Electronic Launch control Article

I just completed an article where I built an electronic launch control for model rockets.
See it here: http://kronosrobotics.com/gl/article.php?story 040425002727697

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On Sun, 25 Apr 2004 01:55:31 -0400, "Michael Simpson"

Looks nice, but if it were me I would want S1 to be spring return too. The way you have it means that once the unit is armed, the relay is under software control alone.
Also, how much current does it put through the igniters, while testing continuity?
--
Darren J Longhorn http://www.geocities.com/darrenlonghorn /
NSRG #005 http://www.northstarrocketry.org.uk /
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320ua
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Interesting, and very well documented.
But, hmmm....
With many igniters drawing more than 9amps for 2 seconds or more (there's a plasma created when the thing goes off that keeps a 'short' circuit even after the igniter has 'opened up') it seems like you might get a bad voltage drop on VDD... which will reset your processor.
Seems like the batteries might be a pain to get to...
I would humbly suggest the following for "Launch Controller II"
1. Add a "Battery Test" indicator for the Internal Batteries. 2. Add battery charge circuitry for the internal batteries charge with 12vdc or a wall-wart. 3. Consider using an easily accessible External Battery(s) for the Igniters. 4. Consider adding a "Battery Test" indicator for the External Battery(s). (If you decide on a standard 9volt battery for the external igniter battery, you could also test other rocketeers batteries before they attempt launch... you'd become VERY popular!!!)
You might also consider using Li-Poly or Li-Ion battery's... no memory problem, more available currant, more environmentally friendly, (and yeah, much more expensive).
Thanks again!
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a
voltage
This launcher was designd for Small engines up to C size. We have yet to have a problem. If you get a dead short and the power drops below 2.5v the proccessor resets and kills the relay. A small routine at the keeps the unit from arming againd if the button is still pressed,
Later I may build a launch unit that has small batt for logic controll and larger battery for igniter but wont do it until I get my electroinc launch pad finished. It's going to have servos for leveling and wind dir and speed indicators.
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Interesting chip, the Athena etc. good prices compared to stamps. are they the same syntax or close to stamps ?

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Speaking of BASIC Stamps...
Is anyone here doing anything rocketry related with stamps? I've recently started playing with them and have a few ideas developing but I'd like to hear what others have done (are doing) with them.
Mario Perdue NAR #22012 Sr. L2 for email drop the planet
http://roci.indyrockets.org "X-ray-Delta-One, this is Mission Control, two-one-five-six, transmission concluded."
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Very similar syntax. Much of it has been simplified. It not a stamp clone. There are two chips The Dios which is the flagship. This chip was developed for engineers and robotics tinkerers. It runs about 10 times faster than the stamp and has floating point variables and strings. While the language is Basic like the stamp its more like VB because you can have functions and libraries.
The Athena was developed to get people started into microcontrollers. It has the same kind of program model as the stamp but costs a lot less. The compile is also free was designed for beginners as well,
We are releasing a new chip in the next month called the Perseus. This chip is much like the Athena but has an 8 channel AtoD. It also has commands for native RS485.

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Would it be easy to port to a PIC.

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Very.
I've used 'PicBasic' with a good deal of success on the 16F84 and other microchip products.

control
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Best I give it a go then, I am still green when it comes to programming PIC/PICbasic but we shall see how we get on with F628

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Good luck, and have fun!

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