DIY Thermal Camera

This is a simple thermal camera that can be built using off-the-shelf parts from Adafruit (albeit with a long lead time due to component shortages).

Reddit post about it

BOM

Adafruit 1.3" PiTFT Bonnet
Raspberry Pi Zero W
- You'll want with headers if you don't have any you can solder yourself
MLX90640 IR Thermal Camera
MicroSD card
StemmaQT cable

Features

Auto-start at boot
- This software runs on a Raspberry Pi Zero W, as a result it needs to boot. When it boots, it automatically starts up via systemd
Freeze frame
- Pause capturing to examine the current frame, all view settings can be manipulated to look at individual pixel temperatures, adjust corrections, scales, etc.
Capture to PNG
- Saves images to ~pi/thermal-images
MTP support for transferring images
- Exposes ~pi/thermal-images over MTP for Windows, macOS (Android File Transfer) and Linux machines
Selectable temperature ranges
- Available temperature ranges are: auto-range (min, max), outdoor body detection (10-32C), indoor body detection (20-32C), hot spot identification (20-50C), and extremes (-10 - 200C)
Switchable C/F temperature scale
Adjustable emissivity correction
- Adjustable from 0.05 to 1.00 in 0.05 increments. Default at 0.95
Movable reticle showing temperature under the crosshairs
Four lockable reticle points for indicating temperature
- Temperature at 7 points can be tracked in real time: under the reticle, at the four locked reticle points, and the min and max points
Switchable color range (Gnuplot PM3D, and a basic rainbow)
Display of estimated ambient temparture
- This can be warmer than ambient, depending on the temperature of the Pi inside the case.

Controls

Hold A (left button) and then B (right) together at the same time to exit
Hold B and then A together at the same time to change the scale palette to PM3D or rainbow
Press A by itself to freeze-frame, press again to release freeze-frame
Press B by itself to toggle the temperature units between C and F
Press U(p), L(eft), R(ight), D(own) by themselves to move the center reticle
Hold B and press U to adjust emissivity correction up by 0.05
Hold B and press D to adjust emissivity correction down by 0.05
Hold B and press L or R to scroll through temperature ranges
Press C(enter) by itself to lock a reticle location for temperature readout
Hold B and press C to clear all selected reticle locations
Hold A and press C to save the current screen to disk as PNG

Instructions

This solution involves installing software from raspbian packages, python3 packages using venv and pip, and some locally compiled components uMTP-Responder

In addition to software, there is minimal hardware assembly and 3D printed parts.

Software

$ sudo apt install python3-venv
$ python3 -m venv --system-site-packages ~/src/thermal-imaging
$ cd ~/src && git clone https://github.com/pfn/thermal-camera thermal-imaging
$ cd ~/src/thermal-imaging/bin
$ ./pip install ST7789
$ ./pip install mlx90640-driver
$ ./pip install mlx90640-driver-devicetree
$ ./pip install colour
$ ./pip install pillow
$ ./pip install RPi.GPIO
$ sudo mkdir /etc/umtprd
$ sudo cp ../conf/umtprd.conf /etc/umtprd/
$ sudo cp ../conf/thermal-camera.service /etc/systemd/system/
$ sudo cp ../conf/umtp-responder.service /etc/systemd/system/
$ ln -s armv7l ../lib/python3.7/site-packages/mlx90640/libs/armv6l
$ ln -s armv7l ../lib/python3.7/site-packages/mlx90640_devicetree/libs/armv6l
$ cd ~/src && git clone https://github.com/viveris/uMTP-Responder
$ cd uMTP-Responder && make
Add dtoverlay=dwc2 to the bottom of /boot/config.txt
$ sudo systemctl enable thermal-camera
$ sudo systemctl enable umtp-responder
Reboot the Pi

For any missing packages, sudo apt install them as appropriate.

Hardware

Print 2x of the buttons, 4x of the spacers, the top and bottom of the case.

Solder headers onto the Pi if necessary.

Attach the StemmaQT cable to the camera and TFT bonnet.

Place the Pi into the bottom of the case. And place the 4 spacers onto the nubs that protrude through the Pi.

Press the TFT bonnet down into place onto the Pi.

Position the camera on the bottom of the case and place the lens through the hole.

Put the top of the case onto a flat surface, and put the buttons into the button holes.

Run a bead of super glue around the edges and press the case together.

All done!

pfn / thermal-camera