Precision PT100 Temperature Reading Made Easy

The Adafruit PT100 RTD Temperature Sensor Amplifier - MAX31865 is a high-accuracy breakout designed for reading PT100 platinum RTD sensors with your microcontroller. If your project needs more stable and repeatable temperature measurements than many common thermistors or basic temperature sensors, this board gives you a more reliable way to capture precise readings.

Built around the MAX31865, this breakout handles the low-resistance measurement requirements of PT100 sensors and supports 2-wire, 3-wire, and 4-wire RTDs. It communicates over SPI, making it a strong choice for Arduino, ESP32, Raspberry Pi Pico, and other SPI-capable development boards.

Important: This breakout is for PT100 RTD sensors. The sensor probe itself is not included. If you need the PT1000 version, use the dedicated PT1000 MAX31865 board instead.

Why you'll love it

Designed for PT100 RTDs for accurate and stable temperature measurement
Supports 2, 3, and 4-wire sensors for flexible wiring options
MAX31865 amplifier onboard to simplify RTD interfacing
SPI interface for easy integration with many microcontrollers
5V compliant design with onboard 3.3V regulator and level shifting
Compact breakout for breadboards, prototypes, and embedded builds

What you can build

This board is ideal for precision temperature logging, lab and test setups, process monitoring, environmental sensing, incubators, heated enclosures, food temperature experiments, and any project where RTD-level measurement quality matters.

Starter bundles

Pair this breakout with a PT100 RTD sensor, an Arduino-compatible board, ESP32, or Raspberry Pi Pico, plus jumper wires and a breadboard for fast prototyping.

Recommended add-ons

For cleaner builds, add terminal wires, screw terminal accessories, or an enclosure. You can also pair it with OLED displays or LCD modules if you want a live local temperature readout.

Technical specifications

Product Name	Adafruit PT100 RTD Temperature Sensor Amplifier - MAX31865
Amplifier IC	MAX31865
Sensor Compatibility	PT100 RTD
Supported Wiring	2-wire, 3-wire, and 4-wire RTD sensors
Interface	SPI
Reference Resistor	430 Ω, 0.1%
Logic Compatibility	5V compliant with onboard 3.3V regulator and level shifting
Product Dimensions	28.0mm × 25.5mm × 3.0mm
Product Weight	2.7g
Assembly Notes	Current revision includes terminal blocks already soldered in place

Pinout & power notes

The board connects to your controller using SPI, and the RTD sensor connects through the onboard terminal block. Since the breakout includes regulation and level shifting, it is easier to use in both 3.3V and 5V systems.

For best results, use the correct RTD wiring mode in your code and match the board to a PT100 sensor, not a PT1000.

What’s in the box

1 × Adafruit PT100 RTD Temperature Sensor Amplifier - MAX31865 breakout board

Note: PT100 RTD sensor probe is not included.

Frequently Asked Questions

Does this include the PT100 sensor? No. This product includes the amplifier breakout board only. The PT100 RTD sensor must be purchased separately.

Can I use this with Arduino? Yes. It uses SPI and is 5V compliant, so it works well with Arduino and many other microcontrollers.

Can this work with 3-wire or 4-wire RTDs? Yes. The MAX31865 supports 2-wire, 3-wire, and 4-wire PT100 RTD configurations.

Is this the same as the PT1000 version? No. This board is specifically configured for PT100 sensors. PT1000 uses a different reference resistor and requires the PT1000 version.

Why use a PT100 RTD? PT100 RTDs are known for excellent stability, repeatability, and precision, especially in applications where accurate temperature readings matter.