High Voltage: Build Your Own 84 KV Lightning Stick

August 24, 2011 by Mike Szczys 6 Comments

There’s a proverb that says ‘Speak softly and carry a big stick’. Now that stick can come in a high-voltage form factor. The device above, which reminds us of a side-handled baton with a coke can stuck on the end, is a portable Van de Graaff generator.

Although debated in the comments, the creator of this hack claims you can shock someone with 84 kV of electricity using the device. Of course as a weapon it’s lacking since we’re talking about static electricity; the voltage can be through the roof but the current is extremely low. Despite that, there are some fun things you can do with them. The video after the break show it throwing off sparks with the lights dimmed. [Yardleydobon] also includes a few other tricks at the end of his tutorial. He makes a set of Franklin Bells using two more soda cans with the aluminum tab from one suspended in between them. As he charges it up, the tab dances back and forth, ringing the ‘bells’ it runs into. Once they are charged, the ringing can be restarted by discharging just one of the cans.

Continue reading “High Voltage: Build Your Own 84 KV Lightning Stick” →

Can A Dippy Bird Be Used As A Temperature Sensor?

August 23, 2011 by Mike Szczys 9 Comments

Dippy birds are the toys that teeter-totter back and forth as the beak of bird-shaped body dips into a container of water. The felt covering the beak and head picks up water and, through evaporation, cools that end of the glass tubing. The temperature changes cause the dichloromethane to either boil off, or condense, shifting the weight of the liquid thereby pivoting the glass body.

The real question is, does the temperature of the water cause the toy to move differently, and can that be measured to calculate the temperature of the water? [Craig] put that query to the test, by designing an apparatus to measure the motion of a Dippy Bird. A photointerruptor was used to measure the motion of the body, causing an interrupt each time the tail of the bird passes in between the sensor and the emitter. For control data a DS1820 temperature sensor was positioned near the felt on the head of the bird, and a relative humidity sensor captured readings at the same time. Data from the three inputs was collected over a two-day period. Although not a precise measurement, the motion of the bird did trend in the same ways that were recorded by the temperature and relative humidity sensors.

DIY RC Sensor Board

August 18, 2011 by Mike Nathan 5 Comments

diy_telemetry_sensor_board_hitec_aurora

Along with hobby electronics, flying RC planes is one of [Diederich’s] favorite hobbies. When out in the field, he prefers to use an Aurora 9 radio controller, and while the remote is great, he was a bit disappointed in Hitec’s telemetry sensor lineup. He says that the sensors are pretty decent, though limited, and he was positive he could build a better telemetry solution.

His sensor board is completely open source, and comes with a long list of features. First and foremost, it emulates all of the messages that can be sent to the radio controller by Hitec’s off the shelf models, making it a simple drop-in replacement. He uses an ATMega8L microcontroller to run the show, including all sorts of input pins and connectors to support GPS as well as voltage and current monitoring.

He has made a DIY kit available for purchase online, but all of the sensor’s schematics and a BOM are available for free, should you desire to roll your own.

We love seeing DIYers show up manufacturers in this way, especially when they share the goods with their fellow hobbyists. Nice job!

Electric Longboard Uses DIY Hub Motors

August 17, 2011 by Brian Benchoff 12 Comments

As a student of MIT, [Jed Storey] has access to a ton of machine tools, so he decided to build an electric longboard with hub motors by hand. He wound up re-doing a lot of his project, so we can commiserate with him on the trials of R&D.

Inspired by the BWD scooter, [Jed]‘s longboard uses hub motors – the wheel is the motor. The rotors were fabricated in-house, and off-the-shelf stators were wound by [Jed] by hand. There’s a lot of work that went into this build, and the build log is really fascinating in this regard.

The board is controlled by a pistol-grip R/C controller that had been modified to include a dev board and an XBee. For power, an aluminum enclosure was fabricated, strapped underneath the deck, and filled with LiPo batteries. While the build is mostly done, [Jeb] is thinking about scrapping it and moving onto version 2, the HeavyBoard. Check out the video of the board in action.

Two-axis Panning Time Lapse Rig Built From Lego

August 12, 2011 by Mike Nathan 14 Comments

2_axis_lego_timelapse_dolly

[Jochem] wrote in to share a neat time lapse camera dolly he constructed out of Lego bricks. He is a big fan of the two-axis panning time lapse effect where the camera moves while recording images. He figured it would be easy enough to construct one of his own, so he dug out his pail of Lego and got to work.

The rig consists of a stationary motor platform which pulls a movable sled using a simple gear and string. The motor platform is controlled by an Arduino, which pulls the movable sled along every so often, snapping pictures along the way. [Jochem’s] Nikon D80 supports shutter release via IR, so he programmed the Arduino to send a quick IR pulse each time it has finished moving the dolly.

The rig looks like it works pretty well as you can see by the video below, but [Jochem] says that it still needs a bit of work. We just can’t wait to see what other time lapse movies he puts together once he finds an “interesting” time lapse subject.

Continue reading “Two-axis Panning Time Lapse Rig Built From Lego” →

Persistence Of Vision Helicopter Blades With RGB LEDs

August 12, 2011 by Brian Benchoff 17 Comments

A user named [BOcnc] on the rcgroups forums just posted his RGB POV helicopter blades.

The two blades are attached to the heli just as any other whirlygig. The electronics, though, are mounted underneath the blade with a battery pack. We covered a build last year that demonstrated weight added to a spinning blade won’t tear everything apart, but that build used only blue LEDs. This build is full color and makes us feel like we’re living in a cyberpunk future populated by Recognizers and Daft Punk.

The images are stored on an SD card that receives data from a USB port. The microcontroller is a PIC32, and from what we can assume from the schematics, the RPM of the blades is measured by an on-board hall effect sensor (don’t quote us on that, though). There’s no hope of a commercial release from [BOcnc], though. He can’t find anyone to manufacture the blades, and the entire build was too expensive. It sure looks pretty though, so check out the video of it after the break.

Continue reading “Persistence Of Vision Helicopter Blades With RGB LEDs” →

Portal Puppet Probably Won’t Kill Us

August 11, 2011 by Brian Benchoff 11 Comments

This incredibly detailed puppet of the Wheatley from Portal was sent into us, and we a so very happy that we’re not writing about a GLaDOS build right now.

Hewn from florist foam and covered Wonderflex and Apoxie Sculpt, Wheatley pretty much tows the line as far as cosplay and prop builds go. What makes Wheatley interesting is his movement mechanism – he’s actually a hand-controlled puppet. Portal quotes come a small sound module that plays 10 Wheatley quotes. The control system has ten buttons and allows for the display of a lot more emotion than we would expect from a talking sphere. We really like the completely manual solution to an articulated robot eyeball – a really great, simple solution to a complex problem.

Like the portal turret and the adorable and friendly companion cube, we’re really impressed with the build quality of Wheatley. Yet again we’re left wondering why Valve doesn’t license some awesome toys like their office sentry.

Check out the intelligence dampening sphere in action after the break.

Continue reading “Portal Puppet Probably Won’t Kill Us” →