Comments on: Hacking a scale to test rocket motors

By: jd

jd — Wed, 24 Nov 2010 11:45:00 +0000

An evolved version of this rocket motor test system is on http://www.soldersmell.com/blog/?p=20

By: Ryan

Ryan — Fri, 05 Sep 2008 03:05:38 +0000

Did a similar project as a high school science project 20+ years ago.

We attached a long arm to an Atari video game paddle and attached the rocket to the end of the arm. When the rocket fired, it moved the arm and turned the paddle. A couple of springs resisted the thrust.

Data was collected 116 x per second on an apple IIe.

Our thrust curves were nonsense until we finally (it took us high school kids weeks) figured out that we had to subtract the sinusoidal oscillation of the spring.

By: Sparky

Sparky — Mon, 01 Sep 2008 11:35:40 +0000

I once build something like this for a friend, but out method was a bit different; we used a slide and a spring with a known stiffness constant, and used the guts of an old ball mouse and a very simple hacked together program to measure the displacement. We used this to measure the impulse of bottle rockets.

You just need to get relative movements, not absolute position, to prevent clipping at the edge of the screen.

By: mischa

mischa — Sat, 30 Aug 2008 23:01:19 +0000

there was already the same project done by a german hacker:
http://fingers-welt.de/gallerie/eigen/elektro/waage/waage.htm
AFAIK you already posted a project of him hete

By: Satiagraha

Satiagraha — Sat, 30 Aug 2008 03:54:38 +0000

Bravo to them. That's a really nifty and easy way to add some good information to your hobby

:thumbsup:

By: Caleb Kraft

Caleb Kraft — Fri, 29 Aug 2008 23:42:59 +0000

Thanks forrest. It has been corrected.

By: Forrest Voight

Forrest Voight — Fri, 29 Aug 2008 22:58:38 +0000

The article said a PIC 18F2550, not a PIC 1852550.