Launch Controller Question

[Thunderbird]

I have built a launch controller that can switch between an internal "AA" 6V battery pack and a 12V car battery. It also has two momentary switches that have to be pushed simultaneously to launch the rocket. There is also a continuity circuit with a momentary switch that activates a piezo buzzer for continuity. After I built it, I realized that according to NAR specs, a key lockout must also be used. So I broke the positive circuit and placed a shorted mono phono plug in the line that must be inserted for launch. So, after reading all that, my question is: Does the continuity circuit also have to be locked out, even though it is drawing so little current that an accidental lauch cannot occur? It seems counter productive to have a continuity circuit that you cannot test while someone is at the pad, of course not with their face underneath the rocket!

 

[luke strawwalker]

So long as the circuit is physically incomplete when you remove the safety key, it meets the requirements of the safety code. By that I mean that the batteries are physically disconnected from the rest of the firing circuit when the key is removed, or the leads to the pad are disconnected from the circuit by the missing "key". That way the connection cannot be completed inadvertantly (like it could be with two momentary switches, which are still physically capable of being pushed by anyone who picks up the controller and fiddles with it while you're at the pad.

Clear as mud?? LOL

Later! OL JR

 

[shreadvector]

here is the answer in very few words:

When the "interlock" is removed, the circuit leading to the igniter must be dead.

That is why every commercial controller requires the insertion of the "key" before you can check continuity.

 

[Thunderbird]

Thanks, this answer clarifies it for me.
Tom

here is the answer in very few words:

When the "interlock" is removed, the circuit leading to the igniter must be dead.

That is why every commercial controller requires the insertion of the "key" before you can check continuity.