Wireless Launch Control

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I did order it. It's tool milled and engraved, not laser. I was so tired of making these panels by hand.
 
This thread is great. I am continually amazed by the knowledge of the members here. I'm a smart guy, but I'm definitely one of the dumb ones around here. :)
 
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Yep, I thought about using a resettable fuse type device – like a polyswitch. The specs on these devices are confusing at best. In a nut shell, it was the response time is that bothered me. 10+ seconds is a heck of a long time to have a direct short running through your relays. I was not sure that the device would trigger quick enough to protect the relays. I’m glad you were able to get them to work, but I was not sure I could get one of these to function as intended.
The alternative to not using a thermal breaker is to have the wiring melt with 100A from a car battery. It is a simple series component without the complexity (and failure modes) of an active circuit. Being a thermal device, it trips from a high current in less than a second. A 10A thermal breaker will handle 30A without tripping during the time it take to ignite an igniter.

I've used many of the surface-mount autoreset breakers in commercial designs for various applications over the years. They help pass fail-safe requirements for UL and other regs if sized appropriately.
 
Thanks jsdemar, that certainly makes a lot of sense. The 30 amp Polyswitch units did not appear to be fast enough acting (after pouring though lots of complex graphs in the spec sheets). I'm glad that you did the work and figured out a suitable part. If possible could you recommend a specific part. I would love to update my club's existing system with this type of device. This seems like a no-brainer for extending the life of a launch box. I used high temp silicone wire for the high current wiring inside the box, but I would like to interrupt the current flow during extreme conditions.

Dan
 
Looks great. Is this unit set up for selecting 3 separate 8-pad field boxes? Does this correlate to heartbeat A, B and C? If so, how does one select between each bank of pads?

Dan

No this one is just 8 remote pads. Typically two nodes or clusters of 4 pads each. Meaning 2 field boxes. Hence the two master arm switches.

The LCO master control module does have a 3 bit binary input that I call 'control mode'. It theoretically could be used to point the controller to up to 8 groups of 8 pads. So that little panel could actually control up to 64 pads! But I haven't even started to think about how to provide that input. Maybe a rotary switch or something on the panel. Or a separate panel. Hopefully not too ugly.

The heartbeat LEDs are very important feedback sources. So is the sonalert. There are 5 microcontrollers in the 8 pad controller console. Two display controllers, two pad controllers, and the LCO master which is basically the wireless interface. The display controllers are mostly atonomous and don't have a heartbeat. The two panel controllers are heartbeat A and B, and the LCO master is C. I won't get into all the details here but if the pad controller loses synchronization with its field box, for example, it will beep the sonalert 3 times and then start flashing its heatbeat rapidly. Normal is a slow, steady heartbeat.
 
Time to marry the panel to the LCO enclosure. Another small build step.

The bezel has tabs and clips so the panel can be attached by screws. But for my custom panel I elected to not have those holes or screws. Instead we'll glue it.

Specifically I will use a bead of Liquid Nails all the way around the bezel. I've had great success with that glue in the past. Tough stuff.

Takes 24 hrs to cure though. So no more progess tonight.

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No time to work on this today, but here are the 'halves' ready to be wired together. Power, a few LEDs, and few busses. That's all. Plus the programmer interface which doesn't count. Power is actually the most complicated since we have battery charging plus internal and external power to deal with.

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A bit of progress today. The DC supply wiring is always something of a rats nest. The rear panel shows power and source switches, and the charger/ext power jack. The R/C batteries need their mating Tamiya connectors.

I wired up the voltage regulator for the LCO Master module. I don't like the way that looks but at least it's out of the way.

The last photo is all the DC wiring completed. Mostly. It all kind of busses together there on the far right. Out of the way.

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A few more. First the power and heartbeat LEDs are connected. And in the second photo the master arm LEDs and switches.

I really like these small IDC (insulation displacement) connectors. I still have to solder short wires onto the LEDs and switches and such. But at the PCB connector end I basically use a punchdown tool. Very easy and saves time.

Previously I would tin a wire, solder a pin onto the wire, fold down tabs to hold the wire, then insert into a housing. That system was more expensive too.

Just one more buss to run. For the launch button and sonalert. Then we're done. Almost.

