This isn't exactly a build thread, it's more of a mod thread. The actual quad used has changed once already. I'm a noob when it comes to quads and I hope to get some tips and tricks.

The aim is to use a quad to film and poke around in old abandoned mines. I posted a little about this in my intro thread and included a video clip from one of my adventures here: https://intofpv.com/t-hi-from-sweden-loo...fect-drone

So I'm putting together a quad with a lighting system for this purpose. I've read some suggestions about IR. Yes, IR would be better for poking around but I want to use the footage for small clips and I simply do not like IR footage.

The first quad I used was my GEPRC Crocodile5 Baby. I put on a dual XM-L2 LED headlamp with spot and flood, chopped of the cable and hooked it up with an old dual channel LED driver I designed a few years ago for a similar headlamp. I hooked the driver up to the FC and used PINIO function to control the LEDs individually with AUX switches (flood, spot, both). Each LED was driven to just over 1 amp and powered by a small 1S LiPo taped to the bottom. 1 amp is not much but was good enough for initial testing.





First clip is from a chamber. Caddx Peanut footage was rather useless, this is recorded in DJI goggles. I had the DJI camera on at the time, it has since this video been replaced with the Caddx Polar.



Second clip is the small tunnel. Footage is from Caddx Peanut processed with Gyroscope default settings.



One thing I found out quickly is that I don't have the nerves to use such an expensive quad as a tunnel rat. I bought it new and I like it too much to use in dirty old mines. Maybe open air chambers with natural  light where it can be retrieved if I crash, much like the mine in that clip I posted in my intro thread (providing the winter has been cold enough so the ice is solid enough to walk on).

So, may I present Tunnel Rat II. A Diatone Mxc Taycan 369 I bought second hand. It has a DJI Air Unit and Crossfire RX, and with it I got 2 sets of extra props and 5 somewhat used but working 4S 1300mAh LiPos. I got all that for about $180, cheaper than a new DJI Air Unit so I couldn't resist. I traded the DJI camera for a Caddx Polar and slapped on some beefier lighting



The LEDs are both the beefy MT-G2s installed in heads from Convoy S3 flashlight hosts.



Once again I used an old flashlight driver board I had designed. I couldn't be bothered with adding the old obsolete microprocessor and programming it so I just soldered on wires for PINIO and everything else. I put in connectors so I can easily remove the lighting system without opening the quad. The driver has 4 CAT4104 regulators which drive the two 6 volt MT-G2s in series at 1 amp or 4 amps. It's not a very efficient way of driving LEDs, ultimately I want to use a current controlled buck/step down driver but I don't currently have any, I took what I had to get it into the air.



I took it out for a test flight around a local forest in the darkness. It stuggles with the added uneven weight and flies a bit wobbly. I found the dual MT-G2s in these shallow Convoy S3 heads to be way to floody. Here is a short clip of that test flight filmed with Caddx Peanut in auto mode. First half is with 1amp, half way though I switch on full 4 amps. Sorry all for the noob flying, it's not the skilled piloting normally seen in videos here.



After that flight I removed those flashlight heads. I'm putting together another test with the same driver but different LEDs. 3 XP-L HI with Carclo triple lens for spot, and a single 3V XHP50.2 with wide TIR lens for flood. This time no heavy flashlight heads so I should shave off some weight.

Well the first thing that strikes is, is this outdoor night flight in compliance with EASA rules, one for you to ponder, not for discussion.

The second thing is that by brightly lighting a narrow area, the Polar Starlight camera is likely hampered in resolving the wider view needed for safer operation.

I suggest you try a test of the camera under moonlight conditions without extra lighting on. I have a Polar equipped quad and its pretty good, but then I'm remote urban so some low sky illumination.

Damn that night flight is pretty seat of your pants level. But flying at night is probably the easiest way to simulate conditions underground in a safer environment.

(15-Oct-2022, 03:05 PM)Bad Raven Wrote: Well the first thing that strikes is, is this outdoor night flight in compliance with EASA rules, one for you to ponder, not for discussion.

Correct.... but it wasn't me... I stole this footage from some site on the web and the source has apparently been removed... All this is just fiction...

(15-Oct-2022, 03:05 PM)Bad Raven Wrote: The second thing is that by brightly lighting a narrow area, the Polar Starlight camera is likely hampered in resolving the wider view needed for safer operation.

