Relay launch controller pads

Discussion in 'Ground Support' started by rocketdoctor99, Dec 16, 2019.

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  1. Dec 16, 2019 #1

    rocketdoctor99

    rocketdoctor99

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    I want to upgrade my current launch controller to use relays. Ive seen relay controller as launches where they have continuity lights at remote pads, i would like a design to have this. Ive seen on this and other forums/websites lots of diagrams but is there anywhere I can get more information such as pictures of control boxes, wire gauges to use, recommended batteries for pads and controllers and how to order each part?
     
  2. Dec 16, 2019 #2

    Voyager1

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    You will find many examples of launch control units by just googling “rocket launch controllers”.

    Do you want continuity to be displayed just at the pad box, or at the controller as well? Both places would be the ideal choice. How many channels are you considering?

    Our group uses 28 AWG 9-core shielded cable for the low current field cable between the the controller and pad boxes. This has been fine out to 100 metres. For high current ignition circuits at the pad you would use around 14-18 AWG.

    The controller can use a 2S or 3S LiPo up to 1Ah; for the pad box we use 12V/7Ah SLA battery, but some groups use 12V car batteries!
     
  3. Dec 16, 2019 #3

    Voyager1

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    Last edited: Dec 17, 2019
  4. Dec 17, 2019 #4

    mikebpd221

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    I made my personal launch controller system incorporating a 12v relay on the launch circuit. The system uses two boxes, one for control inputs and the second at the pad. Continuity is by an LED indicator at the pad with a pushbutton to check for a fused relay (prevents accidental ignitions). This forum and Google are your friends when it comes to research and I found using a circuit layout program (digikey.com) really helped organize my thoughts on how to get what I wanted to wire out in a way that worked. I'm no expert at this, so other members may look at the pictures of what I did and tell you to steer clear, but I'm on a couple dozen launches with it and no pad related failures yet. The basics on the system are: pad box contains two batteries. One controls the low current side, continuity circuit and warning system. This connects via Cat 5 cable to the control box. The launch command hits the relay and a second battery powers the ignition circuit. Certainly more complicated than it needed to be, but it works and was a good learning experience to build.
     

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  5. Dec 17, 2019 #5

    rocketdoctor99

    rocketdoctor99

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    Thanks I currently have a 10 pad control box that i use for 4H rocket launches. The controller is 15 feet and I run a car battery with 14 gauge wires to pad but the connector wires are maybe 18gauge. My launches are intermittent and I am suspecting the pad wires. instead of rewiring I thought I just upgrade to Relays, also would allow me to run longer control lines.
     
  6. Jan 25, 2020 #6

    Glasspack

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    Rocket Doctor,

    I ended up so frustrated with my old controllers I decided to make my own Launch Controller as well. Here is the one I made. It controls four pads for individual launch or a four pad drag race depending on the "ARM" configuration. Happy to share ………. IMG_3620.JPG IMG_3622.JPG IMG_3629.JPG
     

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  7. Jan 25, 2020 #7

    Glasspack

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    Of course I have the schematics and test videos of it as well
     
  8. Jan 26, 2020 #8

    Voyager1

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    Nice work! I'd like to know what relay modules you used. Are they off-the-shelf or your design?
     
  9. Jan 27, 2020 #9

    Glasspack

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    Most of the parts are from Sparkfun.Com
    The relay kits are nice.......however I used a different relay than the kit came with. All other kit parts were used, but I wanted a relay with a higher amperage rating.... let me see if I can find them again........
     
  10. Jan 27, 2020 #10

    Glasspack

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  11. Jan 27, 2020 #11

    Voyager1

    Voyager1

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    Ordered! Thank you, much appreciated. I’ve purchased many things from Sparkfun, but I’ve never seen these relay modules on the site. Much cheaper and higher rated than the ones I was planning to use.
     

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