We make a non-budget thermal imager with our own hands

A device based on a single-pixel non-contact temperature sensor and a mechanical scanning system, although I was very impressed, I did not repeat it, because, to be honest, its speed was not at all impressive. Modules with a microcontroller that implements the UART interface. – voltage stabilizer; The next option for the development of modules with a microcontroller are modules that implement a USB interface and which can be directly connected to a PC, while maintaining the UART interface and the I2C bus of the sensor itself is available. — USB-UART converter CH340; The PC software allows you to visualize the original thermal image from the sensor or with software interpolation. Some more sample photos One of the many arduino projects that I was fascinated with and involved in the wonderful world of microcontrollers was just a thermal imager, if you can call it that. To access the sensor via I2C, you need to close the reset capacitor (which still needs to be found). selfie taken with the AMG8833 Module dimensions 28*15 mm. MLX90640 Features: The module contains its name, version and date – “mlx_module v3.1.0 20190608. With this resolution, it is possible to use it for some practical purposes, and of course to play more seriously. Modules that include the sensor itself and its harness for powering and working with the microcontroller via the I2C bus. I tried to use software from a similar module without usb, but to no avail: apparently the communication protocols via UART are different for these modules. — Two Field of View (FoV) options: Standard (MLX90640BAB) 55°x35° and Wide (MLX90640BAA) 110°x75° The wide field of view sensor has less noise and better measurement accuracy. Unfortunately, we could not find any other information about this module other than that presented on the product page: no schematics, no software. At the same time, a com-port still appears in the system.
To find the right capacitor, I had to study the datasheet for the STM32F301K6 microcontroller and ring the board itself. – 4-pin TO39 package with required optics After all, on the same aliexpress, modules based on the MLX90640 sensor with
32*24 resolution and $60-70 price. Finally, the last option is the Red Eye Camera module, which also implements a USB interface, but, as far as I understand, there is no way to get raw data from the sensor via I2C, while UART is available.
I’ve tested a few examples of how the sensor works with the ESP32.
View from below. There are several variants of such modules: When a module with an AMG8833 sensor appeared on free sale on aliexpress, and projects using it appeared on the network, I could not resist the desire to get it, although the cost almost doubled the monthly limit allotted by me for purchases. There remains the second option for using this module – connecting directly to the sensor via the I2C bus. The capacitor connected to the reset pin of the STM32 microcontroller is highlighted in red in the photo. To work with such a module, you can do without an external microcontroller by connecting it to a PC via a USB-UART converter, I have seen 2 versions of such modules.
Of course, the resolution of the sensor is very low for any practical use as a thermal imager, but it is enough to get a lot of excitement when looking at the world for the first time “through the eyes of a predator”. — Operating temperature range from -40 to 85°C, allows for use in harsh industrial environments Disclaimer I did not lose hope that drivers for Windows would be found automatically, but the miracle did not happen. – I²C compatible digital interface for easy integration It remains to find it on the board among a dozen capacitors. — resistors and capacitors. Modules for the M5STACK / M5STICK platform, such modules contain the necessary harness to power the sensor and work with the microcontroller via the I2C bus. Such a rather expensive module was delivered in a package without any kind of protection, fortunately it was not damaged.
2.

We make a non-budget thermal imager with our own hands


I wanted to be able to interact with the sensor by
I2C, so I chose https://jiji.ng/cars/mercedes_benz-m-class-2010 module number 4, which has this feature, and also implements a USB interface. An example of saved photos from the "thermal imager". All sellers have the same photo and product description.
4. — Can measure object temperature from -40 to 300°C Obviously, in order not to use a mechanical scanning system, a higher resolution sensor is needed, I made a list of such sensors for myself, but many of them were not available for purchase. Who who has seen the movie "Predator" has not dreamed of having thermal vision as an alien hunter? Nowadays, it is not difficult, but quite expensive: not everyone can afford to buy a thermal imager, although in the last decade, with the development of technology, they have become much more affordable. Judging by the pictures on the product page, there is software for Android for this module. To do this, according to the information on the product page, it is necessary to close the reset capacitor. For the final implementation, I used the TTGO T-Watch as a control platform, which you can learn about from my reviews: one, two. — NETD as low as 0.1K RMS @ 1 Hz update rate It took quite delicate work to close it with a piece of MGTF wire. — STM32F301K6 microcontroller; But I’m more interested in modules with strapping. On subsequent connections, it was not detected at all. The sensor was purchased for $37 (now you can buy it for $28). The following components are installed on the board: With all sorts of discounts on sale on 11/11/2019, this module was purchased for $54.31. To connect the sensor to the T-Watch, I used a proto-shield for Wemos D1 mini and angled pin combs. When connected, a new unknown device with a com port appeared in the device manager, after searching for drivers, it was identified as a trackball, but the drivers were not installed correctly. 1. By the way, the MLX90614 sensor used in that project is quite expensive (in terms of cost per pixel) compared to those that will be discussed below.
After experimenting a lot with the AMG8833, I set it aside for future use and started thinking about more. — quartz resonator; But the search for this designation did not return any results. Based on this project, I remade it for TTGO T-Watch, and also added interpolation and the ability to save photos to microSD. — Typical 1° Target Temperature Accuracy, Full Scale Accuracy
Until recently, on the Internet, one could come across stories that the seller refused to send such sensors to our country, considering them to be a dual-use device.
3. The topic was supposed to be called “making a budget thermal imager”, but in the time that I did not get my hands on it, the situation changed and it became very non-budget.
About the current prices for components at the end of the article.
Separately, the sensor can before be purchased for about $55-60, depending on the version.
5. View from above. It turned out quite compact, of course, the case would not hurt.
The topic of thermal imagers captured me and I always followed the news in this area of ​​electronics with interest. — No recalibration required for specific temperature requirements, providing greater convenience and reduced operational cost

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