Linear Motor Can Be Built From Trash

October 9, 2011 by Brian Benchoff 13 Comments

[Raul] built a cheap linear actuator out of a drawer slide and a surplus flatbed scanner.

A few builds we’ve seen, like the PCB drill press or the horribly inefficient thermostat, used linear actuators as key components of their builds. These linear actuators are fairly expensive compared to other parts we usually have lying around so going the homebrew route to reduce costs is always a welcome idea.

The first step of [Raul]’s build is to mount a drawer slide to a piece of wood. A stepper motor is attached to one end of the actuator and a timing belt is strung along the length of the assemblage. After a bracket is connected the drawer slide and the belt, you’ve got a very inexpensive linear motor.

In our days of dumpster diving, we can’t count the number of times we’ve passed up on drawer slides in unwanted furniture. Stepper motors, gear trains and timing belts from old ScanJets can be found for pocket change any day of the week. For cheap and accurate linear motion, we couldn’t come up with a build that does better than [Raul]’s.

Sustainability Hacks: Automatic Window Control

September 29, 2011 by Brian Benchoff 43 Comments

Sometimes, changing one little bit of a green hack turns it into a build that wastes as much energy as our gaming rig. [Dr. West]’s automatic window controller is one of these builds. The good news is the window controller can be easily modified to cut energy costs in the fall and spring.

[Dr. West] doesn’t have any control over the heat in his apartment and for the entire Canadian winter, his apartment gets really hot. He doesn’t pay for his heat, so he does what any of us would do – crack a window. Inspired by this post, he put a linear actuator in the frame of his kitchen window. [Dr. West] didn’t want to damage the window frame, so he attached the actuator to a piece of square aluminum tubing that mounts to the existing screw holes.

The electronics, [Dr. West] used a Rabbit 2000 dev board, LCD display and keypad, and built an H-bridge circuit on a bit of breadboard. Because of a port conflict and admitted laziness, an Arduino is used to read the thermistor. The display shows the current and desired temperature, and the Rabbit opens and closes the window accordingly. All the source code is posted in the forum post.

While it’s not the most ‘green’ idea to dump heat from a building’s HVAC system out into a frozen tundra, this would be a great build to automatically open and close windows in the more temperate seasons. Open windows during the day, close them at night and you’ll have no more problems coming home to a house that’s either too hot or too cold. Check out a video of the automatic window after the break.

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Motion Detecting Window Closers Keep Train Noise At Bay

September 13, 2011 by Mike Nathan 57 Comments

motion_detecting_window_closers

[Ed Rogers] has the unfortunate privilege of living right next to a set of train tracks, and as a man who holds his sleep in high regard, he needed to find a way to keep the noise in his bedroom to a minimum. To combat the sound of passing trains, he built himself a system that automatically closes his windows when a train passes by his apartment.

The setup relies on a web cam, which uses motion-sensing software to detect a passing train. The video is analyzed by a computer in his room which passes a message to an Arduino when a train is near. The Arduino then sends a pair of window mounted linear actuators into action, slowly (and quietly) shutting his windows.

The linear actuators move pretty slowly as you can see in the video below, but we doubt that matters. Since it looks like [Ed] lives in a slow zone, it likely takes quite a bit of time for a freight train to pass, making the 40-second closing period more than reasonable.

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Servo Hacked Linear Actuator

January 19, 2010 by Jakob Griffith 22 Comments

[AntonB] has modified a servo into a powerful linear actuator (think: changing rotational motion into linear motion). The process is simple enough, modify a servo for continuous rotation and then add the custom built actuating shaft. You do of course lose the precision of the servo, but a small price to pay to be able to lift ~20 pounds straight up. Inspiration for such a cheap solution came from his Planetary Surface Exploration Rover. Check out a video of both after the break.

[Thanks Eric]

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