Projectile Speed Sensor

September 7, 2010 by Mike Szczys 16 Comments

[Mike] built a sensor rig to measure projectile speed. The setup uses a tunnel with two sensors in it. Each consists of a laser diode on one side focused on a photodiode in the other. The two are monitored by an op amp and measured by an ATmega128 microcontroller. When the beams are broken the elapsed time between the two events is measured in order to calculate speed. There is a setting to adjust the calibration for a range of speeds, which came in quite handy as [Mike] initially tested the device with rubber bands before moving on to a pellet gun and then a rifle.

It seems like he’s tempting fate by shooting a target just a few inches below his exposed circuitry but his marksmanship prevailed. We’ve seen bullet speed detectors in the past, used just for the delight of seeing how fast the projectile is moving, and also to capture an impact at just the right instant.

Equinox Clock

September 7, 2010 by Mike Szczys 34 Comments

The Equinox clock is made up of simple parts but a combination of fine design and precision make it a gem of a timepiece. The guts are made up of an Arduino, a DS1307 real time clock, twelve LED drivers, and sixty RGB LEDs. These combine with a capacitive touch interface to tell the time using three lit blocks for the hours, one for the minutes, and a fading block for the seconds. See for yourself after the break.

To our delight, [Bram Knaapen] shared the specifics of the case. The black ring that makes up the body was laser cut and spray painted. He uses small blocks of acrylic that have been sandblasted to diffuse the light. This is also a great example of clean circuitry using interconnects between the different circuit boards.

We always enjoy seeing clocks no matter what level of finish is involved, but great design is something that makes us want to hang a project on the wall rather than stow it in a parts bin.

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1953 Radio Includes Tubes, AM, FM, And MP3

September 7, 2010 by Mike Szczys 16 Comments

This vintage radio can play AM, FM, and MP3, all with a classic sound. Inside you’ll find a new AM radio tube-amp, providing the functionality you’d expect from the device. The rest of it comes from a conglomeration of parts; an FM receiver board from another radio and an MP3 player with remote control and USB connector. The classic sound we mentioned above comes from an AM modulator. That’s right, the auxiliary audio boards aren’t connected directly, but are broadcast on the AM band so that your latest MC Lars album has the same sound quality as the traffic report.

Check out this similar project from last year that adds RDS to a vintage radio.

Snake Bot Climbs Trees

September 6, 2010 by Caleb Kraft 27 Comments

While you are out enjoying your Labor Day festivities, keep an eye out for robot snakes in the trees. The CMU robotics lab has built a snake bot named Uncle Sam that can climb trees and poles. As you can see in the video after the break, the bot seems to have no problem at all scaling a tree. It wraps itself around the tree, then rotates down the center of its entire body. Once it has reached the top, it can take in the scenery. Though it is a little creepy looking, at least it isn’t in the water.

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Self Playing Bayan Built Nearly 22 Years Ago

September 5, 2010 by Jakob Griffith 57 Comments

The year is 1988, where a Russian engineer [Vladimir Demin] has combined a Bayan, or button accordion, with several (we lost count at about 96) solenoids. If that alone doesn’t blow your mind the computer, also hand built by [Vladimir], controls the whole process leaving the operator to only work the bellows. Putting truth to the fact in Soviet Russia, accordion plays you. We wish we could find some more information about the instrument, but curse our inability to read Russian. Alas check after the break for a shorter version of the video in the link above.

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Solid Ice Beer Caddy

September 5, 2010 by Caleb Kraft 31 Comments

brrrrr

[Rob] has made an astounding contribution in the effort to keep our libations chilled. Not content with merely refrigerating his cold ones, or even putting them in a cooler full of ice, he has built a beer caddy out of solid ice. Though it may look simple initially, you can see from his writeup that it actually took quite a few itterations to get it to freeze correctly, and then actually survive the process of removing the bottle placeholders. Ultimately, he found that glass bottles full of sand work best and you have to freeze the caddy in layers. Though he calls himself an impatient person, we’ve seen people who insisted on having their cold ones made frigid faster. You can see a video of the ice caddy after the break.

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Binary Calculator

September 4, 2010 by Caleb Kraft 20 Comments

oooh, love those blue LEDs

[Syst3mX] emailed us about his Binary Calculator earlier this week and it almost slipped into the depths of our inbox. Luckily We noticed it in there today and thought we’d share.

He wanted to be able to calculate binary values without having to jump through hoops or boot up his computer, so he built his own binary calculator. For the brains, he chose an ATTiny2313. He can do basic operations like NOT, AND, OR, XOR, addition, subtraction, multiplication, division and modulo. It isn’t too bad looking either. You can catch a video of it in action after the break.

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