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Last wiring pix, promise. Last two busses done. One from the launch button picks up a sonalert at the first module. Then on from there. The other is the inter-circuit communication buss. Two white wires, board to board. At the tail is is the sonalert. Glued in place and connected.

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Just one more. The D15 is for the ICSP or in-circuit serial programming interface. Of the 5 MCUs in this panel 3 can be programmed via this connector. On a production box this connector wouldn't even be there. But on my box it is. Lots of wires.

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Oops. Problem.

One of the functional tests is to turn on the master arm and pad select switches and see the results on the LEDs. With this configuration it's about the first time the pad control module can be tested.

When I did the test on the first pad group the LEDs started flickering and within seconds, smoke. Not good.

The circuits are proven so it must be a solder bridge, or a short somewhere. I was hoping it wasn't on the pad controller since it would be very hard to remove it to troubleshoot.

I put on my uber magnifying glasses and fortunately found the problem right away.

In the first photo if you look almost center but just to the left of the top of the 1N400x diode, you'll see a little solder blob. Pesky little things those are.

It wasn't even attached. In the second photo is the MCU that got fried, and just below, the tiny bit of solder blob that caused the problem.

I replaced the MCU with a freshly reprogrammed unit and all is well.

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Looks great, glad you found the solder blob. Powering up for this 1st time is always scary.

Dan
 
Especially is a solder it. It might just short through me. I definitely stick to DC power.

It is good that you only has to replace the one element.
 
Last thing to do inside the console to finish it up is install the wireless interface daughterboard and the wireless module. This of course is the 'secret sauce' that makes it wireless.

The first photo is the interface module and the wireless module. The wireless module needs to have the right firmware uploaded and a basic configuration put in place. That's done with the little USB interface board. Basically all I have to configure is enable AES encryption, set an encryption key, and set the baud rate to 115k. After the initial configuration the wireless module can actually be configured over-the-air too which is pretty cool.

The last photo shows it all installed. That's it. Even with programming it takes just about 2 minutes.

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Basically just picked it up over the years. I've always liked to build things.
 
Time to wrap up the LCO end of the system. The first photo is the completed LCO console still open and all laid out. This is the last we will see of the internals of this box. Except for the ICSP harness, it's not all that bad looking. Someday I'll dig up a picture of the first 8 pad system wired I made. What a nightmare in comparison.

Next the console is all buttoned up. Basically I just set the top in place over the bottom and secured it with a few machine screws. Piece of cake. And also two rear views. Actually I see I have the wrong hardware on the D connector, but I'll fix that later. For a basic charger I just used the one that came with one of the R/C batteries. I simply cut off the Tamiya connector and put on a 2.5mm power plug. Works great.

The antenna is the FCC approved 2.4gHz full wave articulated dipole. Five bucks. With just that type antenna I tested an earlier protoype out past 1500 feet. I was so far away I couldn't even see the pad. The launch was successful (an Alpha III).

Next, on to the field boxes (but not today).

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What does heartbeat A, B, C mean? I guess based upon what I read above that it is a check for a functioning Pad box A and B and the LCO box?
 
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What does heartbeat A, B, C mean? I guess based upon what I read above that it is a check for a functioning Pad box A and B and the LCO box?

That's about right. As I mentioned before the heartbeat LEDs provide important feedback. For example, they will flash quickly if the wired or wireless connection to their corresponding pad group isn't working. Maybe the pad group isn't turned on. Otherwise they blink a slow, steady heartbeat.
 
I may have missed it earlier, I just read this thread. Have you come up with a final price yet?

You didn't miss it. I've been avoiding the topic. I don't know yet if I would offer to build these to barter or sell. Lots of issues there to consider. But I'm not fundamentally opposed to the idea.

This thread is intended to inform--pass on a few ideas and concepts--and force me to document in pictures (for myself and others) what I have been doing these last few years. And also to entertain.

Building more of these would be easier, actually, since I wouldn't have to take so many dang pictures.
 
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I'd be very interested to see some of the guts of the code you're gonna drop in the PIC; I've been considering a very similar project (based on the same hardware architecture) and would love to compare notes. Looking forward to the rest of the build!
 
Just a preview on the field box. Lots of options there.

