Wireless Hybrid GSE

[kramer714]

I have been using a wired hybrid GSE for years. Dragging cables isn't really much fun, A few years ago I made a wireless interface box for my hybrid setup, it worked ok ,but really not a true wireless system.

I decided to do a totally new hybrid wireless system from scratch. The system has;

• 1KM wireless range
• relays for fill, vent, and fire
• independent relay for arming (2 degree redundancy)
• Solenid Saver RC Circuit for fill and vent
• Internal battery for control box
• external battery for pad box
• manual control of fill and vent from pad box (really important feature)
• volt meter in both boxes
• 12v dry cells for both boxes

For the wireless system I used

• 4DI 4DO 433 MHz system Eletechsup N4RFA04
• https://www.ebay.com/itm/195749225648 (also available on Amazon)

I picked this for a few reasons, I liked that you can change the frequency plus (not that I am using it now) the ability to connect to RS 485

 

[kramer714]

Wireless Controller

For the controller side of things, I used a off the shelf 6x6x4 inch Conduit box
https://www.homedepot.com/p/Carlon-6-in-x-6-in-x-4-in-Gray-PVC-Junction-Box-E987RR/100404096

Cutting the exiting box for all the attachments sounded like too much work, so I 3D printed the lid, complete with all of the features. Saved lots of time plus it makes it simple to put in features like locking tabs and the flats on the side of a hole that 'clock' things like the key switch.

Came out well, I did add a 'placard' for the switches

 

[OzHybrid]

It's a great idea in theory. But I'd still use hard wired. I use hard wired to a remote box so all control is over a stranded cable cat5. It would be easy for you to include that too.

I've seen too many wireless systems get a glitch at some point. On a solid that just means you have to wait a minute and go and find the issue. On a hybrid, if the tank had started filling, you'd have to dump the nitrous before you could approach it. It just takes someone on the same frequency to swamp your signal. They're great when they're great and a pain when they're not.
1000 ft/ 300m of cat 5 pretty much fits on a standard garden hose reel. You could even feed power on a pair to keep the remote battery charged.
Don't forget to include solenoid saver circuitry to reduce the power to your solenoid once opened. Stops them burning out on long fills.
Norm

 

[Art Upton]

Most of the good remote controllers for AP or Hybrids use 900mhz or 2.4mhz X-Bee type technology with spread Spectrum and digital coding passwords to keep from being swamped.

For Example you don't see RC model aircraft falling out of the sky on swamped signals anymore once they went digital.

Now-a-days LoRa technology might be even better and you can get those on Amazon

 

[OzHybrid]

Most of the good remote controllers for AP or Hybrids use 900mhz or 2.4mhz X-Bee type technology with spread Spectrum and digital coding passwords to keep from being swamped.

For Example you don't see RC model aircraft falling out of the sky on swamped signals anymore once they went digital.

Now-a-days LoRa technology might be even better and you can get those on Amazon

Hi Art,
The performance of a transceiver depends on the system overall. It could be a reset due to a power glitch from a heavy duty solenoid or the back emf from it switching off. I'm not saying swamping is the ONLY way for them to glitch. And I'm not saying solenoid switching is the only other potential issue.
Just that for the duration of the fill fire/dump(if required) for hybrids, it's a LOT longer it has to perform flawlessly for.

The RC systems today are a lot better, but tend to work with a set of known building blocks. If you google RC glitches, you'll find plenty of evidence they do still occur for various reasons.
I worked in the security industry where secure wireless technology is widely used. Nothing outperforms hard wired for reliability.
YMMV.

 

[Art Upton]

Hi Art,
The performance of a transceiver depends on the system overall. It could be a reset due to a power glitch from a heavy duty solenoid or the back emf from it switching off. I'm not saying swamping is the ONLY way for them to glitch. And I'm not saying solenoid switching is the only other potential issue.
Just that for the duration of the fill fire/dump(if required) for hybrids, it's a LOT longer it has to perform flawlessly for.

The RC systems today are a lot better, but tend to work with a set of known building blocks. If you google RC glitches, you'll find plenty of evidence they do still occur for various reasons.
YMMV.

