4 pad Launch controller

[Devin Batten]

I have built a single pad launch controller capable of LPR and MPR launches confirmed up to a G76. As a rather transient individual I like to have a capability to launch up to 4 pads at a time to help out at launches I find myself at. I have the pads built and ready. Just need a launch controller to match. Ive acquired a nifty James Bond looking case at no cost to me and have plenty of components left over from my previous built. Before the Aesthetic crowd chimes in I'm young and go for function over form.

 

[Devin Batten]

Expected outcome; a functional launch controller capable of launching 1 MPR rocket or up to 4 LPR at a time for the drag races. And running off of a 11v LiPo battery.

 

[Devin Batten]

Started off cutting out a piece of 1/4" plywood to serve as a base. And laid down the electronics in a classic pattern. The electronics include a Key switch, 4 toggle switches with covers, 4 red led, 4 disconnetable leads for the pad outputs, 1 buzzer, and of course a nice red button for launch.

 

[Devin Batten]

Holes drilled into board and then covered in a CF vinyl wrap. Components then placed in the board. Easy part done next is the wiring.

 

[Voyager1]

You might like to add a fuse or resettable circuit breaker. I suggest a slowblow 10 A between the battery and the key switch. Also, are you planning to include a continuity LED on each ignition circuit. Is that what your LEDs are for, or are they just select/ignition indicators?

 

[OverTheTop]

You might like to add a fuse or resettable circuit breaker. I suggest a slowblow 10 A between the battery and the key switch.

Great idea. Also have a packet of spare fuses taped inside the lid for when you blow some in the field.

 

[Devin Batten]

You might like to add a fuse or resettable circuit breaker. I suggest a slowblow 10 A between the battery and the key switch. Also, are you planning to include a continuity LED on each ignition circuit. Is that what your LEDs are for, or are they just select/ignition indicators?

Great idea for the fuse, and the LEDs are for both, along with the buzzer for continuity since sometimes you cant see the LEDs very well in direct sunlight.

 

[Voyager1]

I use these circuit breakers in my launch controllers.
https://www.ebay.com.au/itm/EATON-H...776425?hash=item1e7bf694e9:g:1gkAAOSw3h1ZWExr

 

[Rocks&Rockets]

Looks remarkably like one I built. I used a piece of micarta for the top. 4 standoffs hold it all in a small black box from the cheap tool store. (not a Halliburton or Pelican but not too bad). Toggles are DPDT - One side momentary for the continuity test and other side latches down to arm the designated pad. LEDs are 12v superbright green easily visible in daylight and safe for continuity test. Key must be at "start" position and red push button to depressed to launch. I used wire I had on hand- 200' 4 conductor 18ga. and 2/18. Thats why there are 2 connectors out.

 

[Devin Batten]

Looks remarkably like one I built. I used a piece of micarta for the top.

What are you using for the cable to the pads?

 

[Ronz Rocketz]

With that much space, you gotta add simultaneous key switches and a number pad to insert the launch codes. Watch the opening to Wargames or the launch sequences in Crimson Tide for inspiration. Sorry, back to function over form...

 

[Rocks&Rockets]

I use a 200' roll of 4 conductor 18 ga to get to the launch pad. That gives me 3 pads and a common return. I have a second roll of 2 conductor 18 ga that is a little shorter for the 4th pad. I shop for leftovers at our second hand stores like Habitat. Have you priced 200 feet of new 6/18 wire ? Eeek! Cannon plugs and bayonet connectors are not cheap either but usable ones can sometimes be found at surplus stores.

 

[Devin Batten]

With that much space, you gotta add simultaneous key switches and a number pad to insert the launch codes.

That would be an awesome addition. My skills are already being pushed just outside of where they're at giving me the room to learn. I was already planning on upgrading it eventually to a look like a "football". Just got to build up my skills.

 

[Ronz Rocketz]

That would be an awesome addition. My skills are already being pushed just outside of where they're at giving me the room to learn. I was already planning on upgrading it eventually to a look like a "football". Just got to build up my skills.

Just be sure to leave space for upgrades...

 

[UhClem]

I use a 200' roll of 4 conductor 18 ga to get to the launch pad.

The good news is that this will limit the stress on your switching components. The bad news is that it will limit igniter current. A lot.

 

[Voyager1]

The good news is that this will limit the stress on your switching components. The bad news is that it will limit igniter current. A lot.

Yep! 200' of 18 AWG will have as much resistance as the typical igniter. You'll lose 50% of your ignition current. I'll use 16 AWG speaker cable over 100', but anything over that I would use a relay-based pad and controller , particularly for a multi-channel system.

 

[Rocks&Rockets]

200' of 18 AWG will have as much resistance as the typical igniter. You'll lose 50% of your ignition current

True... each line on the 200' spool has been measured at 2.7 ohms. Tested and tried using Estes, Firstfire and other Igniters without fail. (dont use copperheads). The best igniters for my system are rated all-fire at 300mA. All 4 channels fire simultaneously. But I'm also using a 12v, 10amp Battery.

 

[Voyager1]

Copperheads! Don’t get me started on them!
That can be another thread.