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Old 09-14-2021, 04:35 PM
luke strawwalker's Avatar
luke strawwalker luke strawwalker is offline
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Join Date: Dec 2007
Location: Needville and Shiner, TX
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Quote:
Originally Posted by stefanj
Since the pandemic started our club started using, for our outreach launches, Estes controllers and pads in a "misfire alley" setup.

I thought it would be cool to make heavier-duty panels for the launches, and remembered this thread.

YIKES. The prices on the parts is astonishing! I was thinking of making six or seven (five "live," one spare, one for myself) units. The cost looks prohibitive.

I guess I could put together something with 20' extension cords, using the plugs and receptacles as safety keys and maybe some kind of lamp and button in a chunk of PVC pipe with end caps.

* * *
Has anyone looked into what it would take to replace the incandescent bulb with a nice bright LED? What size resistor would be necessary?


Yeah some PVC pipe could make easy to build controllers... just need some lamp cords for leadouts, one male to plug into the power supply from the battery jumper pack or car battery clip whip, and a female plug for the launch ignitor extension cord to plug into going out to the pad. All you really need is a momentary push button switch. Drill end caps for the PVC pipe and do the wiring inside to the switch, install the switch in the pipe cap on one end and tie a knot in the cords for strain relief and run them out a hole drilled in the cap over the other end, before you install the electric plugs or wiring to the switch, either way. You could even incorporate LED indicators or just glue LED's into holes drilled in the pipe or cap and labeled for "power" and "arm" (battery connected and continuity, respectively) if you so chose...

Safety keys are the hard part... technically speaking the rule book says a safety key must be TOTALLY REMOVABLE to disable the circuit when it's not inserted, so a momentary switch won't suffice because it cannot be removed. A key switch or turn switch could be, but those get expensive and not easy to make on your own or cheap. Hence why the Estes controllers use a pair of close-fitting contacts attached inside the controller which are "bridged" by a steel "safety key" when it is inserted through a hole in the front face of the controller. You could do something similar with screws or something I suppose, with a hole on the front into which a copper launch key made from house wiring "Romex" wire could be inserted, but it might be problematic. I suppose that a momentary switch mounted INTERNALLY which could ONLY be activated by pressing in a "key" from the outside through a hole could technically work, since it would serve the same function and would "fail safe" (circuit normally open) when the switch is released. The key for that could basically be anything, plastic, wood, or metal, that would fit in the hole and depress the switch. Two flexible metal contacts pressed together by an inserted "key" would work as well-- just have to MAKE SURE they actually spring back apart to open the circuit when the key is "removed". That's why Estes uses the key to physically bridge a gap in the circuit-- spring pressure on the contacts only is necessary to make sure they connect electrically to the key itself when inserted, but otherwise the contacts are completely spaced apart sufficiently to break the circuit unless the key is inserted. Estes started putting "O-rings" on their keys to act as a "spring" to REQUIRE the person launching to push the key in physically to complete the circuit for launch-- if they release pressure, the O-ring unsqueezes and pulls the key up enough to break the circuit between contacts...

Later! OL J R
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