First photo is just for scale. Middle is the bottom panel. Last is the top panel. These are 1/4" hardboard. Nothing fancy.

The orange tool box is perfect. For visibility one, and also supporting the relay controller form factor. A nice inexpensive package overall.

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These are some field box layout options. The first photo is typical of a 4 pad high-power or remote node. The board is tilted to allow room for the wireless antenna connection. The battery can be external or internal.

The second photo shows a configuration that has wireless module with a patch antenna. FCC approved also but much shorter range than the external dipole. I field tested this antenna to about 130 feet. So it is good for most LPR and MPR layouts.

The patch antenna config allows two complete 4 pad modules to in exist in the one field box. This is great for some higher density low/mid power layouts. As the last photo basically shows

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You didn't miss it. I've been avoiding the topic. I don't know yet if I would offer to build these to barter or sell. Lots of issues there to consider. But I'm not fundamentally opposed to the idea.

This thread is intended to inform--pass on a few ideas and concepts--and force me to document in pictures (for myself and others) what I have been doing these last few years. And also to entertain.

Building more of these would be easier, actually, since I wouldn't have to take so many dang pictures.

David,

I understand your hesitation on selling/trading these units. It's a huge difference between building something for yourself, and building something for others to use.

Would you be willing to let us know what you would consider selling these for IF you do happen to choose to go that route?

The reason I ask is that I am basically building a similar system. I'm using ATmega chips instead of PIC chips, but fundamentally the same concept. I'll be starting a new thread for it at some point in the future when I'm closer to having something to show everyone.

Anyways, I'm also debating the personal use vs selling the units, and I've been tweaking with the overall design based on the price point. Just the raw materials on my current design would cost ~$150 for the controller, and ~$100 for the pad boxes. Given the way my projects go, the end materials cost will likely be double that. I'm assuming that most individuals wouldn't spend that kind of money for a launch system, so the only "buyers" would be clubs. With that target audience, I can see that my original design (for my personal use) wouldn't work for a club, so I'm revisiting the design to see if I can make reasonable changes (software and hardware) that would make it a "club" capable launcher without affecting the material price too drastically. If I can't adjust, I'll go back to my original plan and make one for myself. If I can make the changes reasonable, I may open it up and offer it to clubs as a design for free, ready-to-assemble kits, pre-built units, or some combination thereof.

Back to the original point... It may be worthwhile to get an idea of how many people would be interested in buying at certain price points, and use that as a factor in making your decision.

Cheers,
- Ken

PS: Love your work on this so far. Absolutely beautiful.
 
I would have to disagree on the price. There is only 1-2 other units out there. My clubs like my own are in dire straights and need a new system. We are currently looking at the options out there and they are slim.

Look at the cost of wire. 1500 feet is about $100-180 depending on the type. If you go with flat phone, it is near $100. if you go with plenum Cat5, it will cost $140-160 per 1000'. Wireless is a savings.

I just priced a fireworks system in a pelican box. $1300 to run 3 pad boxes that will control up to 18 pads per box.

Not cheap.
 
I would have to disagree on the price. There is only 1-2 other units out there. My clubs like my own are in dire straights and need a new system. We are currently looking at the options out there and they are slim.

Look at the cost of wire. 1500 feet is about $100-180 depending on the type. If you go with flat phone, it is near $100. if you go with plenum Cat5, it will cost $140-160 per 1000'. Wireless is a savings.

I just priced a fireworks system in a pelican box. $1300 to run 3 pad boxes that will control up to 18 pads per box.

Not cheap.

For a club, I agree. For an individual, I don't think that $250 for a wireless system makes a lot of sense.

That's why I'm tweaking my design to see if I can make it something a club would want.
 
The reason I ask is that I am basically building a similar system. I'm using ATmega chips instead of PIC chips, but fundamentally the same concept. I'll be starting a new thread for it at some point in the future when I'm closer to having something to show everyone.

That's great. I'm curious to know how many pads your design will support, and what you are using for wireless radios?

I can't wait to see your thread.

My parts cost appears somewhat higher than yours (but maybe not, if you were talking about $ for a personal system) but I am also at a point in the design where I know exactly what every cost is. And it does add up.

My system is obviously designed for club use. But there's no reason a 4 pad version couldn't be used as a personal system.
 
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