Slow day at the office? Here’s a trick that’ll make your coworkers smile. Dangerously Fun has a guide to build a homopolar motor from a battery, copper wire, and magnet. A homopolor motor doesn’t rely on electromagnets in an armature changing their polarity to force a rotation movement compared to stationary magnets. Instead, they use an electrical current’s orientation to a magnetic field to provide a repulsive or rotational force. In this implementation, the current moves through a loops of copper wire from one pole of a battery to the other. A rare-earth magnet on one pole of the battery provides the magnetic field.
After the break we’ve embedded video of this simple example as well as a few more complex homopolar examples such as a five speed version. The motor in action certainly brings a smile to our faces and places this firmly in the useless machines family of hacks.
Analog clocks now a days get no respect. Everyone is digital this, or binary that, and we admit it is nice to look over and see the time promptly displayed. But there’s something about the quiet ticking and ominous feeling you get when around a large intricate clock that you know some serious time has been invested.
Nostalgia feelings aside, [Alan] from Hacked Gadgets introduced us to his Gear Clock. While it’s not a new idea, and in fact we have a few around the office, his concept really inspired us. His clock is driven via stepper motor and a PIC, allowing for the time to be fairly accurate. The only small problem he mentions is the poor paint job, but we think it looks amazing regardless.
Want to enter your hidden lair in style? Well [Jimmy] simply wanted to create a cool prop for his school’s homecoming dance. This project includes some obvious inspiration from Wayne Manor. [Jimmy] wired up the automated entrance with a 12VDC motor. In order for it to be able to push the door , the motor had to be attached to a gearbox, which directly powered a wheel. Current consumption issues were solved by using a wall-wart. Because a real bookshelf would still be too heavy, [Jimmy] dressed up a regular door with some patterned wallpaper to give it the right look. Coupled with a Shakespearean bust concealing the button, and some other cosmetic touches, this project was sure to impress any student who knew its secret.
We’ve covered weed whacker bicycles before and you can even buy 66cc conversion kits now. [geoff390] posted a few videos over on YouTube about another motor option. In the first video embedded below, he goes over the basic parts of his bike. The chainsaw motor is mounted to the side of the back tire and a metal drive wheel extending from the chainsaw shaft makes contact with it. The motor assembly is mounted on a hinge and the friction between the drive wheel and the back tire is adjusted with a turnbuckle. He posted a more detailed second video in which he goes over some of the finer details of the bike and some of the issues he’s had. Read the rest of this entry »
This antenna tuner is controlled remotely using geared motors and legos. The tuner needed to be closer to the antenna for performance reasons. This created a problem; most of the radio gear is inside while the tuner is outside. The gear motors and Legos combine to form a closed loop servo, operating two air core caps and an inductor switch. A control box placed near the radio is hard wired to the modded tuner outside. We would like to see something like this under gesture control using the Wii MotionPlus + Arduino.
[Humberto] from NerdKits sends in the newest addition to their excellent collection of videos. This video goes over the basics of DC motor control with microcontrollers. They begin by showing nine experiments and observations that can be done by the average hacker with a multimeter, motor, LED, and jumperwire. Using the results from these they show how to model and calculate the properties of a motor. Lastly, it shows how to control a motor using PWM. They have supplemental text and demonstration code for an ATmega168 on their website.
What you see above is the culmination of [Zach Smith]’s work building a pinch wheel style extruder for the RepRap. The current RepRap 3D printer uses a screw mechanism to push 3mm polymer filament into a heating barrel where it is melted and then extruded through a fine nozzle. [Zach]’s new version uses a drive gear from SDP/SI mounted directly to the DC motor we saw him teardown earlier. He’s redesigned the carrier for the extruder as well. It’s now much lighter and has provisions for mounting current and future controller electronics along with a magnetic rotary encoder. In the last two days, he’s been doing real world testing. It’s been doing well, but he’s learning to do things like always using a full spool and not trying to run short lengths back to back.
[glacialwanderer], who you may remember from his CNC machine build, recently completed an electric spinning wheel. Spinning wheels are used by knitters to turn raw sheep’s wool into yarn. He went through several iterations before arriving at a good design. Besides the motor, there are two major components to the spinning wheel: the flyer and the bobbin. A Scotch tension brake is used to slow the rotation of the bobbin in relation to the flyer. This causes the wool to twist as it’s pulled on.
He initially tried to just use a dimmer switch with an AC motor. That quickly burnt up. The next version used a sewing machine motor since they’re designed with a variable speed control. Unfortunately, it didn’t have enough torque at low speeds. The final design used a DC motor with a SyRen motor controller. It offered plenty of power and at ~$150 it’s still less than the cheapest commercial models on eBay. You can see a video of it and the spinning process embedded below.
We’ve served up dozens if not hundreds of machines with a practical purpose, but we are always interested in machines like those [Steven Laurie] makes, which serve no other purpose than looking impressive, spewing smoke, leaving tire marks, and making a lot of racket. We’ll give you the scoop on Steve’s motor art after the break.
Perhaps you’ve seen this image before: a young kid tooling around on a pair of inline skates, pushed forward by a weed whacker cycle. While the instructions for this device would seem fairly obvious (attach wheel to weed whacker) the writeup appears to be nonexistent. If you have any information, do let us know, but in the meantime, enjoy these other weed whacker powered projects.
