The digital inputs of the Andino IO can be further expanded by connecting Andino X1 boards (without a Raspberry Pi inside) to the USB ports of the Raspberry Pi. The Pi can then connect to the X1 boards via serial. Using this method offers the following benefits:

Raspberry Pi expansion board with Andino X1 connected via USB

To connect the Andino X1 boards to the Andino IO, The X1s have to be connected to the Andino IO using USB (Type A) to Mini-USB cables. The X1 boards also need a separate power source. The easiest way to provide this, is to connect the power inputs on the X1 housings to the power supply of the Andino IO in parallel. The X1 boards also need to be set to the USB configuration. This can be done by moving the jumpers on the board, located directly next to the A-E pins, to a different position:

The X1 inputs can now be accessed via the Andino IO. This can be done via any application that supports sending and receiving serial messages (e.g. Node-Red). For testing purposes, however, minicom provides a good solution.

If you have not yet installed minicom, log into the RaspberryPi via SSH and do so by running:

sudo apt install minicom

After the installation is complete, first check if the Andino X1 boards are detected properly. Running

ls /dev/ttyUSB*

should display the same number of devices that you have connected.

Afterwards, the minicom setup can be entered. To do so, run:

sudo minicom --setup

Here, navigate to Serial port setup and enter the following settings:

Minicom serial port setup X1 IO connection

Change /dev/ttyUSB0 to your desired USB device. After the settings have been entered, hit Enter to close the menu again and then choose Exit from the main setup menu.

You will now receive the status messages of one of the X1 boards. How these messages can be interpreted can be found in our tutorial on the Andino firmware. To close minicom again, press Ctrl + A, followed by X. Then confirm that you want to leave minicom.