Unicorn Build Report

My Little Pony poised under the drill pressHere’s a status update on that Unicorn Build we undertook a couple of Sundays ago. We started by opening up this Chicago Tool soldering iron, which wasn’t trivial! Armed with a Dremel rotary tool and a succession of cutting wheels, we tore into the plastic handle to reveal these innards. Having separated the core from the handle, we went on to test the thermal insulating adequacy of some mica tape with a thermal conductivity of 0.173 BTU that we thought we might use to buffer the plastic My Little Pony from the heat of the soldering iron. When we wrapped the lower end of the soldering iron core in several layers of the tape and turned it on, though, the tape was quite hot to the touch. Time to try something else for insulation; we’ll be trying wool felt next.

In the course of fiddling with the soldering iron’s core, we inadvertently jiggled loose a wire that’s meant to connect somewhere inside the core that’s pretty much inaccessible without cutting into some solid-looking metal and potentially rupturing some more connections. Fortunately, we had a second cheap soldering iron on hand for just such an eventuality. This Weller model was far easier to open and—unlike the Chicago Tool one—sports a metal flange that presents an obvious way to connect to the Pony’s forehead.

Meanwhile, the Pony underwent the first of what will probably be several surgeries. :)

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Spaceblimp test launch report

HacDC launched its first near-space balloon this past Saturday as part of a contest called Hackerspaces in Space that challenges hackerspaces around the world “to send a weather balloon, with payload, into near-space to capture pictures of the Earth’s horizon, to return the payload safely to the ground, and to retrieve the payload.”

To avoid Washington, DC-area restricted airspace and the Chesapeake Bay, given the southeasterly winds, the balloon was launched from rural Edinburg, Virginia. The payload included a camera running CHDK, a GPS receiver, and a transmitter sending APRS packets containing position information so we could track and recover it. The electronics were encased in a foam shell tethered to a parachute and the helium-filled balloon, which we calculated would burst at around 80-85K feet, around the same altitude at which we had a nichrome wire set to cut the balloon free if it hadn’t yet burst.

Here’s a map plotting the position data received from the balloon’s payload. Somewhere in the course of the flight it seems to have stopped transmitting, so the recovery team relied on the last-known and predicted positions to try to receive some potentially-degraded signal, but none was detected. The payload has not yet been recovered, though it’s still possible someone will find it on their property and call one of the contact numbers listed on the outside.

Photos of the launch and recovery effort by Katie, Mark, and Bryce—who also posted a personal account of the day’s events—are online.

The team is tentatively planning a second launch with a newly-assembled payload on Sunday, 15 August.

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The Gentle Hackers’ Literary Salon: Makers

HacDC will hold the first Gentle Hackers’ Literary Salon at 7:00 p.m. on Tuesday, 16 March 2010. We will be discussing Cory Doctorow’s 2009 Creative Commons-licensed science fiction novel Makers. You can read the dead-tree version or download it for free. The salon will be a casual, minimally-structured discussion of the book. Light refreshments will be available. Steampunk attire optional. :)

This event is free and open to the public.





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