Coil gun with parts pulled from an electric stapler

[Lou’s] latest tutorial details the process of turning an electric stapler into a coil gun. The stapler is the expensive part, but the rest is pretty simple. He used PVC pipe and a handful of fittings along with a few supplies you probably have kicking around your shop.

It’s surprising how perfect the Bostitch stapler (from which the parts were pulled) is for this project. The mechanism that drives the staples into your pages uses a solenoid with a rather large coil. To turn it into a coil gun you simply need to replace the core of the solenoid with a metal projectile. In the video after the break [Lou] shows us how to make a barrel onto which the coil can be mounted. From there he uses a wooden spacer to position a hunk of smooth metal from a bolt which serves as the projectile. The stapler’s original drive circuitry and trigger mechanism do the rest.

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Watering system for your vegetable garden

The vegetables will be alive when [Dillon Nichols] returns from vacation thanks to this automatic watering controller that he built. This is the second iteration of the project, and deals mainly with replacing the electronics and UI of the controller itself. He detailed the hardware used for watering in a previous post. He plumbed in a solenoid valve with a hose threading on the output end for the soaker hoses snaking through the garden beds. This is a normally open valve but we’d suggest using a normally closed valve as a power outage will let the hose run continuously.

[Dillon] prototyped the design on an Arduino board, then moved to a standalone ATmega328 chip on some protoboard for the final design. He used a 3D printer to make the custom face plate which allows access to the three control buttons and provides a place for the character LCD to be mounted. In addition to the timer settings there is a manual watering switch as well. He used a typical mains light switch, wiring it with a pull-down resistor to make it work well with the Arduino. His explanation of the timer system can be seen after the break.

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Any flavor sports drink at the push of a button

[Sage Spate] wasn’t happy with the boring flavors of orange, blue, or red sports drinks. He decided to mix it up by building this flavor-mixing drink dispenser.

He modified the caps for each bottle to work with an air-pressure system. This way the bottles themselves serve as the reservoir and can easily be replaced when empty. Each cap has two openings, one is used by the dispenser nozzle and includes a hose that will reach all the way to the bottom of the bottle. The other hole connects to an air pump. Raising the pressure in the bottle forces sports drink up and out of the dispenser hose.

One air pump is used for all three reservoirs with a set of solenoids to enable each flavor individually. [Andreas] sent in the tip and mentioned that some of the parts are salvaged from an ink jet printer but we’re not sure which ones. At any rate, the next step in the project is to add Arduino control which will allow for custom mixing based on preset recipes.

We’ve embedded the demo video after the break.

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A look inside what makes cruise control work

[Todd Harrison] took a look inside the business end of the cruise control system from his 1994 Jeep Grand Cherokee. We were a bit surprised at how the system operates. The parts seen in the image above make up the throttle control, using a trio of solenoids to vary the level of vacuum inside the device.

We categorized this as a repair hack, but [Todd] is just rubbernecking and doesn’t have any real plan to fix the system. It’s been on the fritz for ten years and this piece may not even be the culprit. But we’re still satisfied because he gives us a look at the system which uses the amber-colored stoppers on the three solenoids to plug three different sizes of weep holes. The unit is a vacuum enclosure where a throttle wire connects to a rubber diaphragm and adjust engine speed as the diaphragm moves. The vehicle’s computer actuates the three solenoids, allowing leakage to vary the level of vacuum, thereby keeping the throttle at just the right level. Neat!

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Turning a bunch of solenoids into a performance of Stomp

Say you have a handful of solenoids, a copy of MaxMSP, an Arduino, and access to a whole bunch of parts in a textile museum. What do you do? If you’re like [Luke], you’ll probably come up with an Arduinofied performance of Stomp, played on dozens of old gears, light fixtures, and various other metal parts.

To control what noise sounds when, [Luke] used a Touch OSC interface running on an iPad to send MIDI information to Ableton. From there, MAX/MSP sends messages to an Arduino to actuate the solenoids on cue. The interface is set up so anyone can make their own compositions by reusing patterns into loops of solenoids making noise. Sure, it’s not the dulcet tones you would expect from a more traditional instrument, but [Luke] manages to put on a good show.

While [Luke]’s instrument may sound overly mechanical and dissonant, it’s entirely possible to replace the objects he’s hitting with the solenoids with something a little more melodious. Putting a few solenoids in a cave wouldn’t be a bad idea; too bad it’s already been done.

A closer looks helps you build your own DiWire Bender

Whether or not you’re actually going to build this CNC wire bender, we think you’ll love getting a closer look at how it’s put together. The team over at PENSA got such a strong response from a look at the original machine that they decided to film a video (embedded after the break) showing how the thing was put together. They’ve also posted a repository with code, bom, etc.

In the image above [Marco] shows off the portion that actually does the bending. It’s designed to mount on the pipe through which the straightened wire is fed. The 3d printed mounting bracket really makes this a lot easier. The assembly provides a place to attach the solenoid which moves a bearing in and out of position. That bearing presses against the wire to do the bending, but must be moved from one side of the wire to the other depending on the direction of the next bend. This is a lot easier to understand after watching the demo video which is also embedded after the break.

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Shake phone to start scooter

This scooter starts right up with a shake of your Android device. This shake must be done from front-to-back, because a side-to-side shake is reserved for unlocking the saddle ([Brad] stores his helmet within).

Connectivity is facilitated over Bluetooth, with a rocker switch near the left handle bar to disable the receiver so that you don’t run down the battery. You can see the locking panel hanging open on the front portion of the scooter. Inside he installed the driver board which patches into the ignition system and drives a solenoid for the seat latch. It sounds like the latching mechanism used a bowden cable whose handle was inside that locking panel. By adding a solenoid and generously lubricating the cable he  managed to get it functioning from the driver board.

Check out the video after the break for a proper demonstration. The phone is running a Python script via SL4A, which takes care of the user interface.

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