Spin Up An Old Hard Drive With A Solenoid Motor

February 21, 2015 by 12 Comments

Just about all of us have a few old hard drives in our junk box. There are a myriad of projects out there to put them to work in new and interesting ways. One of those ways is to turn your hard drive into a solenoid motor of sorts. (YouTube link) This isn’t a new hack, videos of it have been kicking around the internet for years. [black1985vette] gives a pretty good explanation of how he’s done it. He used a piece of brass as a connecting rod between the drive head and a pin mounted off-center to the platter hub. One of the platter mounting screws provides the perfect place to set the pin. A bent safety-pin rubs the center of the hub, which is partially insulated with tape. When the pin contacts the hub, the drive head is energized, pushing the whole assembly around. The mass of the platters acts as a flywheel, carrying the motor the rest of the way around.

[Pulverrostmannen] performed a similar mod, though he used a micro switch to time the drive head. Rather than a brass connecting rod, [Pulverrostmannen] used a spare head. With a simple transistor circuit acting as a speed control, his hard drive motor revved up to around 1560 RPM, which is pretty respectable for a bunch of junk parts.

So next time you’re stuck in on cold rainy weekend, pull out some of those old drives and get hacking! Click past the break to several of these projects in action.

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Play Music With Your Painting Using Teensy

February 21, 2015 by 5 Comments

[sab-art], a collaboration between [Sophia Brueckner] and [Eric Rosenbaum], has created a touch-sensitive musical painting. Initially, basic acrylic paint is used for the majority of the canvas. Once that is dry, conductive paint is used to make the shapes that will be used for the capacitive touch sensing. As an added step to increase the robustness, nails are hammered through each painted shape and connected with wiring in the back of the painting. These wires are then connected to the inputs of a Teensy++ 2.0, using Arduino code based on MaKey MaKey to output MIDI. The MIDI is then sent to a Mac Mini which then synthesizes the sound using Ableton Live.  Any MIDI-processing software would work, though. For this particular painting, external speakers are used, but incorporating speakers into your own composition is certainly possible.

A nice aspect of this project is that it can be as simple or as complex as you choose. Multiple conductive shapes can be connected through the back to the same Teensy input so that they play the same sound. While [sab-art] went with a more abstract look, this can be used with any style. Imagine taking a painting of Dogs Playing Poker and having each dog bark in its respective breed’s manner when you touch it, or having spaceships make “pew pew” noises. For a truly meta moment, an interactive MIDI painting of a MIDI keyboard would be sublime. [sab-art] is refining the process with each new painting, so even more imaginative musical works of art are on the horizon. We can’t wait to see and hear them!

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Pain Box Project

Making The Dune “Pain Box” A Reality

February 21, 2015 by 57 Comments

If you are unfamiliar with Dune, then you may not know what the pain box is. The pain box is a fictional device that produces an excruciating burning sensation without causing any actual damage. [Bryan] has been working on a project to duplicate this effect in the real world. It sounds like he may be on the right path by using the “thermal grill illusion”.

The thermal grill illusion is a sensory trick originally demonstrated back in 1896. The trick is made up of two interlaced grills. One is cool to the touch, and the other is warm. If the user touches a single grill, they won’t experience any pain because neither temperature is very extreme. However if the user places their hand over the interlaced grills simultaneously they will immediately experience a burning heat. This usually causes the person to pull their hand away immediately. It’s a fun trick and you can sometimes see examples of it at science museums.

The thermal grill illusion sounded like the perfect way to make the pain box a reality. [Bryan] has set specific constraints on this build to make it more true to the Dune series. He wants to ensure the entire package fits into a small box, just big enough to place an adult hand inside. He also wants to keep safety in mind, since it has the potential to actually cause harm if it were to overheat.

[Bryan] has so far tried two methods with varying success. The first attempt involved using several thermoelectric coolers (TECs). [Bryan] had seen PCBs etched a certain way allowing them to radiate heat. We’ve seen this before in 3D printer surfaces. He figured if they could become hot, then why couldn’t they become cold too? His idea was very simple. He etched a PCB that had just two large copper pours. Each one branched out into “fingers” making up the grill.

Each side of the grill ultimately lead to a flat surface to which a TEC was mounted. One side was cold and the other was hot. Heat sinks we attached to the open side of the TECs to help with performance. Unfortunately this design didn’t work. The temperature was not conducted down to the fingers at all. The back side of the PCB did get hot and cold directly under the TECs, but that wouldn’t work for this illusion.

The latest version of the project scraps the PCB idea and uses small diameter copper tubing for the grill. [Bryan] is working with two closed loop water systems. One is for warm water and the other is for cold. He’s using an aquarium pump to circulate the water and the TECs to actually heat or cool the water. The idea is that the water will change the temperature of the copper tubing as it flows through.

While the results so far are better than the previous revision, unfortunately this version is having problems of its own. The hot water eventually gets too hot, and it takes over an hour for it to heat up in the first place. On top of that, the cold water never quite gets cold enough. Despite these problems, [Bryan] is hopefully he can get this concept working. He has several ideas for improvements listed on his blog. Maybe some Hackaday readers can come up with some clever solutions to help this project come to fruition.

Plastic Mallet

Turning Plastic Milk Jugs Into A Useful Tool

February 21, 2015 by 29 Comments

[Peter] obviously enjoys getting to work in his wood shop. He also likes turning things into other things. With his latest project, he combines his two hobbies by turning plastic milk jugs into a plastic joiner’s mallet.