I found it to be the other way around. By having too brightly flooded area close up, the camera adjusts brightness and what's further in front is darkened out. I need to dampen the flood and increase the spot, get a more even spread of light. The MT-G2s are not optimal so I am putting others on. The footage above is from a Caddx Peanut, the view in the goggles with the Polar was slightly better overall but more sensitive to close proximity brightness.

(15-Oct-2022, 03:05 PM)Bad Raven Wrote: I suggest you try a test of the camera under moonlight conditions without extra lighting on.  I have a Polar equipped quad and its pretty good, but then I'm remote urban so some low sky illumination.

I have flown in low light conditions with the Polar, I think it's awesome. Sometimes I get shocked at how dark really it is when I take of the goggles. However, this test was to simulate flying underground with absolutely no ambient light at all to see how the LEDs perform.

(15-Oct-2022, 08:49 PM)Pathfinder075 Wrote: Damn that night flight is pretty seat of your pants level.  But flying at night is probably the easiest way to simulate conditions underground in a safer environment.

Yes, getting underground is not something I can just go out and do, so at least flying around trees can give me in idea of how the lights perform. Aiming for a proper field test next weekend.

You may find something helpful in this post.
https://intofpv.com/t-trying-out-some-of...t+led+test

(15-Oct-2022, 10:46 PM)brettbrandon Wrote: You may find something helpful in this post.
https://intofpv.com/t-trying-out-some-of...t+led+test

Thanks, nice to read on someone doing similar things. I see that ph2t opted for a combo of 20 degree spot and 100 degree flood which is similar to what I'm setting up now, and not unlike the headlamp I used on the crocodile 5.

I am using constant current regulator linear (not buck / step-down) regulators on 4S so I have to use a combination of LEDs in series to get a forward voltage of about 12 volts. Ordering this kind of stuff to Sweden takes ages so for now I'm only using what I have laying around. So instead of those two 6 volt MT-G2s I'm going to slap on a triple MCPCB with XP-L HI LEDs and use Carclo's narrowest triple optics 10507 on it for spot. For the flood I'll use a 3V XHP50.2 with some random frosted TIR lens I have had laying around for ages but never used. If it's not floody enough I have some D-C-fix diffusion film to put on.



Now I just have to figure out a way of mounting it to the quad. I've got some specific heatsinks that happen to be easily mounted, and I could JB-weld the LED MCPCBs to the heatsinks but I only have one set of heatsinks. JB-weld will make those LED MCPCBs stick permanently to the heatsinks, I might want to change them in the future but keep the heatsink mounts.... so I have a little head scratching to do.

Is it too hot for liberal use of velcro?

(16-Oct-2022, 01:36 AM)Pathfinder075 Wrote: Is it too hot for liberal use of velcro?

Of coarse velcro would be handy but I'd like to use the heatsinks as heatsinks so I want the back of the LED MCPCBs to be on the heatsinks. I'd rather go with electrical tape, I've used quite a lot of that stuff as can be seen in my photos

Thermal heat pads, like the ones you find on cheap CPU heatsinks, might work. They are removable, by warming the heatsink and gently twisting it back and forth until it comes off.

https://www.3m.com/3M/en_US/p/d/b00051394/

(16-Oct-2022, 03:03 AM)Pathfinder075 Wrote: Thermal heat pads, like the ones you find on cheap CPU heatsinks, might work.  They are removable, by warming the heatsink and gently twisting it back and forth until it comes off.

https://www.3m.com/3M/en_US/p/d/b00051394/

Not a bad idea at all, I didn't think of that. I'll see if I can source some locally. In the meantime I have found replacement heatsink alternatives so I went ahead and used a little JB weld on the edges. Hopefully I can get the LEDs off the heatsink so I can re-use them for other stuff if they get replaced. Now just waiting for that stuff to harden.

New lighting system is on. Optics attached to LED MCPCB with JB-weld, likewise the LED MCPCBs to the heatsinks. I drilled holes in the heatsinks to line up with frame screws so it can easily be removed and re-attached.



I tidied up the driver cables and added connectors to LEDs instead of direct soldering, it'll make LED swapping a lot easier.



During the week I'll head out to the same forest field and do a test run. Hopefully it'll be ready to rumble next weekend.

Hey Mike, great stuff mate!   I like how you came to the same considerations as I did.

• Flying outside in the clear is useless unless you have crazy powered lights, need to reflect to see.
  
• Light source always behind the camera, without any reflections off any surface of the quad that is in front of the lights and camera - IE: props!  They light up like light sabers with LED lights reflecting off them at night.
  
• Any local reflections will screw with the camera's dynamic range for the area you actually want to see, you don't want this.
  
