This Python wrapper of the Melexis MLX90640 library was written for use with the Raspberry Pi and our MLX90640 breakout. While you are free to use this software with whatever combination of device you choose, we unfortunately lack the resources to test and support any other combinations.
** Warning: ** We have reason to believe that using this library in conjunction with a Jetson Nano could damage your device, please see: pimoroni#38
** EXPERIMENTAL **
This port uses either generic Linux I2C or the bcm2835 library.
Upon building, the mode is set with the I2C_MODE property, i.e. make I2C_MODE=LINUX or make I2C_MODE=RPI. The default is LINUX, without the need for the bcm2835 library or root access.
Make sure the Linux I2C dev library is installed:
sudo apt-get install libi2c-dev
To get the best out of your sensor you should modify /boot/config.txt and change your I2C baudrate.
The fastest rate recommended for compatibility with other sensors is 400kHz. This is compatible with SMBus devices:
dtparam=i2c1_baudrate=400000
This will give you a framerate of - at most - 8FPS.
If you're just using the MLX90640 and, for example, the 1.12" OLED, you can safely use 1MHz:
dtparam=i2c1_baudrate=1000000
This will give you a framerate of - at most - 32FPS.
Now build the MLX90640 library and examples in LINUX I2C mode:
make clean
make I2C_MODE=LINUX
To use the bcm2835 library, install like so:
make bcm2835
Or, step by step:
wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.55.tar.gz
tar xvfz bcm2835-1.55.tar.gz
cd bcm2835-1.55
./configure
make
sudo make install
libav for video example:
sudo apt-get install libavutil-dev libavcodec-dev libavformat-dev
SDL2 for sdlscale example:
sudo apt install libsdl2-dev
After installing the dependencies, you can build the library. Build-modes are:
makeormake all: build the library and all dependencies. Default is to use standard linux I2C-Drivers, specify Raspberry Pi driver withmake I2C_MODE=RPImake examples: only build examples, see belowsudo make install: install libraries and headers into$PREFIX, default is/usr/local
Afterwards you can run the examples or build the python binding, see readme in the subfolder.
If you built the examples or library using the native bcm2835 I2C-Driver, you need to run all applications and examples as root.
Hence, sudo examples/<exampleame> for one of the examples listed below, or without sudo when using the standard Linux driver.
make examples/fbuf
sudo examples/fbuf
This example uses direct-to-framebuffer rendering and black-blue-green-yellow-red-purple-white false colouring.
If you gave issues with the output image, set "IMAGE_SCALE" to a smaller number.
make examples/interp
sudo examples/interp
This example uses direct-to-framebuffer rendering and black-blue-green-yellow-red-purple-white false colouring.
It also has 2x bicubic resize filter.
If you have issues with the output image, set "IMAGE_SCALE" to a smaller number.
make examples/test
sudo examples/test
This example draws out to the console using ANSI colours and the full block char.
To see the actual temperature values, change "FMT_STRING" from the block char to the float format.
make examples/step
sudo examples/step
Attempt to run in step by step mode (experimental)
Displays the MLX90640 sensor full-screen using hardware acceleration in SDL2.
Hit Spacebar to change from aspect-ratio correct to full-screen-stretched modes.
Hit Escape to exit.
make examples/sdlscale
sudo examples/sdlscale
Requires SDL2 libraries:
sudo apt install libsdl2-dev
On Raspbian Lite you may wish to build SDL2 from source with X support disabled to avoid pulling in ~200MB of dependencies. Before configuring/compiling ensure you have libudev-dev installed for input support.