[Peter] started out by collecting and “processing” the milk jugs. Milk jugs are commonly made with HDPE. HDPE is a petroleum-based plastic with a high strength-to-density ratio. It’s easy to recycle, which makes it perfect for this type of project. We’ve even seen this stuff recycled into 3D printer filament in the past. The “processing” routine actually just consists of cutting apart the jugs with a razor blade. [Peter] mentions in the past that he’s used a blender to do this with much success, but he’s unfortunately been banned from using the blender.

Next, all of the plastic pieces are piled up on a metal try to placed into a small toaster oven. They are melted into one relatively flat, solid chunk. This process is performed three times. The final step was to pile all three chunks on top of each other and melt them into one massive chunk of plastic.

While waiting for the plastic to melt together, [Peter] got to work on the handle. He put his woodworking skills to good use by carving out a nice wooden handle from a piece of cherry wood.  The handle was carefully shaped and sanded with a variety of tools. It is finished with some linseed oil for a nice professional look.

When the plastic was mostly melted together, [Peter] had to get to work quickly while the plastic was still soft. He pried the plastic off of the metal tray and stuffed it into a rectangular mold he made from some fiber board. He used a heat gun to soften the plastic as needed while he crammed it all into the mold. With the mold suitably stuffed, he closed it up and clamped it all shut.

Once the plastic cooled, [Peter] had to cut it into the correct shape and size. He took the solid chunk of plastic to his band saw to cut all the appropriate angles. He then used both a drill press and a chisel to cut the rectangular mounting hole for the handle. The plastic piece was then shaped into its final form using a belt sander. All that [Peter] had left to do was slide it up and only the handle. The shape of the handle and mounting hole prevent the plastic piece from flying off of the top of the handle. Check out the video below to see the whole process. Continue reading “Turning Plastic Milk Jugs Into A Useful Tool” →

How I Learned To Stop Worrying And Love My 3D Printer

February 20, 2015 by 55 Comments

So, you’re thinking about finally buying a 3D printer? All the cool kids have one. Plus, how hard can it be anyways? Well, before you pull the trigger, it might be best to read this cautionary tale of one user’s experience in getting started with his first 3D printer.

[Scott Hanselman] is a programmer and teacher who started out with zero knowledge of 3D printing. In his informative (and somewhat humorous) blog post, you can follow along with [Scott] hour-by-hour as he unravels the some of the common mysteries that almost everyone will encounter with their first 3D printer.

His adventure begins with the frustration of z-axis calibration, an important part of any 3D printer. Some of the newer printers are automating this step (as well as bed-leveling) with sensors and clever software, but even then it might need small tweaks to lay down the all-important first layer. By hour five with his new printer, this slight annoyance turns into disgruntlement, as he finds that although there is tons of documentation on-line, a lot of it can be outdated or simply unhelpful.

In the end, [Scott] got his printer up and running, and learned a lot along the way.  We bet you can too – with a little effort that is. As the quality of printers on the market keeps going up, and the price continuing to fall for an entry-level printer, now might be the perfect time for you to get started. But you might want to read [Scott’s] journey to help manage your out-of-the-box expectations.

Plant Watering System

Automated Plant Watering System Uses Car Parts

February 20, 2015 by 16 Comments

[Shane] recently built an automated plant watering system for his home. We’ve seen several similar projects before, but none of them worked quite like this one. Shane’s system is not hooked into the house plumbing and it doesn’t use any off-the-shelf electronic valves.

Instead, [Shane’s] build revolves around a device that looks like it was intended to spray weed killer. The unit works sort of like a Super Soaker. The user fills the jug with water and then pumps a handle multiple times to build up some pressure inside the jug. Then a button can be pressed and the air pressure forces water out of the nozzle. [Shane] came up with a way to automate all of these mechanical motions.

First [Shane] had to find a way to pump up the bottle. He purchased a car door electronic lock actuator from eBay. It’s a pretty simple device. It’s just a DC motor with a gear box that turns the rotational motion of the motor into linear motion. This is mounted to a wooden jig and attached to the pump. A dsPIC microcontroller rotates the motor back and forth, which in turn pumps up the bottle.

The dsPic is also hooked up to a small servo. The servo is mounted to the same wooden jig as the car door actuator. A small arm is mounted to the servo so that when it rotates, the arm presses the pressure release button. This sends the water out of the bottles nozzle. [Pat] hooked up a small length of hose to the nozzle so he can direct the water into his plants. The video below demonstrates how the unit works. Continue reading “Automated Plant Watering System Uses Car Parts” →

Hardware for a ST4 to USB interface

Cheap USB Control For Your Telescope

February 20, 2015 by 23 Comments

There’s many complex systems for automatically pointing a telescope at an object in the sky, but most of them are too expensive for the amateur astronomer. [Kevin]’s Arduino ST4 interface lets you connect your PC to a reasonably priced motorized telescope mount, without ripping it apart.

The ST4 port is a very basic interface. There’s one pin per direction that the mount can move, and a common pin. This port can be added to just about any motorized mount with some modification to the controller. To connect to an Arduino, a TLP521-4 quad optoisolator is used. This keeps the Arduino and PC fully isolated from the motor circuits. but lets the Arduino take control of the mount.

With the hardware in place, [Kevin] cranked out some software which is available on Google Code. A simple Arduino sketch provides the USB interface, and a custom driver allows the ASCOM Platform to control the mount. Since many astronomy software tools support ASCOM, this allows the mount to be controlled by existing software.

With the interface in place, the mount can be used to find objects (GOTO) and automatically follow them with high accuracy (autoguiding). You can watch the telescope move on its own after the break.

Continue reading “Cheap USB Control For Your Telescope” →