Multi Rocket Controller

Hello, I am new to this forum, but I'm not so new to model rockets, I have been building them for about 7 years. I have built many model kits, as well a scrounged parts to build cutom rockets. What I would like to do now is to get into building custom ground support equipment.

In a few months, my Boy Scout troop is going to be goin on a campout where we will be launching model rockets; and we decided that it would be cool if we could hold a competition to see who's rockets went highest, farthest from the pad etc, as well as drag races; to this, we would need a rocket controll that could launch multiple rockets at the same time.

Below are the 2 schematics that I have made as a crude representation of what the circuits will be like: (I adapted this from the info central multi launcher design)

The main panel:


The Sub Stations:


I gave a description of what I want to happen; and from my knowledge of electrical circuits, that should happen as I have deisgned the circuits. Are there any electrical geniuses out there that could help and tell me if this is right or give suggestions? Or does anyone know of any other multi launcher plans out there?

Thanks in advance.

Andrew
[email protected]

Welcome to the forum Andrew, firstly I'm sure you will find everyone here is friendly, helpful and willing to answer any questions you have. 2 points to remember "There is no such thing as a stupid question" and secondly "We Love Pictures."

I'm not an electrical genius so your schematics are just pretty pictures to me but I did find a link to a launch controller capable of launching 6 rockets. The article contains detailed instructions on how to build the controller, list of parts etc. etc.

6 Pad Launch Controller

If that doesn't help I'm sure someone on the forums will be able to look at your schematics or suggest another controller.

Good Luck and keep posting.

That is your idea of a crude drawing?

It looks pretty professional to me and I work with that stuff all the time!

I would suggest you work out a way of checking "continuity" to the igniter once it is hooked up. Just to avoid dissapointment when the launch button is pushed.

On your schematic I would change your letter designation a little just to make troubleshooting easier, (you can tell I'm a repair guy!)

My suggestion:
R1-2 to R1-C
R2-4 to R2-C
R3-2 to R3-C
R4-2 to R4-C
R5-4 to R5-C

Where "C" is the "-" (minus) or common...just me!

sandman

Trmbne2000 - welcome to the forum. One of our resident electrical/electronic geniuses is Carl Tulanko. Carl designed and built a MultiPad Launch Controller for me that handles 4 pads. It has continuity checking and many other useful features. I'm sure that when Carl has a minute he'll chime in here with some suggestions / tips / info (schematics, diagrams, etc etc).

Oh, and btw... Sandman is also a very multi-talented individual as well, so between he and Carl I'm pretty sure you'll get all the info that you need - not to mention the many other forum members - lots of talent here.

- Ken

Andrew,

First, I want to Welcome you to the forum...I hope you have a great time here and enjoy the friendships we have built through one common purpose, the discussion of Rocketry!!!

As far as your design goes, I must concure that it was indeed well drawn, but there are a few problems whioch can be easily worked out.

Her is your schematic that I have re-drawn, on the pad control side...to what I feel will work for what you wanted to do; I will cover the changes I made-

<img src="reviews/electronic.gif">

First, I started out by using a single, 12 volt car battery for power, as indicated by the move of the battery to the bottom and new rating of 12 volts. You can run extension cords to a 4 or 6-way power strip, then hook the strip up to the battery with aligator clips. This is an easy way to distribute power, it's cheap, it allows you to run off one power source instead of 5 batteries, AND since it is 12 volts, you can use it on Medium power Aerotech D-G motors or even High Power rockets, so your future expansion is there.

The second change was two-fold.

I moved your "Red Fire" LED into a circuit used for checking continuity. Before the rocketeer leaves the pad, they press the momentary "Test" button and if the ignitor is hooked up, the LED will light. Make sure you get an LED rated around 20ma...or better yet, use a buzzer from radio shack that only draws 7ma so you can HEAR the continuity test, but it will not draw enough to light the ignitor.

The second part consists of the REMOVAL of the previously mentioned "Red Fire" LED. They way you had it wired, the Ignitor would have never fired, because the LED would act as a resistor and only allow it's rated current, around 20ma, to flow, which is not enough to light the Ignitor. Now, when the button is pushed, up to 15 AMPS is applied to the ignitor, guaranteed to light.

Hope this helps you out...

Good luck and, again, Welcome to TRF!

Carl

Thanks for your advice everyone! What I meant by crude was that I just threw it together real quick, really the design on paper was more crude, it's just a bunch of scribbles.

Carl, would there be a way that, instead of having a test button and LED on each of the pad controls, there could be a group of LEDs on the main control panel, and when I threw a toggle switch, the LEDs that were recieving power would light up, thus indicating continuity of the circuit? I also like your external power idea. Would banana plugs and binding posts work to connect the battery to each of the sub stations?

Thanks for all of your help again!

Andrew
[email protected]

Andrew,

Yes, there is a way to see continuity on the master console...it requires you use all four wires of your phone cord for a single pad...so you would need 5 or 6 phone jacks/plugs for a 5 or 6 pad launcher. Here is the Schematic for a single section of a launcher I have designed and built. It has many safety features, plenty of alarms and flashing LED's, continuity testing, faulty relay testing, etc...

<img src="reviews/mplcsingle.jpg">

I recommend you build it for expandability...so use 8-Pin CAT5 Network Jacks instead of 4-Pin Phone Jacks. The reasoning being, redundancy and expandability...it takes four wires to run each pad...so, up to a distance of around 100 feet, you can still use 4-Pin Flat Phone Wire with Plugs, as they fit inside the CAT5 Jacks. For longer runs, use real CAT5 8-conductor wire and the circuit design runs two wires in parallel, for a combination of 4 pairs. You still get the 4 (pairs) wires for control to the pad box, but there is less loss and voltage drop since you have twice the copper running per line.

As far as banana plugs go, I designed them so 5 or 6' wires with aligator clips used banana plugs to each pad control box. However, for power, I still used Household extension cords because, for the price of one banana plug set, wires, and binding posts...you could have bought a plastic 4-outlet box, a faceplate, Two 2-socket electrical Sockets and 4 extension cords.....

Also, look at Radio Shack Online...they have some cool boxes; and had 30amp Auto Relays for about $2.99ea....pretty cheap! Let me know if you want more Schematics or socket Pin-Outs...I have it all documented. Here is a Pic of the Multipad I built for Ken:

<img src="reviews/mplc.jpg">

Enjoy,

Carl

Thanks again Carl,

I have made a few adjustments to my plans as per your advice and I added a few aspects from your schematic that I liked, and I think that I have just one more question. What kind and power rating of relays do you suggest I use in the sub panels? I think that they should be Single Pole Single Throw, but I'm not sure. I have decided to go with the CAT5 jacks like you suggested. Yeah, I have been looking around at the Radio Shack site for a few days looking over the selection, and I have picked out a few of the components already.

Thanks again.

Andrew
[email protected]