated in open hardware; all you need to do is buy a motor and bolt it on.

But what about the motors themselves? For his entry to The Hackaday Prize, [Shane] is designing an open source engine. It’s small, it’s a two-stroke, and it’s diesel, but it’s completely open hardware; a great enabling project for all the open source dirt bikes and microcombines.

The design of [Shane]’s engine is based on the Junkers Jumo 205; a weird engine that had opposing pistons in one cylinder. This allows the engine to have variable compression, allowing for a wide variety of fuels to be used. If you have kerosene, that’ll work with this engine. French fry oil will as well. It’s exactly what you need for an engine that could be used for anything.

The 2015 Hackaday Prize is sponsored by:

Earth Day: Electric Vehicles

April 22, 2015 by Brian Benchoff 38 Comments

Electric vehicles are the wave of the future, whether it’s from sucking too much oil out of the ground, or because of improved battery technology. Most internal combustion engines are unsustainable, and if you’re thinking about the environment – or working on an entry for The Hackaday Prize – an electric vehicle is the way to go.

Here are a few electric vehicle projects that are competing in The Hackaday Prize that show off the possibilities for the electric vehicles of the future.

An Electric Ninja

Motorcycles are extremely efficient already, but if you want a torquey ride with a lot of acceleration, electric is the way to go. [ErikL] is hard at work transforming a 2005 Ninja 250R into an electric vehicle, both to get away from gas-sipping engines and as a really, really cool ride. Interestingly, the battery technology in this bike isn’t that advanced – it’s a lead acid battery, basically, that reduces the complexity of the build.

And They Have Molds To Make Another

Motorcycles aren’t for everybody, but neither are normal, everyday, electronic conversion cars. [MW Motors] is building a car from scratch. The body, the chassis, and the power train are all hand built.

The amazing part of this build is how they created the body. It’s a fiberglass mold that was pulled off of a model carved out of a huge block of foam. There’s a lot of composite work in here, and a lot of work had to happen before digging into the foam; you actually need to choose your accessories, lights, and other bits and bobs before designing the body panels.

While the suspension and a lot of the mechanical parts were taken from a Mazda Miata, the power and drive system are completely custom. Most of the chassis is filled with LiFeMnPO4 batteries, powering four hub motors in each wheel. It’s going to be an amazing car.

Custom, 3D Printed Electric Motors

If you’re designing an electric car, the biggest decision you’re going to make is what motor you’re going to use. This is a simple process: open up a few catalogs and see what manufacturers are offering. There’s another option: building your own motor. [Solenoid] is working on a piece of software that will calculate the specifications of a motor given specific dimensions. It will also generate files for a 3D printed motor given the desired specs. Yes, you’ll still need to wind a few miles of copper onto these parts, but it’s the beginning of completely custom electronic motors.

Powered Double Pendulum Is A Chaotic Display

February 25, 2015 by Rick Osgood 25 Comments

If you’ve never seen a double pendulum before, it’s basically just a pendulum with another pendulum attached to the end. You might not think that’s anything special, but these devices can exhibit extremely chaotic behavior if enough energy is put into the system. The result is often a display that draws attention. [David] wanted to build his own double pendulum display, but he wanted to make it drive itself. The result is a powered double pendulum.

There aren’t many build details here, but the device is simple enough that we can deduce how it works from the demonstration video. It’s broken into two main pieces; the frame and the pendulum. The frame appears to be made mostly from wood. The front plate is made of three layers sandwiched together. A slot is cut out of the middle to allow a rail to slide up and down linearly. The rail is designed in such a way that it fits between the outer layers of the front plate like a track.

