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DaveP

Member Since: September 11, 2008

Country: United States

  • “No disassemble!”

  • Hmmm… not sure that the T5403 is well suited for high-altitude balloon work; the datasheet indicates that the low end of its sensitivity is at 300hPa, or approx. 9.1km / 30,000 ft. For reference, StillDavid’s flight that reached 130,000 feet would have seen something like 3.5hPa.

  • Love the easter egg, guys - very nice. Merry Christmas, and a Happy New Year!

  • Nice! Congrats on another successful flight… it’s always nice when the last-minute mechanical design (and associated code change) works. Well done.

  • The unfortunately discontinued Sparkfun Atari Missile Command workshop.

  • There are a couple of groups discussing doing just that on diydrones.com, and there’s also a commercial solution to do that from GPS Boomerang. I would caution, though, that the regulations are unclear at best for attempting such a flight in the US National Airspace.

  • Congrats again, guys - it was a blast to launch with you! For what it’s worth, the ArduSat payload looks like it worked flawlessly… more details will be coming from them soon, but you can check out the results of one of their (SFE-provided) cameras here: http://twitpic.com/b80kzy.

    Also, if you’re interested in the writeup of the EDGE flight specifically, check out the EDGE3 Mission Summary.

    UPDATE: Some ArduSat data can be found in NanoSatisifi’s writeup.

  • I checked current draw at both 3.7V and 4.0V, as well as with and without the LED, and didn’t notice a significant difference with or without the LED in place. A full writeup of the work that my team and I did with this camera (as well as information about the flight) can be found here (link to the HackHD review towards the bottom of the page): EDGE2 Flight Summary. I’ve only just started the public documentation process for this flight, so the payload info will be fleshed out over the next couple of weeks.

    Interesting that you got a C4 card to work… I’ll have to try again with mine.

  • My team and I just flew this camera on a high-altitude balloon (HAB) here in Colorado over labor day weekend, and we were very impressed. The dynamic range on the camera is fantastic - a HAB flight has everything from looking straight at the sun to looking into “black space,” and this camera handled the transitions reasonably quickly and the scenes where the extremes were combined were well balanced with fine detail still very clear. We’ll get a link to the video up as soon as we’re done editing.

    Over the space of 2.5 hours, we consumed 1660 mAH out of the single-cell lipo we were using, for an average of around 650mA current requirement during recording. When I hooked it up to my benchtop power supply, it looks like the current draw is a little bit bursty, bouncing between 600 and 700 mA rapidly during recording (perhaps buffering up data and then dumping it to the card).

    Definitely get a good high-speed SD card for this camera - Class 4 doesn’t cut it (I didn’t expect it to, but wanted to try it anyway). Using a slow card results in stuttering video; we flew a Class 10 16g uSD, and saw about 13.4GB consumed over the 2.45 hour recording time.

  • All right - numbers are good! For a 10dBm (10mW) Tx with a 9dBi Tx antenna and just a touch of cable loss for good measure, I’m coming up with approx. 20dBi of Rx gain required for a comfortable fade margin at 50 miles out (just the baseline distance that I use), which is going to be a huge helical antenna with a pretty narrow beam. Difficult, but not impossible… here’s another online calculator, this one for helical antennas: http://www.daycounter.com/Calculators/Helical-Antenna-Design-Calculator.phtml On your blog, you mention that the easyradio units are 433Mhz… all of the calculations that I’ve done so far are for 900MHz, which has substantially higher free space path loss. I just mention it becaus it’s a fairly substantial difference (50 miles = approx. 130dBm loss @ 900MHz, 123dBm loss @ 433)… let me know. Also, FWIW, it may be possible to line up some additional equipment donations for you… I sent some contact info to the email address on your blog. Good luck!

Engineering Boot Camp 1

DaveP 15 items

All of the parts and pieces that you need for the EDGE Research …