Flying Laser Tag

[Fallegon]

Why arnt you using a nano or blue pill?

 

[Duck]

Why arnt you using a nano or blue pill?

I picked the shield form factor for ease. I really didn't want a mess of wires as the whole goal is a setup you can plunk into an existing airframe. That means no breadboard so I would need to make a pcb with pinned connections anyway. I already had an arduino laying around. I looked at a couple of those small boards and they all seemed to come with some compromises on one or more area:

1. Ease of programming (USB versus USB + dongles + plugs, etc)
2. Limits on current from the built in regulator or voltage ranges
3. Speed limits on the processor
4. Lack of 5v
5. Lack of timers or pin-interrupts
6. Fewer pins (I had originally planned on using more)
7. More software setup steps
8. The form factor was actually smaller then what I thought I would need so it would be oddly shaped if you stacked the boards

You can totally work around those or find a good combination. I am not an expert on the options and have never personally used the small form factor boards. I hope with my schematic and code someone will do just that. Please send me one if you do

My ideal setup would be:

• micro-USB
• 5v
• able to directly power from tap on 2-4S flight pack (filtering and voltage regulation)
• at least 500mA on 5v regulator
• single PCB with processor and my really tiny logic & pin headers
• as fast or faster then an Arduino Uno
• enough timers/pin-interrupts to make IR RX/TX and PWM receiver reading all work at the same time
• no additional setup for using Arduino code
• space on the board for the single top mounted IR dome (to enable the simplest setup)
• built in wireless for control & reporting scores
• onboard OSD and headers to connect FPV camera / TX

Creating that is beyond my current skill level. The above was my first PCB If you look that is pretty close to what @ioteo came up with. If he makes a product I would probably buy it.

 

[Duck]

I picked the shield form factor for ease. I really didn't want a mess of wires as the whole goal is a setup you can plunk into an existing airframe. That means no breadboard so I would need to make a pcb with pinned connections anyway. I already had an arduino laying around. I looked at a couple of those small boards and they all seemed to come with some compromises on one or more area:

1. Ease of programming (USB versus USB + dongles + plugs, etc)
2. Limits on current from the built in regulator or voltage ranges
3. Speed limits on the processor
4. Lack of 5v
5. Lack of timers or pin-interrupts
6. Fewer pins (I had originally planned on using more)
7. More software setup steps
8. The form factor was actually smaller then what I thought I would need so it would be oddly shaped if you stacked the boards

You can totally work around those or find a good combination. I am not an expert on the options and have never personally used the small form factor boards. I hope with my schematic and code someone will do just that. Please send me one if you do

My ideal setup would be:

• micro-USB
• 5v
• able to directly power from tap on 2-4S flight pack (filtering and voltage regulation)
• at least 500mA on 5v regulator
• single PCB with processor and my really tiny logic & pin headers
• as fast or faster then an Arduino Uno
• enough timers/pin-interrupts to make IR RX/TX and PWM receiver reading all work at the same time
• no additional setup for using Arduino code
• space on the board for the single top mounted IR dome (to enable the simplest setup)
• built in wireless for control & reporting scores
• onboard OSD and headers to connect FPV camera / TX

Creating that is beyond my current skill level. The above was my first PCB If you look that is pretty close to what @ioteo came up with. If he makes a product I would probably buy it.

@Fallegon - If you give up the onboard IR receiver and assume you connect it remotely. You wind up with something like:

This is much smaller but should stack with an Arduino nano. All the IR RX components are moved to the receiver which would require a separate board.

 

[Duck]

I did some measurements and the current weight is:

• All electronics, cases, dome and lens (no battery or connector): 143g
  • Does not include right angle headers or all IR receivers yet (10g?)
  • Lens, frame and IR LED - 50g
  • Case - 23g
  • Lasertagparts.com dome - 7g
  • Amazon dome - 5g
• 2s 500mah Battery + XT30 to barrel jack - 35g

So total weight should be 143g + 10g + 35g = 185-190g . Very manageable on something like the Bronco.