• Most intense light right in front of you, you are going forward by design
  
• Less intense light at your periphery, again you want to maximize the reflections of adjacent objects, 
  
• A single lens based light source can't do both well - limitations on size, power, weight and heat dissipation drive a multi led / multi focus solution.
  

I like how you added some functionality using an extra control channel.  I'm revisiting my night flight with a digital version since converting my fleet from analog.   Think it will look awesome.   I'll be using a LED driver integrated with PWM control that I'm going to try and connect up to one of the variable pot dials on my TX.  Going for the ability to change brightness, switch on/off sorta function.

following with interest!

Cheers,

ph2t,

Thanks! I'm interested in your thread too. I hope you keep it updated with your progress. With those LEDs you have achieved a very nice balance of flood and spot.

I have designed a few flashlight drivers in my time and was planing to use one to have brightness ramping controlled by AUX switch, but for now I'll just settle with OFF, LOW and HIGH. What I do want is a current controlled buck/step-down driver so I don't have to run different LED combinations to get up to 4S voltages. So far I've only designed current controlled linear and boost drivers, I don't know if I'll bother with designing my own buck driver so I'm searching for some existing driver that might work.

I am concerned about that frosted TIR optics on my flooder LED. It is sticking out in front of the camera lens and it doesn't seem to be floody enough on bench testing. I think your LED solution for flood is much better and from what I can see in the specs of the optics you use, the inner diameter of those optics is just under 8mm. That's fairly large, can you confirm it? If so it could be a direct replacement for the crappy optics I have on my current flooder LED.

I was interested to see how the signal range would work when poking around in tunnels that are not in line of sight. I've read of people saying it won't work but not seen any practical evidence of that so I went for a few test runs in an old abandoned railroad tunnel with the aim of pushing it until I got signal loss.

On the goggles I had two patch antennas, two stubbies and DJI transmission power set at 1000mW. The video signal did hover around 1.5Mbps at one end of the tunnel, briefly dropping to 0.9Mbps. I don't think that's bad considering where I was sitting and the direction I was facing (can see me at the end of the clip). I didn't need the lights in this shallow tunnel but did a quick test with them. I think they will be fine for environments like this.



With four stubbies I always lost the signal resulting in some really bad landings (crashes) if I was sitting on top of the tunnel. The frame is now pretty beat up and cracked but I bought it cheap and had to do some testing before dragging a full FPV kit down into some abandoned mine (much more of an expedition). The only thing I really care about on it is the Air Unit. Now I just need a new frame...

Someone suggested getting a Veyron30CR as a direct replacement for the Taycan frame in terms of motor and FC mounting patterns so I went ahead and ordered one. It arrived and I've now done the transplant. The Taycan weighed in at 286 grams, with the new frame I did not want to exceed that.

First I put it together as you are supposed to with the DJI Air unit. A few grams lighter so my weight requirements have been met.



It's obviously a frame for an analog build and it appears they didn't want to re-design it for the Air Unit so they came up with this TPU print to mount the Air Uni on it's side. Sure it fits but I absolutely hate that because it pushes the batteries I use forward and causes it to be far too font heavy. I think this frame is more suitable for a Vista, it could probably fit over the FC without modifications but I don't know that for sure, I didn't want to have to order a Vista.

So I did the only sensible thing left to do. I tore it apart, got rid of that silly TPU for side mount, carved out a little in the frame and stripped the Air Unit naked. Now everything is much more centered with the added benefit of being a little lighter.



I decided to test other LEDs on this build so I went with a 12 volt XHP35-HI LED and TIR lens. These LEDs are sensitive and can't be over-driven much so I replaced the driver from the previous build with 3 old 700mA drivers, giving a total of 2.1 amps which is the sweet spot for this LED.



After a short test flight I can say that I certainly like this LED as the spot light, the dome-less HI LEDs are perfect for this. I will be adding some flood LEDS later but I need to wait for the dedicated dual LED channel driver PCB I designed for this purpose. Then I will have separate current control for each LED channel. so the lighting will be improved, but in the meantime this will do fine.
So without further ado, allow me to present Tunnel Rat III.



I took it for a test flight and the LED is great but the quad itself sometimes twitches heavily at the end of a flip or roll. It doesn't bother me too much, as a tunnel rat it's not going to be doing flippy flops, but I would like to know what it could be. This didn't happen when everything was on the Taycan frame, and I have not made any changes to any software since moving over to the new frame. Anyone got any suggestions?