10-06-2017, 03:32 PM
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Master Modeler
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Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
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Quote:
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Originally Posted by astronwolf
How will your WiFi switch achieve all of Rule 3 of the NAR model rocket safety code?
Ignition System. I will launch my rockets with an electrical launch system and electrical motor igniters. My launch system will have a safety interlock in series with the launch switch, and will use a launch switch that returns to the “off” position when released.
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I see no insurmountable problems here. The WiFi radio system ignites the rocket motor electrically, by passing current through an electrical igniter; the radio link merely takes the place of ignition lead wires between the launch controller and the rocket on its launcher, and:
The safety interlock can also function over a radio link. A relay that closes the launch battery/igniter circuit at the launch pad doesn't activate until the properly-coded radio signal, received by the receiver, triggers this function. When the radio signal ceases (or its coded "message" changes, when the launch button on the hand-held transmitter is released), the relay's coil is de-energized and its contacts (in the launch battery/igniter circuit) go open, preventing any more current from flowing in that circuit (if the igniter failed to burn through and physically break, that is). Also:
The length of time that the relay contacts are held closed (to allow current to flow in the battery/igniter circuit, to launch the model) could be programmed via software. As an additional safety feature, I would include a "pull-out" plug and jack in the battery/igniter circuit (a mono audio plug with "shorted" contacts [under its threaded-on cap] would suffice for such a plug). In the event of a misfire, after waiting one minute, one could walk to the launcher and pull out the plug (which could have a 15' length of brightly-colored string tied to it and laid out on the ground extending away from the launcher). |