Building my launch control system

[RodRocket]

I have found several ideas for a launch control system and I am closely following the ideas from here https://principialabs.com/electronic-launch-control-system/

I am not going quite as fancy with the keyed switch. Mine will be a simple 1/4 mono audio jack and the key will be a short bit of 1/4 metal. No key, no power.

Relay box will be same as on the above site and the control box will have two momentary push button switches and two LED's.

The way I would like my system to work is you first check at the relay box for a welded relay by pushing a SPDT momentary button. No sound from a buzzer means ok to hook up igniter to relay box.

Next at the remote control, the key is inserted, red LED will glow, push and hold first button and green LED will glow if continuity is good, also buzzer will sound, then red button can be pushed to launch.

This system will take both hands to launch. And has the added safety at the relay box to check for a welded relay.

I have the basic layout of the parts done, still have to locate a few electronic bits and get the remote cord and jacks done. But it is coming along great.

Can't wait to try it out, may have some local farm land that I can use for launches and decided to get started building the launch system and pad.

Launch pad will be a metal saw horse with one or two rods and pads. I may have come across a nice source for stainless rod, a whip c/b antenna. I have to double check the whip diameter to the launch lugs. If not I will just get steel in the proper sizes to fit.

This has been great fun learning about this hobby. Just wish I had started 30 years ago.

See ya,
Rod

 

[kruland]

Rod,

This is the controller I came up with the help of John Brohm.

It has many of the features you are looking for - the switch on the relay completely turns off the controller and tests for a welded relay. It has a continuity check at the relay and also at the controller.

I built it without sw-2 in the controller. Now the piezio beeps whenever the safety pin (sw-1) is in. It doesn't depend on continuity with the ignitor. This is a big incentive to pull the safety switch after launch (because it's very annoying).

The biggest problem is it requires 4 lines between the controller and relay. If you want the piezio tied to continuity you can get by with 3 lines and then use extension cords and standard outlets for the interconnection.

Kevin

View attachment Kruland Controller (Rev 2).pdf

 

[[POW]Eagle159]

I sadly made mine with 30' of speaker wire and a momentary switch...and clip wipes for 2 at the end.

I had all the stuff so it was Free and good to go for a 12v lawn mower battery.

Works prefect for at my little field.

 

[RodRocket]

I have the control and relay boxes working like I want. Instead of having to push a button to test for a welded relay, if the relay is closed, the buzzer is on, no matter what. So there is instant warning of trouble.

Hook up the relay box to 12v.
Hook up igniter, green light is on at relay box and at control box.
At control box, insert key, red light comes on.
Push and hold first black button, buzzer warns of ready to launch.
Push red fire button, rocket launches.

Now I need to work on the pads.

Has anyone tried to use the rod sections from a gun cleaning kit? They can be had in different diameters for the different calibers. They are threaded for tear down. And they are smooth when assembled. They can be found cheaply enough and would make transporting the pad much easier. Thinking I would actually make a single pad and just change rods when I needed if these rods would work.

Just tossing ideas out there.

See ya,
Rod

 

[kruland]

Rod,

I tried to find the schematics on that site but couldn't find them. Do you have some you want to share?

Thanks

Kevin

 

[RodRocket]

I used diagrams at a different link at the bottom of the page, there are also diagrams in the center of page. The CAD looking drawings.

I found the parts at Radio Shack and Lowes. Lowes had the phone cord and jacks that could be modified to work. I got the compact surface mount jacks and cut and filed the jack and matching holes in boxes. Then epoxied them into their boxes.

Project boxes and electronic parts were at Radio Shack.

I followed a couple different diagrams, and after several attempts at the different parts of the circuits, just basically started over and figured out each circuit on it's own.

The continuity circuit really gave me fits, but after I used the 12v LED 276-0084 and 0085 for indicator lights, circuits came to life.

I don't have any added resistors. I guess the built in resistors in the 12v LED indicators are doing that job.

After several test fires with Estes igniters, it should be a safe and reliable set up.

It helps to have different colored wires to identify each circuit as you build it. And test often. I got the actual firing circuits working first, then added each of the other indicator circuits to those.

I will get some pics later after I clean up some details and find or make some button and switch tags.

See ya,
Rod

 

[skybuster]

This looks like it could be a fun winter project, and one that I could use for clusters when I finally make one. I was on the website looking at the LC-3. I have a few questions. Does anyone have instructions on how to build it? Also, could it ignite a cluster of E's or even F's?

Thanks

 

[RodRocket]

Scored two 1/4 inch drill chucks at The Yard Store in Wichita, Ks over the weekend. They didn't have any material for launch rod. I did bring home a six foot piece of hard aluminum tubing that will fit the larger lugs on the Mega Mosquito and such but I'm worried it might be too flexy.

The launch system sends a full 12v to the igniter so I would believe it could handle everything you could throw at it. Only limits would be the cable size between battery and igniter. But make sure your relay can handle the amps. Wondered if maybe a car starter relay could be used if you really needed igniter amps.

skybuster, I followed the drawings found on the site. And got everything working one circuit at a time.

 

[skybuster]

Scored two 1/4 inch drill chucks at The Yard Store in Wichita, Ks over the weekend. They didn't have any material for launch rod. I did bring home a six foot piece of hard aluminum tubing that will fit the larger lugs on the Mega Mosquito and such but I'm worried it might be too flexy.

The launch system sends a full 12v to the igniter so I would believe it could handle everything you could throw at it. Only limits would be the cable size between battery and igniter. But make sure your relay can handle the amps. Wondered if maybe a car starter relay could be used if you really needed igniter amps.

skybuster, I followed the drawings found on the site. And got everything working one circuit at a time.

Cool, this looks like a great project to learn how circuits work after working with them "theoretically" in my physics class last year.

 

[Barracuda]

Here's mine,1/8"mini plug phono jack key is pc. of 1/8 rod cut,rca jacks for batt.and igniter hook up,arm sw. is illuminated when engaged.All was rat shack parts.I even did the paint job

 

[skybuster]

Here's mine,1/8"mini plug phono jack key is pc. of 1/8 rod cut,rca jacks for batt.and igniter hook up,arm sw. is illuminated when engaged.All was rat shack parts.I even did the paint job

Awesome!