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A small Yagi antenna on either end for 900 MHz would work fine, since you know where it is and it's not moving.
How To Build A Wireless Launch Controller
- Thread starter llobdelljr
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You could also use patch antennas. I have built one for 434MHz which is a bit bulky, but 900MHz would be much more manageable
https://www.rc-cam.com/gp_patch.htm
Just search for "goof proof patch antenna" if you forget the URL
https://www.rc-cam.com/gp_patch.htm
Just search for "goof proof patch antenna" if you forget the URL
What is the general concensus regarding the transmitted packet structure for a wireless launch controller? Presumably it would require some redundancy and error checking. Would it use, perhaps, a Modbus-type protocol, or something more (or less) sophisticated? Is encryption recommended?
Using built in AES encryption is a good starting point. Most of the non-licensed band transceivers have this. It certainly will reduce the chance of having a similar transmission from being mis-guided.
I have been in discussion with Brad for the last week, since this thread started. I have suggested we provide an open source single wireless pad\controller based using an Arduino Uno. He has been very busy however I have finished a design for a shield and expect a proto from the board mfg by Friday. As soon as I verify the artwork. I have permission to release the software for both the controller and the pad unit as well as the artwork and schematics. I think Brad is also considering providing boards at near cost since most people would rather spend the tooling cost for a board layout on rocket parts.
Dan
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Howdy all you Do it Yourselfers:
I wonder if anyone would be interested in a DIY Wilson F/X wireless based system kit.
Like Dan said, he and I have been kicking this idea around and we’ve decided that now is the time to put it out there to see if there’s enough interest to produce a build it yourself, single-pad, W-F/X wireless, Arduino based, open source encoded, launch system for the do it yourselfers among us.
We have designed a shield to stack on Arduino units that will allow the do it yourselfers among us to build a safe reliable wireless single pad launch system.* We will use Arduino UNO units to build our shield prototypes.
The circuit board that fits on top of your Arduino unit is a “shield” that will work on one Arduino as a launch controller and on your second Arduino as a pad-box.* The two shields will naturally be populated with slightly different components for those two purposes.* But it will be the same bare circuit board for both.
The Wireless part of this unit will use the same encryptable Xbee 900hp units that we use in our Wilson F/X club systems. So you’ll be able to operate out to a mile depending on which antennas you connect to your units.
And it will have continuity reading at the pad and from the controller.* Plus we will be supplying all the parts for the circuit boards including the XBee units.* This does not including antennas or antenna connectors, switches, key switches, wiring, igniter leads, enclosures, etcetera. *The kit is just the shields and parts for the shield, ready for the do it yourselfer to solder on the parts and create the rest of your personal wireless launch system.
We are hoping that the price tag can be somewhere between $180 (if we only get a dozen buyers) and $150 dollars (if we can get 50 buyers) for a wireless launch controller and a wireless pad-box shield for your Arduino units.* The more people who are interested, the lower the price can be.
So…. Any interest out there?* There would be a serious investment cost for Wilson F/X which is why we are looking to see if there’s enough interest before we put down the cash to start producing them.
Brad, the “Rocket Rev.,” Wilson
Wilson F/X Digital Control Systems
I wonder if anyone would be interested in a DIY Wilson F/X wireless based system kit.
Like Dan said, he and I have been kicking this idea around and we’ve decided that now is the time to put it out there to see if there’s enough interest to produce a build it yourself, single-pad, W-F/X wireless, Arduino based, open source encoded, launch system for the do it yourselfers among us.
We have designed a shield to stack on Arduino units that will allow the do it yourselfers among us to build a safe reliable wireless single pad launch system.* We will use Arduino UNO units to build our shield prototypes.
The circuit board that fits on top of your Arduino unit is a “shield” that will work on one Arduino as a launch controller and on your second Arduino as a pad-box.* The two shields will naturally be populated with slightly different components for those two purposes.* But it will be the same bare circuit board for both.
The Wireless part of this unit will use the same encryptable Xbee 900hp units that we use in our Wilson F/X club systems. So you’ll be able to operate out to a mile depending on which antennas you connect to your units.
And it will have continuity reading at the pad and from the controller.* Plus we will be supplying all the parts for the circuit boards including the XBee units.* This does not including antennas or antenna connectors, switches, key switches, wiring, igniter leads, enclosures, etcetera. *The kit is just the shields and parts for the shield, ready for the do it yourselfer to solder on the parts and create the rest of your personal wireless launch system.
