From: Bdale Garbee Date: Thu, 19 Nov 2009 23:23:00 +0000 (-0700) Subject: new blog entry X-Git-Url: https://git.gag.com/?p=web%2Fgag.com;a=commitdiff_plain;h=20dd352c9c90eb9d9a493ea2986e06ed02721572 new blog entry --- diff --git a/bdale/blog/posts/TeleMetrum_Progress.mdwn b/bdale/blog/posts/TeleMetrum_Progress.mdwn new file mode 100644 index 0000000..59a6437 --- /dev/null +++ b/bdale/blog/posts/TeleMetrum_Progress.mdwn @@ -0,0 +1,67 @@ +[[!tag tags/rockets]] +[Keith](http://keithp.com/keithp) and I have been pretty quiet about +[TeleMetrum](http://www.altusmetrum.org/TeleMetrum/) for a while... but that +doesn't mean we've been idle! + +In recent weeks, I've built up several more flight units and two more ground +station boards, as noted in my +[production log](http://www.altusmetrum.org/TeleMetrum/production). +We're both trusting rockets solely to our boards and Keith's firmware +at this point. In fact, we've accumulated a significant number of succesful +flights, including a cool drag-race between 4" airframes +at [NCR](http://ncrocketry.org) +[Oktoberfest](http://ncrocketry.org/modules.php?name=Oktoberfest) +where we both put brand-new, nearly identical rockets fully at risk flying +only TeleMetrum boards, and a flight by Keith the same weekend on a full-K +[Loki](http://lokiresearch.com) K350W moon-burner in which he set a new +personal altitude record! I've also flown a board with 100-g accelerometer +installed successfully in a flight that peaked at 52.8 g! + +We're now hard at work on a "next version" of the hardware, incorporating +everything we've learned so far. There are a number of significant changes +planned: + + Fully integrated, on-board GPS receiver and patch antenna, with + support for off-board amplified antennas when airframe geometry + or materials demand it. + + A change in the design of the circuit for firing e-matches to + ignite ejection charges that will improve mechanical reliability, + plus explicit support for using a separate pyro battery if desired. + + Inclusion of a "companion board interface" that we envision using + for a pyro channel expansion board to support staging and air + starts, among other things. + + Dramatic increase in the capacity of the on-board data logging memory. + + Changes in connector series to eliminate our dependency on expensive + crimping tools for making cables. + +To make all this fit, I'm stretching the board an extra 1/4 inch to a total +outline of 1 by 2.75 inches. We're also moving all the connectors, the GPS +patch antenna, and the beeper to the "back side" of the PC board. This is a +win on several levels... it will allow us to have silk-screen labels for the +connectors, will help protect the baro sensor from sunlight and the various +surface mount parts from physical damage during rocket prep, and opens up more +board surface area for component placement and routing on the "top side" of +the board. In practice, this means that boards will be mounted on standoffs +with all the active components facing "down" and the connectors facing "up." + +Before we'll be ready to build some of these, we need to get in some more +flights to test the various changes we're making. In particular, the change +in ejection charge circuit, and the GPS receiver chip and antenna choices +we're now favoring. Unfortunately, Keith and I are now both into the time of +year where launch opportunities come less frequently, even before we consider +the weather. + +Meanwhile, Keith's firmware and ground station software are now doing nearly +everything we've envisioned wanting from this project. It seems entirely +likely that he'll be ready to declare "version 1.0" soon after we obtain and +verify the functionality of our next version of the hardware... + +In the meantime, our friends at [Woot](http://woot.com) have posted a +[really funny video](http://www.woot.com/Forums/ViewPost.aspx?PostID=3564356) +combining material from a couple launches this summer of my +[10-inch Goblin](http://www.gag.com/rockets/projects/goblin10/), on one of +which we flew some of their screaming flying monkey dolls... Enjoy!