An Actively Cooled Cloud Chamber

This cloud chamber is designed to keep the environment friendly for observing ionizing radiation. The group over at the LVL1 Hackerspace put it together and posted everything you need to know to try it out for yourself.

A cloud chamber uses a layer of alcohol vapor as a visual indicator of ionizing particles. As the name suggests, this vapor looks much like a cloud and the particles rip though it like tiny bullets. You can’t see the particles, but the turbulence they cause in the vapor is quite visible. Check out the .GIF example linked at the very bottom of their writeup.

The chamber itself uses a Peltier cooler and a CPU heat sink. The mounting and insulation system is brilliant and we think it’s the most reliable way we’ve seen of putting one of these together. Just remember that you need a radioactive source inside the chamber or you’ll be waiting a long time to see any particles. They’re using a test source here, but we saw a cloud chamber at our own local Hackerspace that used thoriated tungsten welding rods which are slightly radioactive.

[Thanks JAC_101]

Garage Door Opener Used To Automatically Lower A Game Table Top

[Lou] is at it again, and this time he wrote in to let us know about his automated ping pong table topper. With no good spot to stash an entire extra table [Lou] decided to take a two in one game table approach and fit the top of the ping pong table to his pool table. A ping pong table top is no small thing though and it turns out the best (or maybe coolest) place to store it is above the ceiling! At the flip of a switch a garage door opener pulls away a section of ceiling tiles and a winch motor lowers the table top into place with two cables.

The system works very smoothly using some pretty easy to find parts. [Lou’s] instructional video (embedded after the break) shows the system in action and explains the concepts behind the automation. We aren’t sure how the winch stops lowering the table, but the ceiling section uses a light switch and spring combo as its limit switch. The only thing really missing is the flashing red light, industrial klaxon, and fog machine needed to compliment the screeching nightmare-howl of that winch motor.

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Wiper Motor Motion Simulator

[DERIY] set out to create a two degrees of freedom motion simulator for driving simulation. After four months, he’s completed this impressive simulator for about $400. The simulator receives driving data from the game and actuates the seat to provide tactile feedback to the driver.

To keep the costs low, he decided to use wiper motors for actuating the seat. The system is controlled by the Thanos AMC Motion Controller. This AVR based system connects over USB and controls the motor drivers. There’s also a collection of software for calibrating the system, including tuning the PID control and setting up the feedback potentiometers. An LCD display provides some information on the system status during operation.

If you’ve ever wanted to build a motion simulator, this is a good example of how to get started. The open source hardware for this makes controlling the system easier, and using readily available components can lower the build cost.

Check out a video of the simulator in action after the break.

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StarGate Eggbeater

[Jason] used a strip of 142 Adafruit LPD8806 Addressable RGB LEDs to create the StarGate Eggbeater persistence of vision display. The LED strips are controlled by an Arduino Mega, which is used to control the strip and provides 21 bit color control for each LED. The strip is housed into a ring-shaped tube which is mounted onto a rod and bearing to allow it to spin. A 1/4 HP motor is used to spin the ring at 250 RPM creating the POV effect.

One issue when controlling a spinning object is making electrical connections to a spinning object. The LPD8806 requires four connections: power, ground, clock, and data. To make the connections, [Jason] used a MOOG Slip Ring. This allows for the four connections to be made while the ring spins at 250 RPM.

Of course POV demos need videos, so check one out the “boss program” video after the break.

Via Adafruit

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UV LEDs Expose PCBs, Gives You A Tan

Among the projects that define electronic design, a UV exposure box is right up at the top of the list. These boxes shine UV light on a work piece and are used for everything from exposing photosensitive PCBs to erasing EPROMs. [carlolog] decided to build his own and ended up with a fairly impressive array of ultraviolet LEDs perfect for making PCBs or tanning the back of your hand.

One important thing to remember when making large arrays of LEDs is current consumption and power needed to light the device up. [carlolog] naive assessment of how much power would be required used a 12 volt supply with 135 LEDs and 135 resistors, wasting a lot of energy and producing 24 Watts of heat.

Of course this power consumption can be reduced by putting a few LEDs in series, so [carlolog] wired 3 LEDs together with a 150Ω resistor. This array requires just over 11 Watts and consumes less than 1 Amp; perfect for a desktop UV box.

The enclosure for the box was crafted out of three Ikea photo frames, and a small timer circuit powered by an ATmega8 was added. Now whenever [carlolog] needs to wipe an EPROM, he can put the chip in the box, set the timer, and walk away.

A very nice build, but when dealing with a lot of UV we must remind our readers: do not look into the UV array with your remaining eye.

Adding Digital Readout To A Non-CNC Mill

In the quest to add a digital readout to his mill, [Yuriy] has done a lot of homework. He’s sourced a trio of very capable scales, researched what kind of hardware his DRO should be based on, and even built a very cool display using seven-segment LEDs. After nearly a year of work, [Yuriy] finally hit upon something that works well: an Arduino and an Android tablet, perfectly matched for one of the prettiest machine shop displays we’ve ever seen.

[Yuriy] based his build off a trio of digital scales he bought from Grizzly. These scales bolt on to the frame of his mill and send data to their own display. An Arduino was used to pull the data off these scales and sent via Bluetooth to a Nexus 7 Android tablet.

Considering a DRO solely based on an Arduino and a character LCD would look a little chintzy – and the fact Arduinos can’t do floating point arithmetic – we’re really impressed with [Yuriy]’s very elegant solution.

Thanks [Lee] for sending this one in.

Turning A Shipping Container Into A 3D Printer

Built inside a 20-foot shipping container placed on its end, the Kamermaker – ” room maker” in Dutch – is one of the largest 3D printers we’ve ever seen. Able to print objects as big as 2 meter square and 3.5 meters high, the Kamermaker is designed to print huge objects including furniture, architectural elements, and even entire rooms.

The Kamermaker is a collaboration between Architectburo DUS and Utilimaker and the result of wanting to build the world’s largest 3D printer pavilion. Built inside a stainless steel-clad shipping container, the Kamermaker features a scaled-up version of the X, Y, and Z axes you’d find in any other 3D printer. The only change is a scaling up of current designs, allowing it to print small wind turbines covering its surface or, theoretically, a life-size TARDIS.

Because using traditional plastic filament would be prohibitively expensive, the Utilimaker team chose to extrude plastic pellets on the fly as it is used. There’s an excellent video of the filament extruder here along with a walk-through of the machine in operation after the break.

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