JMRC here in my area has been using X-bee designed AP/Hybrid controllers now for almost a decade. I created a fail safe prototype of Arduino code for the X-Bees to communicate two ways of all phases of connect, establish, control, launch, abort.

Tony Hega finished the prototype for the club and added more features.

The Rocket Reverend in Tripoli has been selling Wireless controllers for the big Tripoli high power launches for almost a decade as well.

And PPS I have not seen at my R/C club airplanes failing out of the sky like I did in the 90s when we were on 72mhz analog or PCM. The newest Digital RX for R/C will even fly the plane should "you" freeze up and will level it out.

 

[OzHybrid]

JMRC here in my area has been using X-bee designed AP/Hybrid controllers now for almost a decade. I created a fail safe prototype of Arduino code for the X-Bees to communicate two ways of all phases of connect, establish, control, launch, abort.

Tony Hega finished the prototype for the club and added more features.

The Rocket Reverend in Tripoli has been selling Wireless controllers for the big Tripoli high power launches for almost a decade as well.

And PPS I have not seen at my R/C club airplanes failing out of the sky like I did in the 90s when we were on 72mhz analog or PCM. The newest Digital RX for R/C will even fly the plane should "you" freeze up and will level it out.

How about publishing the design and code. Give everyone a good starting point.

 

[Art Upton]

How about publishing the design and code. Give everyone a good starting point.

The Idea and block diagrams, but not the code, was already published some years ago. The was not released as the last person to work on it did not want liability issues. It was published in the year by year winning NAR section newsletter "Total Impulse"

I'll send an email to Tony and he should know the year/month of it.

 

[OzHybrid]

The Idea and block diagrams, but not the code, was already published some years ago. The was not released as the last person to work on it did not want liability issues. It was published in the year by year winning NAR section newsletter "Total Impulse"

I'll send an email to Tony and he should know the year/month of it.

Thanks Art,
Looking forward to having a read.

 

[Voyager1]

Nice work and good luck with the build and testing.

I had been using a homemade wired hybrid system for several years until I decided to purchase the WFX wireless hybrid launch system last year. They are well built and very reliable - I won’t be turning back to a wired system.

I understand Norm’s argument for a wired system, but even with a wired system things can still wrong, and have, in my experience. Field cables can be damaged, connectors can oxidise and get dirt or moisture in them causing connection problems. I’ve had all that.

 

[kramer714]

It's a great idea in theory. But I'd still use hard wired. I use hard wired to a remote box so all control is over a stranded cable cat5. It would be easy for you to include that too.

I've seen too many wireless systems get a glitch at some point. On a solid that just means you have to wait a minute and go and find the issue. On a hybrid, if the tank had started filling, you'd have to dump the nitrous before you could approach it. It just takes someone on the same frequency to swamp your signal. They're great when they're great and a pain when they're not.
1000 ft/ 300m of cat 5 pretty much fits on a standard garden hose reel. You could even feed power on a pair to keep the remote battery charged.
Don't forget to include solenoid saver circuitry to reduce the power to your solenoid once opened. Stops them burning out on long fills.
Norm

Cable vs Wireless - From my experience (YMMV) the cable is one of the biggest issues for reliability plus the hose reel (I have that for one of my wired systems) take up a lot of room in the car. I use shielded cat5, one of my wired setups uses a hose reel, the other uses a simple (smaller) cable reel. When I first stated in hybrids, the clubs I launch with all were wired, one thing about that is I always knew how far the pads would be. Now that they are all wireless, the distances seem to get longer, I remember one launch where my wired box was sitting on a chair 50' on the range.

Frequency - As far as frequency, the RF relay box I'm using gives you 16 choices of frequency between 426 and 508 MHz. Not ideal but does give some level of protection. I do have a LoRa setup coming. Same (or smaller) form factor, I can swap that out in the future if I need.

Programmed vs hardware based. I do some programming, but wanted a simple hardware based solution. Just a personal preference, I do appreciate what you can do with a programmable system.

Relays and Solenoids - For the fill and vent, I do have a RC circuit set up ( solenoid saver - picture attached), I'm using 40 amp / 12V Bosch relays. These are VERY 'kick resistant' and are not affected by sitting in a sealed box, in July, in the sun, in the summer, in the desert. For the day job I do use SSR, but they do like to have some cooling, not ideal for a pad box.

