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HPR Advanced Launch Control System

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Austin

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I have had several inquiries in the past, along with some more recent regarding the launch system I use for my rockets, so I decided to finally stop procrastinating and write something on them.

Several years ago I decided to build my first launch controller and hit the web browsing for some ideas. I visited many sites and saw all different types of launchers from the more complex ones listed at ROL to simple ones on user sites. None of them though fit with what I wanted in a launch controller. My first launcher was similar to the one from ROL and even included the dual relays, but I changed much of the internal wiring to meet my needs. Since those early days, my HPR launch system has been a work-in-progress, changing over the years, and becoming more modular, resulting in my most current system. In addition, the design has been simplified, providing a more efficient and cost effective solution to my needs.

The first controller did incorporate dual relays and used a 5-pin Din plug for a connection. This unit was very reliable and is still in service today. Next came my first attempt at modular design and this design is still used for my systems today. This was the MPLC or Multi Pad Launch Controller I built for my very good friend Ken Parker. Most of the circuitry is still in use today, along with its modular design. One of my latest controllers was the MicroMax Mega Pad and incorporates all the latest features now used. I saw the need for several changes to be made over the years, which resulted in the Mega Pad, my most current HPR Launch System. This system contains two main components, a Launch Controller and a Pad Unit.

• 12 Volt DC design, required for mid to high powered single-use or RMS rocket motors.
• Runs off a standard 12VDC automotive battery.
• Heavy Duty cabling throughout for minimum current loss.
• Extended cable length allowing control 100+ feet distance from pad.
• Meets or exceeds NAR and Tivoli distance requirements.
• Additional extendibility for Level 2 and Level 3 model launches.
• Built in line loss inhibitor parallels twin wires internally for distances over 100’.
• Custom length 8 conductor cables when exceeding 100’ distance (Optional).
• Allows over 15’ of separation between launch pads.
• Pad separation can be increased by using heavy-duty standard AC extension cords.

The Pad Unit contains a 30amp automotive relay capable handling the power of many different launch configurations. To date, the Pad Units have fired four igniters at a time in parallel (the MPLC) and has fired four HPR igniters paralleled off just one Pad Unit. Also, a single Pad Unit was brought in at a launch when the club system couldn’t handle the task of firing 14 Este’s igniters in parallel. This really cool cluster launch went without a hitch when the system ignited all fourteen motors…and this was all done from the MicroMax Mega Pad, which incorporates my most current design.

Features of the Pad Unit include a DC Power Switch and green LED Power Indicator. There is a 30amp slow blow fuse in line with the power circuit and I have yet to blow a fuse at a launch. A piezo buzzer is used to check continuity with a pushbutton installed on the face of the Unit. The user can check continuity "at the pad" before he walks back to the table. Banana Plugs are used to connect the igniter cable from the Pad Unit to the Igniter. This “modular feature” allows you to build many different types of cables to suit your needs. I have a set with large alligator clips, a set with small alligator clips, a set with an Aerotech Igniter Clip and a set with raw ends, for clip whips and cluster connections.

Other Pad Unit features include a “relay short” test button, found on the top side of the unit. This button tests for a relay that may have welded contacts and a red LED indicator on top of the Unit lights if the relay is shorted. The relay can be easily replaced if there is a problem. This button is also multifunction though, depending on what is connected or if the hand controller is wired…a nice feature if you ever had to troubleshoot the unit. Another “modular feature” is the Battery Power Connector for the Pad Unit. A 2-conductor plug is used and allows you to use a power cable with battery alligator clips, or a cable with a cigarette lighter socket. You could also have a power cable with an AC power plug as used on the MPLC and capable of being lengthened using a standard extension cord, or a cable with raw wires or spades for special connections.

Connection to the Launch Controller is made via a CAT-5 socket on the Pad Unit. The socket is wired so that the positive and negative 12 volt connections are at each end of the plug, isolating them from shorting with each other. The CAT-5 Socket is an eight-conductor socket, but launches up to 100’ can be achieved by using only the four center pins of the socket. For this reason, a simple flat telephone cord with RJ11 plugs at each end is all it takes to connect the Pad Unit to the Launch Controller. For distances over 100’, standard CAT-5 Networking Cable is used to connect the two devices. The CAT-5 uses all eight pins, “doubling up” and paralleling wire pairs into four pairs to help decrease voltage drop you would get with the longer cables.