If I switch to an Arduino nano, the weight would go down some. I didn't weigh the board itself but the Arduino is listed as 25g by itself. Some rough math:

• Nano + Sheild = Arduino weight * 2 (for sheild) / 2 for half size = 25g
• Nano Case = Normal case / 2 for half size = 10g
• Lens, frame & IR LED - 50g
• Status LED + leads = 2 * 7g = 14g
• IR Dome + receiver PCB + components + lead = 20g

So total weight for a nano solution would be 119g + 32g (XT30 soldered to board) = ~150g . Not much better. The glass lens is heavy. I bet you could shed another 20g there easily just switching to plastic. I didn't weigh the lens by itself. If you can also shrink the lens diameter and or the focal length, that brings it down even more. Powering it from the flight battery would shed additional weight but no idea if the power would be clean enough. A system in the 100g range would be doable though.

 

[Duck]

It does look like the Arduino Nano Every actually does tick all the boxes and has a listed weight of 5g with headers. I might run my next board with that and see if it works.

https://store.arduino.cc/usa/nano-every-pack

 

[evranch]

Nanos are incredibly versatile and inexpensive. But before you order some...

If you want something extremely powerful, inexpensive and programmable with the Arduino libraries, look at the ESP32 platform.
- dual core, simple to control and send tasks to each core
- more RAM and flash than you will ever need and a ridiculous clock rate for an embedded device
- low power consumption
- wifi and bluetooth onboard
- tons of ADC/DAC/PWM pins
- capacitive touch sensing on most GPIOs
- ten frickin' dollars mounted on a board with power supply etc! Sometimes even with an OLED display, radios or more!

You can take your Arduino program and compile it directly for ESP32 or the ESP8266 (its older and now obsolete brother, single core, less IO).
If you're getting into microcontrollers and building your own PCBs these are definitely worth looking at.

 

[Duck]

I recorded a quick demo with the system. It gives a pretty good sense of how it works. Next up is my Bronco repair and refit so I have a platform to fly it on.

 

[Duck]

Any suggestions for Bronco landing gear for moderate length grass (2-6") ? All the damage so far has been on takeoff when hand launching and I wanted to increase my chances of success. I was thinking of building a pair of bushwacker wheels and just mounting them right under the body right behind the props. The axle would be right against the fuse in a little foam sandwich.

 

[Duck]

Any suggestions for Bronco landing gear for moderate length grass (2-6") ? All the damage so far has been on takeoff when hand launching and I wanted to increase my chances of success. I was thinking of building a pair of bushwacker wheels and just mounting them right under the body right behind the props. The axle would be right against the fuse in a little foam sandwich.

I settled on a pair of bushwacker wheels mounted like a guinea pig. They are a bit ahead of the CG which will help avoid nose overs and lets me put my battery a little farther back. I am almost back in flying shape. My volunteer for taking pot shots at my plane is currently socially distant so I might have to recruit a family member.

Mounting the lens is currently the biggest challenge. The best solution I can come up with is to build a new nose for the Bronco that has an extra tier above the battery to put the lens on. It would fit under the nose just barely but it would take a hit on every grass landing and I don't think it will be strong enough. I'll post pictures once I get everything mounted. I will likely try to fly the bronco without the laser tag setup first as I have not had a good flight on it yet. No reason to break 2 things at once

 

[Boberticus]

how did you decide on a lens? i see that you were using a visiblespectrum LED, did you just turn it on and move the lense back and fourth to find a good focal point?

the dome, its just there to refocus any IR that hits it back to the IR sensor? is that different than this sensor that seems to be built to do just that?

I may have bought some componets thinking id attempt to give it a try, and i think ive got everything to cobble something together, but i have plastic magnifying glasses, and i have that sensor. well see what i can get together.

 

[Duck]

how did you decide on a lens? i see that you were using a visiblespectrum LED, did you just turn it on and move the lense back and fourth to find a good focal point?

the dome, its just there to refocus any IR that hits it back to the IR sensor? is that different than this sensor that seems to be built to do just that?

