This project is designed to be a 10-channel temperature logger based on 10k NTC thermistors.

I designed the board with JST connectors, so it is easy to connect the thermistors to the board. It is easy to find NTC thermistor probes with JST connectors.

The board is designed to accept a STM32F401CCU6 microcontroller board. It is a relatively cheap microcontroller, but it is super powerful. Therefore, it will be able to read all 10 channels quickly while also showing the measurements on a display and saving the data on an SD card. It is also convenient that this microcontroller comes with a USB-C connector. It is sturdy and easy to connect.

The display is a generic 1.8" TFT LCD with SD card slot.

I picked relatively large SMD components, so it is easy to hand-solder them. Just use a lot of flux, and a pointy soldering iron, and be patient.

The board has additional "breakout pins". They are marked as "REF**" in the interactive BOM because I did not associate them with any component. The user can decide if a pin, a socket or a wire should go to the corresponding connections. I used pins in my version.

The board also has two test pads next to the voltage reference: VREF 3.3 and GND. I put them on the board so one can quickly check the real value of the supply voltage of the NTC thermistors.

Please watch my video and visit my website for more information. I wrote a very detailed code for the microcontroller.

Update (2023-07-20):

I added a new video link and a link to my website where I show and explain some improvements made to this system.

• I created a new, better GUI
• Added more intelligent file management for the log files
• Updated some calculations so the user can have individual R2 resistors for all 10 channels
• Replaced some of the R2 resistors in the voltage dividers to have better linearity in the low-temperature region
• Made a new 3d-printable front panel