Overview

A temperature sensor interface board for the Raspberry Pi with 4 thermocouple inputs and 32 NTC thermistor inputs, for a total of 36 temperature sensors. Simple to use software also allows logging to a text file for later import to a spreadsheet and graphing.

Main Features

  • Four Thermocouple inputs, individually configurable for one of {K,J,N,R,S,T,E}.

  • Thirty-two NTC Thermistor inputs, 25C resistance and Beta are individually configurable allowing mixing different types of NTCs.

  • Easy to use software displays temperature of each sensor on screen and can save samples to a text file for later export into spreadsheets and graphing.

  • Audio buzzer can be enabled to beep when any of the sensors are outside of the specified temperature ranges.

  • Automatic open circuit fault detection recognizes broken wires or bad connections.

  • Stackable architecture and configurable I2C address allow the unit to coexist with other daughter cards/hats.

Block Diagram

Downloads

Datasheet
User Manual
Quick Start Guide
Linux Software   1.1   1.2   1.3

Screenshots

Software screenshot 1

Software screenshot 2

Graphing example 1

Purchasing

  • Temperature Readout Board
  • NTC thermistors(Pack of 4)
  • Mounting Hardware(fem/fem standoffs x 4, M2.5 screw x 8)

  • Pack of 4 NTC thermistors
  • 125C max temperature, R25=10K, Beta=3950, 1m length, compact and waterproof head
  • Part# NTC-10K-3950-WP-1M
  • Datasheet

 

  • Pack of 2 K-Thermocouples
  •  400C max temperature, 1m length
  • Part# K-THRM-1M
  • Datasheet

  • Stacking hardware to connect multiple temperature readout boards
  • 4 x male/female extra tall m2.5 standoffs
  • 20x2 male female stacking connector
  • Part# RPI-STK-KIT-1

 

FAQ

Which versions of the Raspberry Pi are supported ?

PI 1 Model A+, PI 1 Model B+, PI 2, Pi Zero, PI 3, Pi 4.

Can I use my own NTCs ?

The NTC parameters are all configurable inside the .conf file, any NTC with a 25C resistance between 1K and 100K can be used.

I don’t know the parameters of my NTC ?

NTC parameters like 25C resistance and the beta constant can usually be found inside the datasheet. Another option is to manually measure the resistance of the NTC at two different temperatures and then calculate the beta constant. Please see the -ntc_calc_beta command description in the user manual.

I’m not sure which thermocouple wire is + and which is - ?

The red wire usually corresponds to +. If you’re unsure just hold the thermocouple with your fingers and verify that the temperature reading spikes up compared to ambient. If it doesn’t look correct then switch the wires around and repeat.

Can I stack multiple boards one on top of the other ?

Yes, multiple boards can be stacked one on top of the other to increase the total number of sensors. Additional information can be found in the “Stacking Multiple Boards” section of the user manual.

How do I graph the results ?

The contents of the log file can be copy/pasted into any spreadsheet, please select comma delimiting when pasting. A scatter line graph works well for displaying data from multiple sensors.