The Launch Controller for the single launcher is a hand controller, which is small enough for a child to use, yet easily fits an adult’s hand. It is powered by the Pad Unit, which means no additional batteries are required and has a separate Power Switch on the side that is easily activated by the user’s thumb. When active, a green “Power” LED illuminates, indicating power is present and the internal circuitry is enabled. Also, if continuity is present, a “Continuity” yellow LED lights and the Pad Unit buzzer is heard. A high quality detent keyswitch is turned to “Arm” the pads, and the red “Arm LED” begins flashing indicating a ready-to-fire state. The “Fire” button activates the relay resulting in a launch. If an igniter burns out, the audible continuity will stop…this is a convenient feature in case you have a misfire and lets you know the condition of the igniter.

This system to date has been very reliable for me and others and has stood up to many launches. As stated, many changes have been made over the years, but it is nice to know that the “Modular Design” allows the same hand controller for the MegaPad or HPR controller to be mixed with the multipad launcher and vice versa. This modular design also comes in to play by allowing for a variety of cabling options, both at the pad and at the battery. All this in mind, the unit is still simple and can be built by anyone with some basic knowledge and soldering skills. Moreover, it can be used on a variety of rockets from MicroMax to HPR Clusters.

I have posted some pics showing the development of this Launch System over the years and I hope they better illustrate what I have stated. All the parts except for the keyswitch cane be purchased at Radio Shack and I have included a parts list for your convenience. All labels for the boxes were designed by myself and printed on Avery paper, then clear coated. I really enjoyed designing and building these units over the years as I guess it is in my blood. I started playing with electronics when I was ten, got my first Amateur Radio License when I was 16; it's been over 32 years since then and I still enjoy Ham Radio and electronics…it a lot of fun! :)

If you have questions, feel free to send me an email and I will help as much as possible.

Launcher Pics - http://www.rocketryforum.com/ctulanko/album/index.php?dir=launcher

Parts List - http://www.rocketryforum.com/reviews/partslist.xls


Thanks,

Carl
 

n3tjm

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Cool schematic... you know.... I think I might built this one... my really launcher needs a major overhaul anyway.... And I like the Continuity check on the launcher itself :)
 

rstaff3

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Very professional looking, as we'd expect from you Carl :)
 

Cajunman06

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That is sharp! Something very similar to what I was dreaming of building. I had a few questions regarding the circuitry I was going to use, so I'll study your schematic before asking.

One question I do have is where did you get that "box" for the multipad controller?

C
 

Stones

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Carl...
As usual, another class act of description and pics. It's one thing to develop ideas, another to be able to make it understandable for the masses. You achieve both those goals.
One question, could you possibly post your parts list in a .txt format? Much obliged.
 

KenParker

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Stones - I tried to convert Carl's file to .txt for you. Hope this works for you.
 

Stones

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Originally posted by KenParker
Stones - I tried to convert Carl's file to .txt for you. Hope this works for you.
Works like a charm Ken. Tnx very much. I tried a converter prg but, it said I needed Excel in order to do the conversion....make any sense? Tnx again. ;)
 
A

Austin

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Thanks guys,

I hoped you would find the info useful. Cajunman, the box used for the MPLC was purchased from Radio Shack online several years ago, but is no longer available. The same goes for the DPST switches it used to select pads; they too are no longer available. I am sure a substitue could be found, but it appears Ken will have the one-of-a-kind Mulit Pad Launcher.

Stones, here is a parts list in text format:

Parts List Document - http://www.rocketryforum.com/reviews/partlist.doc


Carl
 

Stones

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Tnx Carl. I'm looking forward to building your system for the rail pad launcher I built awhile back ago. I've always wanted to get the battery at the pad with a relay and I like the idea of using one power source for the controller/pad. Tnx again.
 

shockwaveriderz

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Carl:
I don't suppose you ever considered making and selling soem of these to people? I would be in the market for a individual launch controller if the price was reasonable.....
 
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