I may have bought some componets thinking id attempt to give it a try, and i think ive got everything to cobble something together, but i have plastic magnifying glasses, and i have that sensor. well see what i can get together.

I was using the visible spectrum LED just to test. You can't really see the IR beam well except in the dark with an IR sensitive camera. I don't own night vision goggles. The focus isn't exactly the same for the two different wavelengths supposedly but it should be close enough. The lens moves back and forth to focus. Although on my particular lens, you basically use the full length for the right focus. I adjusted the 3d models for r4 (not printed yet) to allow a little extra distance. The lens I picked was my best choice < 10$ that I could buy 1 of. Take a look here for the formula that lets you pick the right lens: https://web.archive.org/web/20180706033641/http://www.lasertagparts.com/mtoptics.htm Basically you control focal distance, lens diameter and LED half-angle. But for each you are limited on what you can actually find. I wanted a high power IR led which meant I could only find 10 degree half angle. That means the ratio of focal length to diameter is fixed for the lens so anything with that ratio works. This was the best one I found. I would MUCH prefer 1" lens with a shorter focal length but I couldn't find one. Fancy scientific ones exist at > 50$ each.

The dome is just protection. On a normal gun you are just avoiding cases where you run into the wall. On an RC plane, replace 'wall' with ground/tree. You can get an IR filtering dome which blocks other light sources which can interfere with the signal but they are not required. The IR sensors themselves have some filtering material on them as well.

If you do try a build, let me know how it works out for you! I have not done distance or flight testing yet. My biggest concern is actually aligning the IR LED & Lens with the FPV camera so you can effectively aim. I am trying to mount everything on my FT Bronco now to actually start trying it out.

 

[Duck]

My bronco gear:

 

[Boberticus]

Have you tried to video tape the shot lit up with your phone? Some phones can see IR some cant, mine cant.

thats a nice little bit of landing gear there. nice to have a big aircraft to test this all out on.

Im pretty sure ive got enough components to build three laser tag units, gonna haft at least two to get proper testing done, the coding is what had got me intimidated, and i had started to look up lens selection too and realized that was a whole nother branch of science, this is all super useful info, thanks for all this!!!

may be building a X-29 so i can fit it all in the removable nosecone

 

[Duck]

New nose job

 

[Duck]

Have you tried to video tape the shot lit up with your phone? Some phones can see IR some cant, mine cant.

thats a nice little bit of landing gear there. nice to have a big aircraft to test this all out on.

Im pretty sure ive got enough components to build three laser tag units, gonna haft at least two to get proper testing done, the coding is what had got me intimidated, and i had started to look up lens selection too and realized that was a whole nother branch of science, this is all super useful info, thanks for all this!!!

may be building a X-29 so i can fit it all in the removable nosecone

Mine can just see the IR LED illuminate but it can't see the projection on the wall well enough to focus it. With the lights out I can barely make out the difference with the LED turned all the way up and it isn't clear enough to focus to lens.

Here are other articles I found on the optics:
https://valentijn.sessink.nl/?p=675
https://github.com/Matthijz98/Open-Laser-Tag/wiki/The-laser-LED-Optics
http://hosting.cmalton.me.uk/chrism/lasertag/lenscalc.html
http://www.lasertag.co.uk/PDF_files/sgconst.pdf

Keep in mind that the lens and frame is quite heavy. Mine was 50g. Putting this all the way in the nose means you need to have room to balance the rest of the plane. You also need a good place for your FPV gear to both aim and see your status LEDs. Nothing prevents you from getting fancy here and using a separate LED strip for FPV status if you want to mount the camera where you can't see your own wings. I tried to keep the code simple enough that it would be easy to customize for this purpose. The X-29 may or may not be suited for the weight distribution or that type of FPV mounting. I haven't built it. How were you thinking of laying out the components?

