This project is about building a Clip-On-Thermal-Imager (COTI) for Analog night vision goggles, similar to the Jerry-C, PAS29A/B, etc. yourself.

The current version uses a 256x192@12um sensor with a 9.1mm lens. This combined with the LZE039 and 25mm DCX lens, gives you a 1x 17°x13° thermal overlay in your NVGs.

Cropping it to a 13° circle is also an option by modifying the shape of the Display_Spacer.step model.

The unit is powered by a standard USB-C power source delivering 5v.

The BCOTI uses the Wi-Fi interface of the esp32 board to act as a web server to host a basic WebUI. To start the unit with Wi-Fi enabled,

1. hold down the push-button and then supply the unit with power, so either plug in your cable (given the poti is already enabled) or enable the poti, keep the button held down for a short moment, then let go.

2. Open your phones Wi-Fi settings and connect to "BCOTI", the password is "wifipass1234"

3. Inside a web browser, open "192.168.4.1".

4. At the top you select the active preset, so the one being both used by the unit in real time, and the one you make changes to.

5. You can either enable or disable a preset, this determines if the preset will be used, or skipped when using the push button on the unit.

6. Once you made all your changes, reboot the unit to run it on the normal mode. Then use the push button to cycle through your active presets.

• If the local webpage won't load, try disabling your mobile-data, this is an issue with some OS that won't actually try and use the Wi-Fi network because it does not provide an internet connection. On IPhone this usually isn't an issue.

• Burn protection. This will automatically close the shutter of the thermal camera if you look at something very hot, like a fire, or the sun. Note that when the unit is not powered, the shutter is in the open position, so it's highly recommended you cover the lens when the unit is not in use. Very hot object can burn the actual sensor. Burn protection has nothing to do with protecting your tube!

• Auto Shutter. This will do Non-Uniformity-Correction (NUCing) based on conditions decided by the camera (temperature mostly).

• Correct Brightness Setting. To get a good brightness setting, I'd recommend:

  1. Use the potentiometer to fully turn down the brightness of the camera.
  2. Set your display brightness one step below the step where you're able to see the shape of the display in IIT image.
  3. Raise brightness to the desired threshold.

  This may need to be done on the fly if you're environment changes, like when going from indoors, to outdoors.

• Scene mode. While the Mini2 offer many scene modes, for the BCOTI only Highlight and Outline really make sense, adjust contest as you see fit.

Expect to pay about 400€ (EU) or about 500usd (US) for parts when buying in small quantities

If you do end up buying these parts, and are happy with the end result, I'd appreciate it if you supported my future work on this and similar projects via my BuyMeACoffee page

Some of the links are affiliate links, which means I make a small commission on your purchase, at no added cost to you.

A full video guide is also available, but I'd recommend have the written instructions open as well, as any comments or changes will be made there.

• The momentary push button is now connected to GPIO8 (was GPIO21)

Using a dark material which absorbs light instead of reflecting it is highly recommend.

1. Print the Body_Shell.step, and CameraCage (The fixed-focus, or manual-focus one, depending on which one you got, Hdaniee doesn't seem to be consistent with the style of lens they ship) with a basic 0.12mm layer height profile. Change the following

   1. Wall-loops to 3x or 4x.
   2. Infill to about 22% to 35%
   3. Support to tree
   
   
   I'd recommend adding extra support to the push-button mount hole on the housing shell
   

2. Print the periscope like shown in the picture. <=0.12mm layer height, and I'd recommend "Snug" supports.

3. (Optional, but recommended) print the Bikini_Cover_TPU.step out of a fairly soft TPU. I printed mine out of 95A Overture TPU

Using Heat shrink for all connections where possible is recommended.

1. Cut the cables of the USB-C port to a length of around 80mm.
2. Cut a 1x 80mm piece of (Red) wire. And 3x 40mm pieces of (Red) Wire. These will be your 5V-net. Strip a portion of the installation on one side so that you can twist together the 3x short pieces, then cover in solder.
3. Cut 5x 40mm pieces of black wire. These will be your ground-net. Strip one side and combine the 5pieces, same as you did for the 5v-net.
4. Solder the 80mm piece of (Red) wire, to the potentiometer's on-off-switch.

5. Solder the bundle of 3 (Red) wires to the 80mm piece from the previous step.

6. Attach the 5v wires, as well as ground to the USB-C breakout board, the display driver connector, and the camera connector, as shown in the diagram.

7. Connect ground wires to the push-button, and on-off-on toggle switch.

8. Cut a 50mm piece of wire, solder one end to the push button, and the other to under side, facing inwards to the esp32c3's GPIO8 pin.

1. Insert the USB-C Port into the housing.

2. Solder the 5v wire of the Port to the on-off-switch of the potentiometer

3. Insert the potentiometer into the shell (from the inside) with the pins pointing down, and fix in place the with the Nut and washer.

4. Insert the Brightness Toggle switch (horizontal orientation), and fix in place with washer and nut.

5. With the USB-Port facing down, and the usb-c breakout connector inserted, insert the esp32 board into the centre slot of the shell

6. Disconnect the display from the driver, and insert the FPC through the hole of the slot for the display.

7. Connect the display to the driver again, then insert the driver (with the wires pointing into the shell) into the slot.

8. Insert the push-button into the slot on the bottom of the shell, and fix it in place with the nut and washer.

9. Wrap the O-Ring around the CameraCage, and insert the camera module (with the JST connector facing down, away from the slot in the top of the cage), then fix in place with all 6x M2x4 sews. Tighten them evenly, instead of doing one fully after the other.

10. Check if the camera cage can be fully inserted without putting pressure on the display FPC or any components inside the shell.

11. Insert the 11x heat inserts into the holes with your soldering iron.

12. Attach the Lens clip, Periscope, and Camera cage with the 11x M2x4 screws.

13. Attach the unit to your NV device and check the alignment of the image. (Should the image be mirrored incorrectly, adjust it via the WebUI's "Flip Mode" setting)

    1. Attach the unit like shown in the picture, so hanging straight down from your NV unit
    
    
    2. Look at a far object (20m+ ideally), and check how well the overlay lines up with the IIT image. If the image is too far in a certain direction, the camera needs to face more towards that direction; so if the image is too far left, you need to tighten the left screws (and maybe loosen the right ones). You'll need to repeat this a few times until the overlay is well enough aligned. Should there not be enough play in the camera cage to properly line up the image, you can print the camera cage with a pitch or yaw offset, 0° to 2° pitch in 0.1°-steps are available in the CAD_Files\Other_CameraCage_Offsets-folder, but usually this isn't necessary.