AlnessW
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- Oct 6, 2013
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Been meaning to do a write-up on this for a little while now, plus a few club members have been inquiring...
Background
One of my objectives for an "in-season project" this year was to build some better personal launch equipment. First up was the tower, which has since worked wonders. The other thing I wanted to build was a single-pad personal launch controller. I wanted something more robust than a glorifed-Estes Electron Beam controller, which I had built many years ago and is what I was using before. I also took a look at a wireless system, Wilson F/X, (no, not me, a different Wilson) but that would have cost upwards of $500. Way more than I wanted to spend, so I opted to build my own wired system.
I was very happy with the results! My system consists of a controller, wire reel, pad box, and battery.
Construction and Photos
Pad Box
Here we have the pad box, which goes out at the "rocket end" of the equation. Under the blue cover is an on/off toggle switch, as well as a power indicator LED. The wires on the left have red and black battery clips which connect to the pad battery. Said battery is a 12V lawnmower battery which I got from O'Reilly Auto Parts. The wires coming out the front go to the rocket (alligator clips), and the extension cord out the right side plugs into the wire reel.
Wire Reel
This was the easy part - a 500' reel of wire made up of 2 x 250' reels of lamp cord, spliced in the middle. (Solder/heat shrink tube.) On each end of the wire is an extension cord plug.
Controller
On the controller end we have not 1, but 2 momentary switches. (The push-button and the toggle switch.) To launch, plug the controller into the end of the wire, then push and hold BOTH buttons to fire.
How is everything wired? Well, take a look...
Since I'm certainly not an electrical engineer, I needed a little help from the folks at Surplus Gizmos in order to get the pad box to do what I wanted it to do. And here we have the result, nicely color-coded for your viewing pleasure. (Also so you can tell the wires apart...)
As you can see, I used 2 relays - one 6V and one 12V. Essentially the controller trips the small relay, which then trips the bigger relay. But the diagram can explain it better than I can - I hope...
The controller is much simpler. Yes, I did figure this one out on my own...
1 standard 9V battery to send current to the 5V relay at the pad box. Along that is where I installed the 2 "inline" momentary switches.
The system in action:
Here you can see the pad box, wire reel, battery, and clip leads all in place. I made the wires extra long so as to distance the components from the pad, and away from rocket exhaust/flying debris.
When launching a rocket, the steps are as follows:
You asked...continuity. NO, my system does NOT check continuity. The red LED at the pad box simply indicates whether the system is armed or not. To be perfectly honest - I really don't care that much. I always use my own homemade igniters which I check with a multimeter before use so I know they'll work anyways. If I really wanted to, I could add a continuity check at a later date, separate from the firing circuit.
Safety Features
Of course, the system is designed with some safety features, as well.
All the parts for this entire project I sourced from:
Overall, this was a really fun project - not too challenging and very affordable. I may build another one of these over the winter, just for giggles and so I can have 2 on hand. Heck, if there is interest, I may even start selling them...
Drawback - now that I have both my own pad AND controller, I never want to use club GSE again... :wink:
Enjoy!
Background
One of my objectives for an "in-season project" this year was to build some better personal launch equipment. First up was the tower, which has since worked wonders. The other thing I wanted to build was a single-pad personal launch controller. I wanted something more robust than a glorifed-Estes Electron Beam controller, which I had built many years ago and is what I was using before. I also took a look at a wireless system, Wilson F/X, (no, not me, a different Wilson) but that would have cost upwards of $500. Way more than I wanted to spend, so I opted to build my own wired system.
I was very happy with the results! My system consists of a controller, wire reel, pad box, and battery.
Construction and Photos
Pad Box
Here we have the pad box, which goes out at the "rocket end" of the equation. Under the blue cover is an on/off toggle switch, as well as a power indicator LED. The wires on the left have red and black battery clips which connect to the pad battery. Said battery is a 12V lawnmower battery which I got from O'Reilly Auto Parts. The wires coming out the front go to the rocket (alligator clips), and the extension cord out the right side plugs into the wire reel.
Wire Reel
This was the easy part - a 500' reel of wire made up of 2 x 250' reels of lamp cord, spliced in the middle. (Solder/heat shrink tube.) On each end of the wire is an extension cord plug.
Controller
On the controller end we have not 1, but 2 momentary switches. (The push-button and the toggle switch.) To launch, plug the controller into the end of the wire, then push and hold BOTH buttons to fire.
How is everything wired? Well, take a look...
Since I'm certainly not an electrical engineer, I needed a little help from the folks at Surplus Gizmos in order to get the pad box to do what I wanted it to do. And here we have the result, nicely color-coded for your viewing pleasure. (Also so you can tell the wires apart...)
As you can see, I used 2 relays - one 6V and one 12V. Essentially the controller trips the small relay, which then trips the bigger relay. But the diagram can explain it better than I can - I hope...
The controller is much simpler. Yes, I did figure this one out on my own...
1 standard 9V battery to send current to the 5V relay at the pad box. Along that is where I installed the 2 "inline" momentary switches.
The system in action:
Here you can see the pad box, wire reel, battery, and clip leads all in place. I made the wires extra long so as to distance the components from the pad, and away from rocket exhaust/flying debris.
When launching a rocket, the steps are as follows:
- Place rocket on pad/arm altimeters, etc.
- Insert igniter.
- Connect igniter to launch system.
- Turn power switch at pad box ON.
- Retreat.
- When ready, and only when ready to launch, plug the controller into the end of the wire.
- Hold BOTH switches to launch.
- When launch is complete, unplug controller from wire.
You asked...continuity. NO, my system does NOT check continuity. The red LED at the pad box simply indicates whether the system is armed or not. To be perfectly honest - I really don't care that much. I always use my own homemade igniters which I check with a multimeter before use so I know they'll work anyways. If I really wanted to, I could add a continuity check at a later date, separate from the firing circuit.
Safety Features
Of course, the system is designed with some safety features, as well.
- The power switch at the pad box must be powered ON in order to launch. The rocket will not launch if it is powered OFF.
- The controller is plugged in to the wire ONLY when ready to launch. It is impossible to accidentally send current to the relay when the controller is unplugged.
- BOTH momentary switches at the controller must be held in order to launch.
All the parts for this entire project I sourced from:
- Home Depot
- O'Reilly Auto Parts
- www.digikey.com
- Surplus Gizmos, a local electronics shop.
Overall, this was a really fun project - not too challenging and very affordable. I may build another one of these over the winter, just for giggles and so I can have 2 on hand. Heck, if there is interest, I may even start selling them...
Drawback - now that I have both my own pad AND controller, I never want to use club GSE again... :wink:
Enjoy!