Designing and building a bench supply

[Scott’s] been digging around the back issues of the Internet to find this project. He blew the dust off and sent us a link to an article that traverses the design and build process of a bench power supply.

[Guido Socher] does an excellent job of presenting his bench supply project. So many others show of the final product, but he has gone out of his way to make sure we understand the design principles that went into it. He starts off by talking about the simplest possible supply design: a transistor and Zener diode which generates a reference voltage. He goes on to discuss the problems with this simplified circuit and how to address them, covering the gotchas that pop up at each step in the process.

Once he designed the circuit and laid out some boards he began building an enclosure. We love his tip about using a stick pin and an unpopulated through-hole PCB to mark button locations on the front bezel of the case. The final design is shown above, and includes a laptop brick to translate mains power into a 24V 3A DC feed for his custom circuitry.

Create and Conflagrate giant modeled sculptures with Kinect and CNC

Summer has hit, and with it a bunch of crazy people going to crazy festivals and (often) burning crazy sculptures to crazy music! In that vein [Matthew Goodman] recently got involved in the burning flipside community down in Texas for his first big effigy build.  The project called for a gigantic archway flanked by two human shaped figures, since he had been working in Kinect [Matt] decided to try his hand at physically modeling the figures from Kinect mesh data.

After co-registering the depth and image cameras, setting up a capture routine to record, getting  .ply based meshes from the depth camera, and making a keypoint detector [Matt] was ready to start getting real world data from the Kinect. Armed with a ghetto steadycam built from his local Austin Hackerspace‘s spare parts bin, [Matt] proceeded to collect three 1.5 gigabyte scans of the charming [KT], who served as a model for the sculpture.

Once the meshes were imported to sketchup they could be merged and smoothed into a coherent form. The figure was split into CNC-able parts (known as the “lady bits” by [Matt] and his crew) and sent to local makers [Dave Umlas] and [Marrilee Ratcliff]’s ShopBot CNC mill. The 400 some odd bits of wood were then carted to flipside, methodically set up, and promptly set aflame the end of the event.

We have seen a couple of really interesting burning man projects, but this is possibly the shortest lived end result. Stay tuned this summer for more insane Black Rock City bound creations as well. Also don’t forget to check out [Matt]’s site for more details.

VU meter lives in a Linksys housing

[Dillon] just finished his first project of the summer. It’s a volume units meter for his sound system and it has a few tricks up its sleeve.

He’s driving the rows of LEDs using an AN6884 LED driver chip. It has an integrated amplifier circuit which makes it the perfect part for building a VU display. He had a broken Linksys 5-port switch sitting around which he used as the enclosure for the project. It has just enough room to incorporate a speaker in case he wants to take the meter on the road with him. But when at home he can choose to use his stereo system instead with the flip of a switch. To ensure he’s making the most out of the 5-bit precision he’s included a voltage divider that can be adjusted with a potentiometer. We’ve embedded a video after the break which shows how well it works.

Looking for a bit more inspiration for your own VU meter project? Check out this RGB version.

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Tiny transforming beer can robot


The next time you reach for a cold one, you might want to take a look at the can to ensure that your beer won’t suddenly sprout legs and start skittering across the table.

You might remember [Ron Tajima] from some of his previous creations, including this Roomba-based baby cradle and the PacMan Roomba mod. This time around, he has created a cool little transforming robot that fits inside a beer can.

The robot’s brains are stored just underneath the top of the beer can on a custom-built board. On one side of this board, you will find an mbed controller which is used to manage all of the robot’s functions, and on the other side, four batteries provide all of the device’s power. The robot’s three legs are controlled by six servos, allowing for movement in several different planes. The beer-bot’s movements are controlled with a Wiimote, so we’re assuming he has crammed a Bluetooth module somewhere in there as well.

[Ron] mentions that it moves a bit slowly when standing on end, but we think the robot is pretty awesome as is, and we can’t wait to see what improvements the next version might bring.

Stick around to see a video demonstration of the robot in action.

[Thanks Sascha]

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Machine precisely, methodically arranges water droplets


While some projects we feature are meant to perform a useful function or make life easier, others such as this art installation by [Pe Lang] are far less functional, but amazing nonetheless.

Taking a cue from CNC-style machines, his creation is an experiment in falling objects and the properties of water. The machine methodically moves along a small 370 x 330 mm plate that is constructed out of a special omniphobic material. A syringe full of water travels along with the machine’s arm, depositing a single 3.3 mm wide drop of water on the board every few seconds as it moves along. Due to the surface tension of the water, each droplet forms a near perfect sphere on the plate without disturbing any of its neighbors.

Once the machine is finished, it leaves the matrix of water droplets to evaporate, after which the machine starts its careful process once again. It really is amazing, regardless of the fact that it doesn’t exactly “do anything”.

Be sure to check out the video below to see the exhibit in action.

[via Make]

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Android controlled labyrinth

[Pcdevltd] pulled an all-nighter to get his first Android Developer Kit project up and running. Basing the project off of the example that Google used when unveiling the new accessory development hardware, he set to work controlling a marble labyrinth game using his smart phone. What began at 7pm was wrapped up by 5am to produce the results seen in the video after the break.

These ball mazes use two knobs to pivot the playing surface, changing gravity’s pull on the ball to get it to go where you want. [Pcdevltd] pulled off the bottom on his labyrinth and installed two small servo motors. These connect to the Android Open Accessory Development Kit via a small cable. Connect that to the phone and you can then use the internal accelerometer to play the game. If you have an Android phone and an Arduino this should be pretty easy to replicate since we know you can already use the ADK with Arduino. Get to work on your own projects and don’t forget to send us a link to your project log.

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DIY Earthquake Detector

Some animals seem to be able to detect earthquakes. Some animals also navigate using the earth’s magnetic field. From the idea that there may be some relationship with these two things, this experimental earthquake detector was born.  [Bob Davis] built this device, which uses an Arduino and several Hall effect sensors to detect and record magnetic fields. Possibly after enough data is recorded, a correlation can be found between the two phenomena.

The sensors in this device are arranged to measure magnetism in four directions as well as in the vertical axis. Part of the idea behind this is that before an earthquake the quartz in the ground moves producing a magnetic field.

In the video after the break, Bob gives some background on the theory behind this device and talks about the first version (built way back in the year 2000) which uses a PC for control and recording. Really interesting stuff so be sure to listen to Bob’s explanation after the break. Continue reading “DIY Earthquake Detector”