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The AB Electronics UK Knowledge Base provides support solutions, tutorials and troubleshooting guides.

Knowledge Base

IO Pi

Driving Relays or higher loads with the IO Pi

The output from the IO expansion boards can drive up to 25mA per channel but to drive higher loads such as relays or some opto-isolators you will need to boost the output using a transistor or mosfets. The circuit below shows how you can operate a 5V coil relay using either a GPIO output from...

IO Pi Tutorial 1 - The Blinking LED

In this tutorial we will start with a blinking LED and then build a binary counter using 8 LEDs.  For this you will need your Raspberry Pi, an IO Pi, 8 red LEDs and 8 200R resistors. We will use the AB Electronics python library to talk to the IO Pi, to download the library visit our Python...

IO Pi Tutorial 2 - Push the Button

In this tutorial we will add a button and an LED to the IO Pi and detect when the button has been pressed.  For this you will need your Raspberry Pi, an IO Pi, 1 red LED, 1 200R resistor and a push button. If you have already completed tutorial 1 then you can jump straight to stage 1,...

IO Pi 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. In this tutorial we are going to expand on Tutorial 2 by introducing interrupts. What are interrupts? In the IO Pi Plus an interrupt is a piece...

IO Pi 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 are going to expand on Tutorial 3 by combining the IO Pi Plus interrupts with the GPIO interrupts on the Raspberry Pi. By connecting the IO Pi...

Relay Board for the IO Pi Plus 2.1

We often get 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...

IO Pi Tutorial - MQTT Control

In this tutorial we will use MQTT (Message Queue Telemetry Transport) to communicate with an IO Pi 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 to act as the server/host device. We will use...

IO Pi Tutorial - MQTT Reading the Ports

In this tutorial we will use MQTT (Message Queue Telemetry Transport) to communicate with an IO Pi to read the status of the pins which are all set as inputs. For this you will need your Raspberry Pi and an IO Pi. You will also need a second computer to act as the server/host device. We will use...