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Need Help Building Simple Launch Controller

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Dale

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hello all. first of all I suck at wiring complicated stuff.:bangpan: back in the early 70's when I was around 13 or 14,my brother and I made[don't remember how] a homemade controller using a small box,door bell button and those old 1 and 1/2 volt batteries.we also used small gauge wire with small alligator clips attached.anyway,it worked.now I'm trying again using 7X7 cigar box.this time with 4 AA's.this where I'm stuck.oh yeah,I'm not using any arming switch/light.don't know how.first I have red and black wire coming from DB button.I get confused from there,lol.what ever I try,the batteries get warm which can't be good.:facepalm:I would be greatful for any help.I do have a estes controller to use.this one,I hope will be a back up.
 

tomsteve

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im thinkin if ya open up the back of the estes controller, you can get an idea of how to wire your new one.
an arming light/switch really isn't that difficult to figure out. yes, wiring schematics are a bugger to read- I can tell ya what ground is! :). ooo, theres a battery! LOLOL
but what youre lookin at is pretty simple.
one wire from the battery should go straight to the ignitor. the other wire should go from the battery then to one terminal on the button. then another wire from the other terminal on the button to the ignitor.
 

wydah

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Hello Dale,

I built a nice launch pad way back in 2011 but have been away from the hobby for a number of years and hope to get back into it again soon. If you're just interested in the very very basic controller I've included a sketch below. Note that you can skip the continuity-check bulb, and the "Launch Pushbutton" will be your doorbell. The "Spring-return Keyswitch" is a second switch used for safety...so you can't accidentally launch if you bump the doorbell switch. You would need to hold that switch down AND press the doorbell to launch.


Well hope this helps you. :)

Be safe!

rocketcontroller.png
 

Dale

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thanks guys for the help.:cool:
 

samb

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I always go back to the place I learned about 'um, Estes. https://www2.estesrockets.com/pdf/2811_Estes_Model_Rocket_Launch_Systems.pdf

Estes_Model_Rocket_Launch_circuit.png


Another thing to consider with home built controllers is the safety lockout. It's the metal pin used in Estes controllers. The safety code used by Tripoli and NAR clubs specifies a removable safety interlock device in series with the launch switch, irrespective of the number of switches and buttons you put in there.


https://www.tripoli.org/Portals/1/Documents/Safety Code/SLP - May 2016.pdf

https://www.nar.org/safety-information/model-rocket-safety-code/
 

Dale

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I do have a on/off switch used in household lighting I could use for safety.
 

samb

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I do have a on/off switch used in household lighting I could use for safety.
Yeah, well, no I wouldn't add another switch to the circuit in wydah's post. Just adds construction complexity and the additional step to arm the circuit makes a small contribution to safety but doesn't match the idea of the safety interlock. IDK I thought the Estes document explained it way better than I could. For the most part the NAR/Tripoli safety code section on launch controllers was written in the 1960's. Maybe switches and buttons were much more unreliable then and a physically removable piece of the firing circuit was the only way to be positive that electrons would not flow, regardless of switch settings. Plus in a club launch environment with many fingers you want to make the controller immune to stray button pushers and switch flippers. Just test your system to ensure it lights the igniter when you want it to and doesn't light it any other time and you'll be good to go.
 

Rex R

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I have seen an Estes controller suffer from a stuck launch button(early 70s, a grain of sand caused it). not hard to wire an interlock, two ends of an extension cord (male & female plugs) would work.
Rex
 

samb

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Found a picture of the electric plug Rex mentioned used as a safety interlock. The old Centuri Cub Scout Activity pack.

centuri cub scout launcher.png

https://www.oldrocketplans.com/centuri/cen1654/cen1654.pdf

Mash all the buttons and flip all the switches you want, the juice won't flow until the plug is inserted. Shorted phono plugs, locking key switches, some variation of the Estes pin all perform the same function. Easy insurance against unintended ignition I think.
 

Dale

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I agree with samb.don't think I need the safety switch.at the moment,I'm not a member of NAR [didn't renew] and have no plans on doing any events.
 

samb

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I agree with samb.don't think I need the safety switch.at the moment,I'm not a member of NAR [didn't renew] and have no plans on doing any events.
Piling on more switches doesn't buy you much. If I haven't been clear, what I'm trying to do is get you to see the value of one little ol' removable safety interlock ! :grin:

Good for everybody IMO.
 

Dale

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I get it.That config won't work with my controller because I'm using smaller gauge wire,but if I decide to build another one,I'll try that design.:cool:
 

UhClem

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I agree with samb.don't think I need the safety switch.at the moment,I'm not a member of NAR [didn't renew] and have no plans on doing any events.
Will you be launching in a jurisdiction that has adopted NFPA 1122? If so, then you are required by code/law to follow it even if you aren't a member of NAR.

A quick search shows that the state of Virginia has indeed adopted such a code.
 

Dale

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ok,I tried the ideas of tomsteve and wydah.today I wired the controller with a ignigter and nothing happened.my wiring is not the greatest but still should have worked.
 

Dale

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David,I recently joined NOVAAR so I guess I'm covered.
 

tomsteve

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if you have a volt meter, check the DB button to make sure youre getting current though that- set it on ohms and put a probe on both leads on the DB and push the button.
how long are your leads from the box to the ignitor? with the setup youre workin on, ya don't want them very long-id say no longer than what an estes controller leads are. 15 feet?
im thinkin a picture or 2 of what ya have may help us help you
 

Dale

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I think I know the problem.one of the controller leads going to the button or battery the wire is black and could be fried.sorry can't post any pics at this time.I'll post again if I don't find solution.
 

Dale

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lol,wrong! ignighter was bad.tried another and it worked.:wink: now paint it.
 
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