We are hoping that the price tag can be somewhere between $180 (if we only get a dozen buyers) and $150 dollars (if we can get 50 buyers) for a wireless launch controller and a wireless pad-box shield for your Arduino units.* The more people who are interested, the lower the price can be.
So…. Any interest out there?* There would be a serious investment cost for Wilson F/X which is why we are looking to see if there’s enough interest before we put down the cash to start producing them.
Brad, the “Rocket Rev.,” Wilson
Wilson F/X Digital Control Systems
I'm interested.
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Hello Mr. Eggtimer Rocketry,
I'm sorry that I don't know your name so that's as close as I can get for now. I'm unfamiliar with your products, but that's mostly because I'm up past my eyeballs trying to keep inventory ahead of sales and its not easy. I'm getting ready for club system #34 and individual system #12 in case you're curious about that sort of thing.
So...., you are curious to see what we at Wilson F/X use for our keyswitch arming/disarming mechanism? That's easy.
First off, we use a literal keyswitch with a removable key that we get from Digikey: part number CKC8039-ND in case you are interested. Its an expensive but high quality key switch, but it will no doubt last longer than the 10 years for which we guarantee our internal circuit boards.
We put the keyswitch in the power up circuit on the LCU-64/128 circuit board itself which makes it "in-line" with the firing button for the launch controller itself. Without power it is impossible for a Wilson F/X launch controller to launch anything. Remove the key and a Wilson F/X system is safe, safe, safe. Without power no bank of pads can be selected or armed. Without power no pad can be selected or fired. Pretty simple really.
The only way to fire an igniter on a pad with Wilson F/X technology (not including using the ARMAGEDDON switch) is to have the key in the key switch, the controller connected to a viable 12v power source, the keyswitch turned on, a single bank of pads selected/armed, and for the desired pad(s) to be selected.
I suppose if someone wanted to actually sabotage a Wilson F/X launch system in order to purposely fire a rock from at the pad, one could open up a Wilson F/X Pad-Box and physically bypass the pad-box's circuit board directly dumping 12v from the bank/pad's battery into the igniter leads. But other than by direct intentional sabotage, there's no way to make a Wilson F/X pad-box fire an igniter without using a Wilson F/X launch controller.
And to the gentleman who thinks that this is an inappropriate response to the origin of this thread, I will quote llobdelljr's original post for this thread: "Does anyone have plans/suggestions for building/buying a one pad wireless launch controller with a minimum range of 1000 feet?"
He specifically asks for plans to build and/or suggestions for buying. So if my responses sound like an advertisement... well he did ask for suggestions where to buy.
Brad
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Brad, thanks for the explanation. Yup, disabling power to the transmitter circuit would for sure keep it from firing! BTW, I fly with ROC, and the Wilson FX system that they bought was a terrific investment. It's a very high quality piece of equipment, very reliable, and has made setup and teardowns an order of magnitude easier.
This post hopefully will have the schematics for the proposed Shield configured as a Control Shield and a Pad Shield. View attachment Launch Control Shield.pdfView attachment Launch Pad Shield.pdf
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The title of the thread notwithstanding? ;-)
At the time I left my message, you were solely in advertising mode. Now you're fishing for feedback on offering a commercial kit. Still, I see no specific plans other than "buy my existing product or my future kit".
I think the response to how many people are interested in the kit will depend on a review of the schematic and other details.
mikec
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Interesting. It's not immediately clear how you have the Xbees configured or how the I/Os are being used.
If one is going to go to the trouble of making a board layout, supporting more than one channel would be nice. The XBee can handle up to 15 DIOs, I think. Seems like at least four relays would fit in the Arduino form factor.
UhClem
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What is the intended purpose of the IRLD112 MOSFET on the pad shield that has its gate connected to Vdd? (Reference designators would help!)
I wanted to know the threshold voltage but I cannot find that part number anywhere.
Reverse Battery protection.
Sorry, try IRFD112.
I made the two schematics from one which includes both board components. I am attaching it to this message so you can see the part designations.
View attachment Launch Pad_Control Shield.pdf
The XBee units are configured in transparent mode, essentially the two Arduino units would be able to send and receive serial information between them. The serial ports from the XBee units are voltage buffered through the 4050 to the Arduinos. Also the Arduinos would communicate through the software serial library to allow the hardware serial to continue to work through the USB port. This will allow the user to debug and program new software without having to disconnect the XBee units.
