Tc Logger Device

TC Logger Device is a simple thermocouple USB reader: help you to measure any proccess you need using the USB protocol an a simple software developed in Python. From the oven while you are cooking some amazing Pi pie or creamy piece of meat, to measure the temperature curve of a reflow oven or a industrial process. The project is able to use two thermocouple at the same time and share the data to the computer at a speed of 5Hz. (5 samples per second). The main microprocessor is the PIC18F14K50.

Github Repository

You will need the following components: (For revision v1.2b)

• 1x - U1 - PIC18F14K50-I/SS
• 2x - LED1,LED2 - Green LED 0805
• 2x - R2,R3 - 220 Ohm 125mW 0805 resistor
• 4x - R1,R4,R5,R6 - 10k Ohm 125mW 0805 resistor
• 5x - C1, C2, C3, C7, C8 - 100nF 50V 0805 Capacitor
• 2x - C5, C6 - 22pF 50V 0805 Capacitor
• 1x - C4 - 470nF 25V 0805 Capacitor
• 3x - D1, D2, D3 - 70V Schottky diode
• 1x - J2 - Molex SMT CH0.58 16Ckt Type C
• 1x - J1 - Screw Terminal 3.5mm 4 position
• 1x - IC1 - TC1108-3.3VDBTR
• 1x - Y1 - 8pF 12MHZ / 2x2.5mm Crystal
• 4x - FB1, FB2, FB3, FB4 - Ferrite Bead 0805
• 2x - IC2, IC3 - Maxim 31855 Type K

Here you have the attached BOM that I shared with PCBWAY so they could assembly all the board. You will find all the components, metrics, and reference numbers.

The pic18LF14k50 communicates with both MAX31855 using SPI communication. There is a first problem here: The PIC18F is working at 5V (so the USB communication is easier), but the MAXIM ICs works at 3.3V. For that reason, we have a really simple level shifter using a couple of diodes.

In adddition, we have USB communication with a PC using the internal USB Compliant circuity of the PIC. On top of that, we need to use an external 12Mhz clock to multiplex it for USB communication.

Finally, we have some ferrite beads in series with the thermocouples lines and screw terminals to help avoiding noise in the ADC chip, so the readings f temperature are even more accurate.

However, I didn't include any battery or SD card for the logger, so it cannot operate autonomously. It should be connected to a PC at all times.

Solder paste can be applied with a syringe or stecil. Afterwars, the SMD components must be placed with the use of some tweezers. It can be soldered in a hotplate or using a heatgun.

For the only TH component (4-pos screw terminal), you should use a soldering iron with some tin.

You will need a Tag-Connect 6-pins cable for the ICSP on the board. You will find the code here:

https://github.com/makingdevices/TC-Logger-Device/tree/main/Firmware_HEX/1.50

Or from the attached file. You should use MPLAB and C18++

Once the board is programmed and ready, you will also need the software to the pc, which you will find here:

https://github.com/makingdevices/TC-Logger-Device/tree/main/PC%20Software

You will also find the manual and instructions attached.

You can develop your very own program using the SCPI commands listed on the GitHub Repository

First of all, if you like my projects, I strongly recommend you to follow us on our Instagram profile, Where you will be updated on a daily basis.

In addition, you have my tree-link website to check all my social media and website!

https://makingdevices.com/links/

Finally, I would like to thank PCBWAY, the sponsor of this project. I really recommend you pay them a visit if you are thinking of ordering some Gerbers at any time in the future. I am truly impressed with how good they work and the high quality of their PCBs.

Finally, if you want to support Making Devices, you can buy one TC Logger Device for yourself in the PCBWAY Bazar