Safety - Pad Side

• Master Relay - There is a NO relay that is energized by a Digital Input on the transmitter, just turning on the transmitter doesn't turn on any relays. The master relay is energized by the key switch on the transmitter box. This also turns on a loud buzzer at the pad box.
  • two relays on the pad box need to be energized for ANY remote action to happen, any single stuck relay can not cause an un-commanded fill, vent or fire.
• Arming Switch on the pad box - There is an arming switch on the pad box, with a swtich cover (close the cover turns off the switch) with the switch off, the push buttons on the pad box CAN energize the fill or vent solenoid. I like to have this ability at the pad. With the switch ON, the transmitter can control the box.

Safety - Transmitter Side

• Key switch controls master relay
• Fire command requires (3) independent actions
  • Key switch must be on
  • Arming Switch must be on - requires opening the switch cover - this turns on the indicator light on the fire button. Switch can not be on with the switch cover down.
  • Fire button must be held pressed
• Fill / Vent requires (2) independent actions
  • Key Switch must be on
  • Fill switch or Vent Switch must be on - requires opening the switch cover. Switch can not be on with the switch cover down.

 

[kramer714]

but even with a wired system things can still wrong, and have, in my experience. Field cables can be damaged, connectors can oxidise and get dirt or moisture in them causing connection problems. I’ve had all that.

Yup, plus where i launch the soil is very sticky and corrosive..... Not to mention people tripping over / driving over the cables.

 

[kramer714]

I had been using a homemade wired hybrid system for several years until I decided to purchase the WFX wireless hybrid launch system last year. T

ROC uses the Wilson System, been very reliable and has stood up to busy club use. Not cheep but a reasonable price for what you are getting. I decided to build my own for a few reasons,

• Save few $ (you know the old saying, it only cost a little more to do it yourself)
• I like building stuff...
• Biggest reason, by building it myself I am REALLY familiar with all of the parts, how it is assembled and how to repair / diagnose any issues.
• Able to modify / update in the future.

Mike (geek masochist) K

 

[Tim Covey]

I looked at the RS485 units and they seem ok, I like the non standard frequency options to limit crossover of 426MHz~508.5MHz..
I do worry about ultimate "Real" range... 1k could be questionable in real use and always overstated even with antenna mods. The bi directional option,. also is the RS 485 function to be used, not sure I see a real need.
I dont see frequency crossover a problem more than any other system, running out up to 1500 ft of wire is a waste of valuable field time.

They RS485 unit looks good enough,, but I went looking around, 2 are needed and 8 function units are available bringing the price of x2 to $44 or so, cheaper for a pair on AliExpress. Also looking I feel that the simple switch state feed back or being bi-directional would be useful in direct pad feedback of full "thermistor" , filling, continuity features and or general out of sight operation,, short of full load cell feed back, single point indication can do a lot.

As a Hybrid guy myself I find field time spent and ease of use important, leads myself to something like this. I'm building hybrids not launch controllers. I also dont care about RS485 if it can be got around.
I did find these appealing options, 2x more expensive but use lora and would have MUCH longer range including the Lora error correction abilities. Along with simpler use "no program coding" and Very Simple Bi directional feed back an integrated part and even wider frequency's . The down fall is only 4 channels..
The only extra need in reality would be loadcell fill feedback, but I found a wireless 300lb scale using NRF24l01 for $50 was my trick. .
https://www.aliexpress.us/item/2251832187210489.html?spm=a2g0o.productlist.main.29.3ba916dd19WL4b&algo_pvid=020bfb52-7217-4a7a-8c91-4c5121b4a4f9&algo_exp_id=020bfb52-7217-4a7a-8c91-4c5121b4a4f9-15&pdp_npi=3@dis!USD!115.5!90.09!!!!!@211bd4cd16859041194596966d07fa!56728928984!sea!US!2104885182&curPageLogUid=iK2TZ2VRQQwt

 

[Voyager1]

ROC uses the Wilson System, been very reliable and has stood up to busy club use. Not cheep but a reasonable price for what you are getting. I decided to build my own for a few reasons,

• Save few $ (you know the old saying, it only cost a little more to do it yourself)
• I like building stuff...
• Biggest reason, by building it myself I am REALLY familiar with all of the parts, how it is assembled and how to repair / diagnose any issues.
• Able to modify / update in the future.

Mike (geek masochist) K

I also love designing and building stuff! However, when I did the sums to build my own design for a wireless hybrid system, I was only saving on shipping when comparing costs. Prices for many electronics components have risen significantly in Oz over the last few years. So, I decided to go with the WFX system. This decision followed the purchase of a full WFX wireless launch system by our club and also an associate club. We had combined our orders to keep the shipping costs down. However, I was so impressed with the quality of the design and build, and technical support, that is was an easy decision for me to make to purchase the hybrid system.

 

[kramer714]

I looked at the RS485 units and they seem ok, I like the non standard frequency options to limit crossover of 426MHz~508.5MHz..
I do worry about ultimate "Real" range... 1k could be questionable in real use and always overstated even with antenna mods. The bi directional option,. also is the RS 485 function to be used, not sure I see a real need.
I dont see frequency crossover a problem more than any other system, running out up to 1500 ft of wire is a waste of valuable field time.

They RS485 unit looks good enough,, but I went looking around, 2 are needed and 8 function units are available bringing the price of x2 to $44 or so, cheaper for a pair on AliExpress. Also looking I feel that the simple switch state feed back or being bi-directional would be useful in direct pad feedback of full "thermistor" , filling, continuity features and or general out of sight operation,, short of full load cell feed back, single point indication can do a lot.

As a Hybrid guy myself I find field time spent and ease of use important, leads myself to something like this. I'm building hybrids not launch controllers. I also dont care about RS485 if it can be got around.
I did find these appealing options, 2x more expensive but use lora and would have MUCH longer range including the Lora error correction abilities. Along with simpler use "no program coding" and Very Simple Bi directional feed back an integrated part and even wider frequency's . The down fall is only 4 channels..
The only extra need in reality would be loadcell fill feedback, but I found a wireless 300lb scale using NRF24l01 for $50 was my trick. .
https://www.aliexpress.us/item/2251832187210489.html?spm=a2g0o.productlist.main.29.3ba916dd19WL4b&algo_pvid=020bfb52-7217-4a7a-8c91-4c5121b4a4f9&algo_exp_id=020bfb52-7217-4a7a-8c91-4c5121b4a4f9-15&pdp_npi=3@dis!USD!115.5!90.09!!!!!@211bd4cd16859041194596966d07fa!56728928984!sea!US!2104885182&curPageLogUid=iK2TZ2VRQQwt

I do have a LoRa tx/rx from aliexpress coming, LORA TX/RX, simple feed back, but not much more. I have been told these LoRa systems should have longer range. I plan to play with it.. see what it can do.

Range - As far as range goes, what do I really need? I picked 1km figuring that is much longer than what I really need. For most of the hybrids I am launching, 1,000 feet (300m) is more than enough, with 2,000 feet (600m) probibly the longest i could need. I picked 1km range to add a factor of safety. Despite the 2km range 'advertised' I think I should be fine at at least 600m.

Antenna / range - I have thought about getting a directional antenna for the Rx to play with and see what it does to the range. Im not an antenna guy, any suggestions would be appreciated.

 

[Handeman]

We just have the small 5" - 6" tall foldable antennas on our controller and pad boxes. The pad boxes are about 12" tall. It works just fine at the away cell up to 1000 ft. The closer pads have issues once in a while because there is a small rise between the pad boxes and the controller which puts the line of site too close to the ground. We replaced the folded one on the pad boxes and now use a small antenna on the end of a 42" fiberglass rod we stick into the ground. It raises the antenna just enough to eliminate the issues with the ground. Height is your friend.

 

[rocket_troy]

I also built my own GSE - probably the 5th iteration. Been down the load cell and temperature monitoring path before, but... too much hassle for me. It's okay when everything works perfectly 1st go, but it's quite distracting when it doesn't. So, I've settled for a minimalist approach. Similar 1km RF range. Packed everything into a tiny box - battery, RF control, 2 solenoid saver circuits, high brightness LED indicator etc. That box slips onto an acrylic strip that slips into my thermal blanket sleeve. Very quick setup with no distractions since I sorted the solenoid saver circuits out (needed a lower resistor value).
The LED indicator is plugged in via a standard DC plug & socket allowing 360 degree rotation and height adjustment via the short coolant hose arm.