This project is intended as a single pad/controller.
UhClem
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It would be cheaper and just as effective to connect the relay coil to "BAT" instead of "PWR".
Are those two lonely ground symbols the same net as those labelled "GND"?
True, however, I was attempting to isolate the spike from the recycling diode when the relay is released, since the shield will provide the power to the Arduino I was being extra careful.
Yes they are on the same node. I can change them if you think it is appropriate.
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mikec
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If you used the Xbees in DIO line-passing mode (see https://learn.adafruit.com/xbee-radios/reference or https://www.digi.com/blog/videos/xbee-tech-tip-digital-io-line-passing-with-xbee/ ) then you could skip needing the Arduinos completely. Just an idea.
mikec
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From reading the datasheet, I'm pretty sure (though not positive) that it is supported in the 900HP, but you'd have to try setting it up in XCTU to be sure.
Going to stick to transparent serial mode, although you are welcome to try it yourself.
I would also be interested. While schematics would be interesting, I would trust the Wilson thought and ingenuity would go into the design and system components - so that would be good enough for me.
UhClem
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How would that work?
When Q1 turns off the relay coil is isolated from ground. The only way that could change is if the voltage on the drain of Q1 became negative so that the body diode conducts except that the relay is pulling it high. Or the voltage could rise high enough to push Q1 into breakdown but it can't do that because of D3.
Because the IRFD112 is avalanche rated, you don't even need the diode on the relay coil. Although I would still use it.
Q2 is a waste of space and because of the marginal ratings of the IRFD112 it could prevent the circuit from pulling in the relay under some conditions.
They must be the same net or the circuit will not work.
First, the schematic capture I use will accept both as the same node. I don't normally share these so it was not really an issue for me. I understand the confusion and will make them the same.
As far as flipping the FET and using it as a reverse battery, I guess the only thing I might have to change is connecting the gate to Battery instead of 5V.
UhClem
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I can see several single point failure modes that would result in an energized output. With no warning unless you tap the clips together.
1) RLY1 contacts shorted. A not uncommon failure mode.
2) Q1 fails energizing RLY1
3) The Arduino fails turning on Q1.
At the bare minimum there should be an audible warning if the relay is closed. Better would be to include that and remove the single point failure modes.
The simplest being to have the relay switch the high side when the arm key switch on the controller is enabled. Then use a low Rds(on) FET to switch the low side. You might need a FET driver to fully enhance it. (The MIC5018 is my favorite.)
In addition a pad side safe/arm switch that disconnects the igniter outputs from the electronics is a very good idea. (DARS has had good results with 20A DPDT toggle switches.) Otherwise this system is totally dependent on the software operating correctly. Proving software correctness (not only what you write but in the Arduino libraries and in the XBee) is hard.
The keyswitch is wasted as it serves no useful purpose.
1) RLY1 contacts shorted. A not uncommon failure mode.
2) Q1 fails energizing RLY1
3) The Arduino fails turning on Q1.
At the bare minimum there should be an audible warning if the relay is closed. Better would be to include that and remove the single point failure modes.
The simplest being to have the relay switch the high side when the arm key switch on the controller is enabled. Then use a low Rds(on) FET to switch the low side. You might need a FET driver to fully enhance it. (The MIC5018 is my favorite.)
In addition a pad side safe/arm switch that disconnects the igniter outputs from the electronics is a very good idea. (DARS has had good results with 20A DPDT toggle switches.) Otherwise this system is totally dependent on the software operating correctly. Proving software correctness (not only what you write but in the Arduino libraries and in the XBee) is hard.
The keyswitch is wasted as it serves no useful purpose.
Responses are in reverse order:
The keyswitch is normally on used on the controller, it can be left off on the pad side. The keyswitch will provide power to the Arduino as well on the controller side.
Yes you can add a 20A switch to the leads if that is something you wish to do. Yes, the system is dependent on software for operating correctly, as are most things these days.
I agree the list of single point failures potentials, yes the Relay shorting is uncommon, even more uncommon will be Q1 failing. In the last 17 years we have had one relay fail and it failed open. We have had no failures of the driver to the relay.
That being said every launch system (electrical or electronic) has the potential for failure and utmost caution should be observed when attaching leads. (to the point of removing the battery or having quick disconnect leads removed from the pad box)
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