Knowledge Base
The AB Electronics UK Knowledge Base provides support solutions, tutorials and troubleshooting guides.
IO Pi Plus
The IO Pi Plus is a 32-channel GPIO expansion board for the Raspberry Pi and other compatible single-board computers. The board is based around two MCP23017 16-bit I/O expanders from Microchip Technology Inc, allowing you to connect up to 32 digital channels to the Raspberry Pi.
This knowledge base section contains articles and tutorials on the IO Pi Plus, showing how to use the expansion board with various input devices.
IO Pi Plus Tutorial 1 - The Blinking LED
This tutorial will start with a blinking LED and then build a binary counter using 8 LEDs. You will need your Raspberry Pi, an IO Pi Plus, 8 red LEDs and 8 500R resistors....
IO Pi Plus Tutorial 2 - Push the Button
In this tutorial, we will add a button and an LED to the IO Pi Plus and detect when the button has been pressed. You will need your Raspberry Pi, an IO Pi Plus, 1 red LED, 1 200R resistor and a push button....
Using the IO Pi with Home Assistant on the Raspberry Pi
This tutorial will setup the IO Pi Plus to use with Home Assistant Operation System on your Raspberry Pi....
IO Pi Plus Tutorial 3 - Introducing Interrupts
In the IO Pi tutorial 2, we learned how to connect a button and an LED to the IO Pi Plus and check for a button press using the read_pin() method....
IO Pi Plus Tutorial 4 - More Interrupts
In the IO Pi tutorial 3, we learned how to use an interrupt to monitor a button and turn on an LED when the button is pressed. In this tutorial, we will expand on Tutorial 3 by combining the IO Pi Plus interrupts with the GPIO interrupts on the Raspberry Pi....
IO Pi Plus Tutorial - MQTT Reading the Ports
In this tutorial, we will use MQTT (Message Queue Telemetry Transport) to communicate with an IO Pi Plus to read the status of the pins, which are all set as inputs. You will need your Raspberry Pi and an IO Pi Plus for this. You will also need a second computer as the server/host device....
IO Pi Plus with Raspberry Pi Pico
The IO Pi Plus can be used with the Raspberry Pi Pico available at www.raspberrypi.com/products/raspberry-pi-pico/...
IO Pi Plus Tutorial - MQTT Control
This tutorial will use MQTT (Message Queue Telemetry Transport) to communicate with an IO Pi Plus using the pins as outputs to switch on and off remotely. For this, you will need your Raspberry Pi and an IO Pi. You will also need a second computer as the server/host device....
Driving Relays or higher loads with the IO Pi Plus
The IO Pi Plus expansion board can drive up to 25mA per channel, but to drive higher loads, such as relays or some optoisolators, you will need to boost the output using a transistor or MOSFETs....
16 Channel Opto-Isolated Input Board
In 2017 we released the design files for a relay board to work with our IO Pi Plus interface board. We made the design and Gerber files public, so anyone can make their own or modify the design to fit their needs. We are releasing the design files for an opto-isolated input board to accompany the relay board....
Relay Board for the IO Pi Plus 2.1
We often receive requests for a relay board to work with our IO Pi Plus expansion board. Developing and selling a relay board is something we have looked at several times in the past, but the problem we have found is making something that fits everyone’s needs. Relays come in a wide range of voltages, and while one person may need a board that works at 5V, another will need it to work at 24V. We would need to build and sell several different models to make boards suitable for everyone. ...