TP

 

[kramer714]

I also built my own GSE - probably the 5th iteration. Been down the load cell and temperature monitoring path before, but... too much hassle for me. It's okay when everything works perfectly 1st go, but it's quite distracting when it doesn't. So, I've settled for a minimalist approach. Similar 1km RF range. Packed everything into a tiny box - battery, RF control, 2 solenoid saver circuits, high brightness LED indicator etc. That box slips onto an acrylic strip that slips into my thermal blanket sleeve. Very quick setup with no distractions since I sorted the solenoid saver circuits out (needed a lower resistor value).
The LED indicator is plugged in via a standard DC plug & socket allowing 360 degree rotation and height adjustment via the short coolant hose arm.





TP

Clever use of the LED holder. Impressed that you could get that all into the small box. The 10 x 10 x 4 I'm using is pretty full.

Couple of questions, is this just fill / vent? Doesn't look like it has ignition too.

What radio did you use? something off the shelf or did you make something?

Mike K

 

[Handeman]

A couple of our members have started flying Hybrids again. The issue they've had is seeing the vent plume when the motor tank is full. One was talking about using a sensor, temp sensor I think, to sense the vent plume when the tank is full.

Have you incorporated a sensor so you get a light on your control panel when the tank is full?

 

[kramer714]

I gave up on trying the thermistor / temp sensor. Had a few incomplete fills when using sensors people brought. I just visibly look for the plume. Another reason for a wireless system, easy to get a little closer for visual, then back off when filed.

To help with seeing the plume, I always position the vent tube 90 degrees from the launch lugs, sounds obvious but easy to forget this. Plus I have found that leaving the vent tube a few inches long makes it easier to see the plume. Side note, on the Trojan Hybrids, you can hear when the tank is totally full.

I think a fill detector could work, but nothing i need at this point.

 

[rocket_troy]

Clever use of the LED holder. Impressed that you could get that all into the small box. The 10 x 10 x 4 I'm using is pretty full.

Couple of questions, is this just fill / vent? Doesn't look like it has ignition too.

What radio did you use? something off the shelf or did you make something?

Mike K

Yeah, just fill and dump. I rely on the club's controllers for the ignition, so for them (the LCO) it's just pressing the fire button like a solid, once I give the go-ahead.
Like you IIRC, it's just some cheap Chinese modules. I settled on those maybe 12 years ago Ebyte E31 (various power outputs) but they're probably obsolete now. Nevertheless, they work. Used them for flight electronics and various other stuff.

Troy

 

[rocket_troy]

I gave up on trying the thermistor / temp sensor. Had a few incomplete fills when using sensors people brought. I just visibly look for the plume. Another reason for a wireless system, easy to get a little closer for visual, then back off when filed.

To help with seeing the plume, I always position the vent tube 90 degrees from the launch lugs, sounds obvious but easy to forget this. Plus I have found that leaving the vent tube a few inches long makes it easier to see the plume. Side note, on the Trojan Hybrids, you can hear when the tank is totally full.

I think a fill detector could work, but nothing i need at this point.

Also, with the design of the vent tube, it's important to have the choke/orifice at the very end/output ie. have whatever diameter line to that point, but ensure that that choke point is smaller in throughput area than the cross-sectional area of anything upstream until that point. This will ensure you always see liquid at the vent even on warm days.

TP

 

[Art Upton]

A couple of our members have started flying Hybrids again. The issue they've had is seeing the vent plume when the motor tank is full. One was talking about using a sensor, temp sensor I think, to sense the vent plume when the tank is full.

Have you incorporated a sensor so you get a light on your control panel when the tank is full?

Back in the day we used my Wireless Cameras to see the vent at the LCO table

 

[Voyager1]

Back in the day we used my Wireless Cameras to see the vent at the LCO table

Very hi-tech! I used 10x50 bins.