Pi-SPi-8AI Raspberry Pi Analog Input 4-20 mA Module

Pi-SPi-8AI Raspberry Pi Analog Input (4 - 20 mA) Interface

Regular price $24.95 Sale

The all new analog input interface for the Raspberry Pi is here! The Pi-SPi-8AI is based on the popular VP-EC-8AI 8 channel 4-20 mA input module, and the Microchip MCP3208 12 bit A/D converter.

The 26 pin GPIO port is duplicated on either side of the module, so more modules can be "daisy chained" together.

 Node-Red support is now available.

There are three standard versions of analog inputs available:

Inputs 1 thru 8 are 4-20 mA (Load Resistor 150 Ohms)

Inputs 1 thru 4 are 4-20 mA Input (load Resistor 150 Ohms)
Inputs 5 thru 8 are 0 to 6.6 VDC Input

Inputs 1 thru 8 are 10K Thermistor Inputs
for Temperature Sensor Applications

Each channel can be configured as either mA or Voltage. Another feature is all inputs can easily be configured for thermistor input making the Pi-SPi-8AI an 8 channel temperature sensor module.

GPIO Port Pins Used:

CS_8AI     (GPIO7)


  • Identical foot print to the RPi 3
  • Separate field power input (9-24VDC) for remote transmitters
  • Each module has its own 3.3VDC LDO regulator operating from the RPi 5VDC bus
  • No loading on the RPi 3.3VDC bus
  • Terminal Blocks for analog input signals
  • LED indicators for power
  • Dual 26 pin GPIO connectors (left and right)
  • MCP3208 A/D Converter with 12 bit resolution
  • Each analog signal buffered (1/4 LM324 Op Amp)
  • Inputs 1 thru 4 are configured for 4 to 20 mA Input (Standard)
  • Inputs 5 thru 8 are configured for 0 to 6.6 VDC Input (Standard)
  • All inputs can be configured for either mA, VDC, or Thermistor Input for temperature measurement

Other input configurations are available, please contact us before ordering!

Pi-SPi-8AI Accessories :

  • Pi-SPi-PS-24VDC Field Power Supply
  • Pi-SPi-CABLE-40x26-2 (40 Pin to 26 Pin x 2")
  • Pi-SPi-CABLE-40x40-2 (40 Pin to 40 Pin x 2")
  • Pi-SPi-CABLE-26x26-2 (26 Pin to 26 Pin x 2")
  • Pi-SPi-MTG-HDW Mounting hardware 4x1/2" Aluminum spaces c/w 8 x 4-40 Stainless Steel Screws

NOTE: All Accessories sold Separately

For 4-20mA transmitter descriptions and connections, please visit:

4-20 mA Current Loop



PCB Layout

Sample Software (Python)

Please download the latest Widgetlords libwidgetlords library. The instructions can be found at

Getting Started with PI-SPI Libraries

All of the sample code examples are based on the latest library installation. Please note the code samples all use Python 3.

Basic Python "Read" A/D Counts Program:

from time import sleep
from widgetlords.pi_spi import *

inputs = Mod8AI()

while True:


The PI-SPI-8AI sample code programs and instructions can be found at

PI-SPI-8AI Python Code Samples

A complete set of Python demo code examples for the PI-SPI and PI-SPI-DIN series can be found on our GitHub repository: