MLX90640 Temperature Calibration

[pstorms]

Hello folks,

I have a situation that I need a recommendation or pointer to solve this quandary. I am looking to use 4 of these sensors to measure tyre temperatures and have the coding sorted out. But in the testing, I am finding the sensors are not capturing the right temps. And the temps between the two sensors can be up to 10C+ different and average 6C higher than expected.

I am using a teensy 4.0 and an I2C Expander

MLX Settings
mlx.setMode(MLX90640_CHESS);
mlx.setResolution(MLX90640_ADC_19BIT);
mlx.setRefreshRate(MLX90640_2_HZ);

Is there a way to calibrate the sensors so I can get consistent and accurate temperatures?

Any insight or pointers would be appreciated.

Thank you

[Disciple]

I've raised this question in another discussion, and formed a plan for my next visit to a maker's workshop. That may not happen soon due to the quarantine, but in theory I'll do the following. I shall compare sensed values to the temperatures of known surfaces. These will be various hot and cold items from around the workshop, frozen dinners and non-stick skillets and the like. I'll measure them with a commercial non contact thermometer and record the differences. With luck, the differences will be constant for each sensor, and adding simple offsets in my code will do. If the differences yield a higher-order curve, then more math is needed, but I hope no more than linear equations will be required.

This is useful as well. Calibrating Sensors ...hope this helps.

Hallelujah!
Disciple

[pstorms]

Thanks for the reply and the link. That is very helpful and I'll do some testing this week. The one problem with these MLX90640, is the pixels. My worst case fear, is a calibration of each pixel. That will be a pain. I believe there is a way to actually calibrate this sensor too. Set the offsets, but not 100% sure on this. Thus this thread.

I hope too that it will be a simple modification, benchmark, type of an approach to set the correct temperatures. I'm really wanting these can be as accurate as they state in the documentation. Looking forward to hearing your results. My whole project is based upon accuracy. It's been a battle so far. Thanks again.