 

[Boberticus]

i plan on cutting the center of the nose open and center the LED tube, mounting the rest of the electronics on the inside top of the nose so they dont interfere with the battery tray sliding back in, explosions lights can be mounted on either(both?) the wings with a extension to plug in, health bar mounted on top of the fuselage, 130 degree fpv camera mounted back on the V-stab Box thingy so i can see the whole shebang.

sensor on the top of the fuselage and the bottom? seems like you are having no problem registering hits, i just don't want something i can flip upside down and shield from a dive attack ect.

im probably gonna remove the canopy, that should leave me a nice big flat top surface to let me mount a rudimentary hoop style for a targeting reticule. it just occurred to me that my FPV camera might pick up the light. those are some spectacular links on optics, googling this subject was exceptionally difficult

ive got these LEDs and these sensors, the sensors i specially bought because they could be potentially flush mounted in foam, the shielded square bit is about 4mm thick. i need to order some RGB strips, and some lenses.

 

[Duck]

i plan on cutting the center of the nose open and center the LED tube, mounting the rest of the electronics on the inside top of the nose so they dont interfere with the battery tray sliding back in, explosions lights can be mounted on either(both?) the wings with a extension to plug in, health bar mounted on top of the fuselage, 130 degree fpv camera mounted back on the V-stab Box thingy so i can see the whole shebang.

sensor on the top of the fuselage and the bottom? seems like you are having no problem registering hits, i just don't want something i can flip upside down and shield from a dive attack ect.

im probably gonna remove the canopy, that should leave me a nice big flat top surface to let me mount a rudimentary hoop style for a targeting reticule. it just occurred to me that my FPV camera might pick up the light. those are some spectacular links on optics, googling this subject was exceptionally difficult

ive got these LEDs and these sensors, the sensors i specially bought because they could be potentially flush mounted in foam, the shielded square bit is about 4mm thick. i need to order some RGB strips, and some lenses.

The system should support attaching more sensors if you want. There is a small bug in my PCB on that. Following the schematic for the sensor dome PCBs each group of three sensors should have their own cap and resistor. Mine has them all sharing. To fix the board you can cut the power/ground traces to the IR RX header and just wire them to power/ground on any other header.

I am also working out targeting. My big nose has a nice flat surface on top where I can put some pins sticking up to help align everything. These will go right into the lens mount below to keep it straight.

 

[Duck]

i plan on cutting the center of the nose open and center the LED tube, mounting the rest of the electronics on the inside top of the nose so they dont interfere with the battery tray sliding back in, explosions lights can be mounted on either(both?) the wings with a extension to plug in, health bar mounted on top of the fuselage, 130 degree fpv camera mounted back on the V-stab Box thingy so i can see the whole shebang.

sensor on the top of the fuselage and the bottom? seems like you are having no problem registering hits, i just don't want something i can flip upside down and shield from a dive attack ect.

im probably gonna remove the canopy, that should leave me a nice big flat top surface to let me mount a rudimentary hoop style for a targeting reticule. it just occurred to me that my FPV camera might pick up the light. those are some spectacular links on optics, googling this subject was exceptionally difficult

ive got these LEDs and these sensors, the sensors i specially bought because they could be potentially flush mounted in foam, the shielded square bit is about 4mm thick. i need to order some RGB strips, and some lenses.

I just realized, are you planning on laying the IR sensors right in the foam so they are on the exterior surface? That sounds awesome from a coverage perspective. There may be logistical challenges though. How are you thinking about wiring them? How many were you thinking of using? The typical domes usually have 3 sensors and give good coverage for a 180+ degree arc. Putting one on the top/bottom gives you pretty much full coverage except for obstructions like the tail, prop, fuselage and other bits. I would expect it would be reliable enough that with the ambiguity in the aiming it won't be noticeable. Putting them on each surface gets you around all those obstructions but you need to wire each one. Basically the pins for each IR receiver are wired together and power/ground go through a cap and resistor. I don't know actually how many receivers you can put on the same cap/resistor. I have only tried 3. If you spread them out you will need somewhere to place those components and might need multiple sets. I would love to see this! I am not good at keeping everything neat and tidy in my planes. The inside is usually just a wad of painters tape that I shove in after everything else to keep stuff from flying. Ask me how many times I have ejected my ballast because the tape gave way on landing .