The pendulum is attached to the linear rail. The rail moves up and down and puts energy into the pendulum. This causes the pendulum to actually move and generate the chaotic behavior. The rail slides up and down thanks to an electric motor mounted to the base. The mechanics work similar to a piston on a crankshaft. The motor looks as though it is mounted to a wooden bracket that was cut with precision on a laser cutter. The final product works well, though it is a bit noisy. We also wonder if the system would be even more fun to watch if the rotation of the motor had an element of randomness added to it. Or he could always attach a paint sprayer to the end. Continue reading “Powered Double Pendulum Is A Chaotic Display” →

A Single Pixel Digital Camera With Arduino

January 31, 2015 by Rick Osgood 29 Comments

[Jordan] managed to cobble together his own version of a low resolution digital camera using just a few components. The image generated is pretty low resolution and is only in grey scale, but it’s pretty impressive what can be done with some basic hardware.

The heart of the camera is the image sensor. Most consumer digital cameras have tons of tiny receptors all jammed into the sensor. This allows for a larger resolution image, capturing more detail in a smaller space. Unfortunately this also usually means a higher price tag. [Jordan’s] sensor includes just a single pixel. The sensor is really just an infrared photodiode inside of a tube. The diode is connected to an analog input pin on an Arduino. The sensor can be pointed at an object, and the Arduino can sense the brightness of that one point.

In order to compile an actual image, [Jordan] needs to obtain readings of multiple points. Most cameras do this using the large array of pixels. Since [Jordan’s] camera only has a single pixel, he has to move it around and take each reading one at a time. To accomplish this, the Arduino is hooked up to two servo motors. This allows the sensor to be aimed horizontally and vertically. The Arduino slowly scans the sensor in a grid, taking readings along the way. A Processing application then takes each reading and compiles the final image.

Since this camera compiles an image so slowly, it sometimes has a problem with varying brightness. [Jordan] noticed this issue when clouds would pass over while he was taking an image. To fix this problem, he added an ambient light sensor. The Arduino can detect the amount of overall ambient light and then adjust each reading to compensate. He says it’s not perfect but the results are still an improvement. Maybe next time he can try it in color.

Electric Chainsaw Teardown

June 24, 2014 by Eric Evenchick 67 Comments

An electric chainsaw with its case removed

For his Beyond Unboxing series, [Charles] tore apart a Ryobi cordless chainsaw to get a better look at how this battery powered tool works.

Inside he found a three-phase motor and controller. This motor looks like it could be useful in other projects since it has a standard shaft. The battery pack was popped open to reveal a set of LG Chem 21865 cells, and some management hardware.

With all the parts liberated from the original enclosure, [Charles] set up the motor, controller, and battery on the bench. With a scope connected, some characterization of the motor could be done. A load was applied by grabbing the spinning shaft with welding gloves. [Charles] admits that this isn’t the safest way to test a motor.

While it is a very fast motor, the cut-in speed was found to be rather low. That means it can’t start a vehicle from a stop, but could be useful on e-bikes or scooters which are push started.

This chainsaw a $200 motor, controller, and battery set that could be the basis of a DIY scooter. It sounds great too, as the video after the break demonstrates.

[Thanks to Dane for the tip!]

Continue reading “Electric Chainsaw Teardown” →

Arduino Controlled Dahlander Motor Switch

April 2, 2014 by Eric Evenchick 15 Comments

[Jean-Noel] is fixing a broken Lurem woodworking machine. This machine uses a three-phase Dahlander motor, which has three operation modes: stop, half speed, and full speed. The motor uses a special mechanical switch to select the operating mode. Unfortunately, the mechanical bits inside the switch were broken, and the motor couldn’t be turned on.

To solve the problem without sourcing a new switch, [Jean-Noel] built his own Arduino based Dahlander switch. This consists of three relays that select the wiring configuration for each speed mode. There’s also a button to toggle settings, and two lamps to show what mode the motor is currently in.

The Arduino runs a finite-state machine (FSM), ensuring that the device transitions through the modes in the correct order. This is quite important, since the motor could be damaged if certain restrictions aren’t followed. The state machine graph was generated using Fizzim, a free tool that generates not only FSM graphs, but also Verilog and VHDL code for the machines.

The final product is housed in a DIN rail case, which allows it to be securely mounted along with the rest of the wiring. The detailed write-up on this project explains all the details of the motor, and the challenges of building this replacement switch.