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.
There are three standard versions of analog inputs available:
PI-SPI-8AI-8MA:Inputs 1 thru 8 are 4-20 mA (Load Resistor 150 Ohms)
PI-SPI-8AI-4MA-4VDC: Inputs 1 thru 4 are 4-20 mA Input (load Resistor 150 Ohms)Inputs 5 thru 8 are 0 to 6.6 VDC Input
PI-SPI-8AI-TEMP :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:
SPI-MOSI (GPIO10)SPI-MISO (GPIO9) SPI-SCK (GPIO11)CS_8AI (GPIO7)
Other input configurations are available, please contact us before ordering!
For 4-20mA transmitter descriptions and connections, please visit:
4-20 mA Current Loop
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 sleepfrom widgetlords.pi_spi import *init()inputs = Mod8AI()while True: print(inputs.read_single(0)) sleep(0.5)
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: