USB2FIR - USB visual thermometer with MLX90640

USB2FIR is a interface board to connect the far infrared thermal sensor array MLX90640 via USB to a host system.

Full access to MLX90640 memory (EEPROM, IR data) over USB control transfer
Bulk-transfer mode for fast infrared data transmission
Raw sensor data, calculation of pixel temperatures by host
Firmware sources available; bootloader for firmware updates
Open source Python library

Software

Drivers

USB2FIR can be accessed with libusb. On Linux and MacOS X no kernel driver is needed. Windows requires a driver for USB2FIR. Please use this tool for Windows to install the "WinUSB" driver:

Zadig - USB driver installation made easy

Depending on the application, under Windows a libusb-1.0.dll is required. These can be found for various architectures on the libusb project homepage under "Download -> Windows Binaries". Please place the DLL in the application folder.

pyUSB2FIR - Python library

from pyusb2fir import USB2FIR

u2f = USB2FIR()
frame = u2f.initializeFrame()

for x in range(2):

    # read a subframe, calculate temperatures
    # and store the resulting half frame in 'frame'
    u2f.updateFrame(frame)

    print frame

The library fetches the IR data from the USB2FIR and calculates the pixel temperatures.

pyUSB2FIR source code on GitHub

GUI based on Matplotlib and pyUSB2FIR

With Matplotlib the frame data calculated by pyUSB2FIR can be visualized and stored as png-file.

view_matplot.py source code on GitHub

GUI based on TKinter and pyUSB2FIR

TKinter GUI showing real time heat map, minimum, maximum and center temperature.
The screenshot shows the thermal measurement of a solder iron tip, running on Windows 10.

view_tk.py source code on GitHub

Firmware

Source code and HEX file

The firmware of USB2FIR is available as precompiled HEX file and as C (XC8 compiler) source code.

Precompiled HEX and source code archive:

usb2fir_firmware_v1.0.zip (2018-07-10) First public version

Firmware update via bootloader

Start the bootloader via software (e.g. start_bootloader.py) or via hardware bridge: connect MCLR (pin 1) to GND (pin 3) on X1 and plug in USB2FIR - now the bootloader starts. Use a bootloader application (

MPHidFlash) to load the new firmware into USB2FIR:

mphidflash -w usb2fir_firmware_v1.0.hex

Hardware

Schematic - USB2FIR's circuit diagram

Partlist - Build your own USB2FIR!

Here you find a list of all parts needed to build your own USB2FIR board.

Partnumber	Value
C1, C2, C3	100n
C4, C5	4,7u
IC1	PIC16LF1455
IC2	MCP1700
IC2	MLX90640
LED1	red LED
R1, R2, R3	1k
X1	ICSP 6pol 2.54mm
X2	USB-B

Gallery

Please tell me about your USB2FIR project!

		USB2FIR EB in 3d printed enclosure. by Thomas Fischl (07/2018)
		Thermography with USB2FIR. Find and evaluate hotspots on printed circuit boards with "view_tk.py". Hotspot in this example (USB-to-serial board with load resitor) is the LDO (SOT-23). by Thomas Fischl (07/2018)

Links

Heat Mapping with a 64-Pixel Infrared Detector (AMG8833)