For those IR LEDs, did you find a lens that will work? The 3d printed part is 50mm but it can be remade pretty easily.

 

[Duck]

Nanos are incredibly versatile and inexpensive. But before you order some...

If you want something extremely powerful, inexpensive and programmable with the Arduino libraries, look at the ESP32 platform.
- dual core, simple to control and send tasks to each core
- more RAM and flash than you will ever need and a ridiculous clock rate for an embedded device
- low power consumption
- wifi and bluetooth onboard
- tons of ADC/DAC/PWM pins
- capacitive touch sensing on most GPIOs
- ten frickin' dollars mounted on a board with power supply etc! Sometimes even with an OLED display, radios or more!

You can take your Arduino program and compile it directly for ESP32 or the ESP8266 (its older and now obsolete brother, single core, less IO).
If you're getting into microcontrollers and building your own PCBs these are definitely worth looking at.

I had looked at them but they have a number of issues that prevent them working as is. The main ones are the operating voltage being 3v instead of 5v and the fact that the IR library I use explicitly says it doesn't work on that board. I know you can work around that but I wanted fewer issues. I bought a nano every to try it out. As expected, it does have a couple issues with the libraries I use. Both the PWM input library and the IR library don't support it out of the box. It looks like the IR library is actually hosted on GitHub now and has multiple board variants. Nano Every isn't in the list yet but someone has a proposed patch. It won't even compile as it. Until I get all the features working, I wouldn't make a PCB. The issue is that depending on the platform, you might need to change the pins as different pins have different interrupt, timer and PWM support depending on exactly which platform you use. I will keep plugging away on getting it to work but I don't expect it to be fast. There are a bunch of things about how arduino is ported to platforms that are not clear to me and a better understanding is going to be critical to getting it working.

 

[evranch]

If you buy an ESP32 that is on a board like the NodeMCU, they have a low dropout regulator onboard that can handle 5v (I think up to 7-8v but not 12). This is how they run off the USB power supply, and they have a Vin pin that is tied to the same trace.

I usually drive all my outputs active low which lets you drop in any micro regardless of voltage. It's also pretty easy to handle input voltage differences a couple of ways:
- voltage dividers
- zener clamping (most robust)
- large input resistors, 1M+ and just using the internal clamping diodes - not many devices are actually intolerant of voltage alone, it's current that does the destroying

Porting is a bigger problem. An ESP device is more like a tiny computer than traditional Arduino microcontrollers.

The thing about the ESP series is that when you run Arduino code on them it's actually running on their internal RTOS as a process - this can mess up timings when you are trying to bit bang things such as IR and it switches threads. ESPs will switch threads any time you call delay() which really messed me up when I first started using them - in fact, to have the built-in wireless libraries work properly on an ESP8266 you have to regularly call delay() in your main loop so that it has some time to work. I would guess this is the reason that the PWM/IR libraries don't support it.

Once you get used to it you start using the multithreaded RTOS all the time for handling things that used to require counting millis() or using interrupts. For example a 1 second slow PWM output for a heater can just run in its own thread, reading a global and sleeping with delay() between state changes. So easy!

ESP32 has its own hardware support for IR communications, though I've never looked into it. It probably just handles some standard protocols or is a UART in disguise.

There is a way to lock a process to a specific core at realtime priority, xTaskCreatePinnedToCore. This is where the ESP32 shines over the ESP8266, because you can set one core to run a single thread in realtime doing your bit bangs while the other stuff gets scheduled on the second core. You can pass values back and forth through global variables. So you never have to worry about finding time in your loops for running serial I/O, wireless or other slow logic. I suspect this would be the way to get the IR protocol to work on these units.