This project is a really simple accelerometer based altimeter. The assembled board only weighs 10grams; the power supply is an additional 6grams. The data collection is done by a Basic Stamp II. It records 1 second before and 11 seconds after it detects the initial launch thrust. On their first launch they got some legitimate looking data (it would have been nice if they had an inclinometer to compare it to). The second launch resulted in a catastrophic engine failure on the pad. It’s a shame they couldn’t do more testing, but at least they’ve got video. Schematics and source code natch.
The photo above is from a recent BoingBoing post on high power rocketry.
High powered rocketry is amazing. I’ll try to dig up some of my pictures from last year.
“Unblowupable is a word that’s thrown around alot lately…”
how can it record one second of data before it launches? can it read minds or something?
Hey that’s right!
I was under the impression that the temporal stuff needed much bigger batteries.
“how can it record one second of data before it launches? can it read minds or something?”
I think it continuously records the reading and then forgets the reading
Once it see a spark in acceleration then it tells it to “keep” the data one second before the spark.
To record one second before the launch and 11 after you just use a 12 second “circular” buffer. That means as soon as the deviced is armed for launch you record continuously in the 12 second buffer, going around memory in a circle, constantly overwriting the old data. When you detect the launch, you mark that spot in the circle as second 0, and stop recording after 11 seconds, leaving one second of data from before launch sitting before the point you marked as the lanuch time (second 0).
Is this why we saved all those rockets from the 4-H rocketry projects?