How To | Adding a NO/NC relay to any Core with GPIO outputs
Learn how to easily incorporate a NO/NC relay to enhance the functionality of any device with GPIO outputs.
Procedure
Sometimes it may be necessary to use a relay to attach 3rd party hardware GPIO inputs that require either unknown voltage, or voltage that is out of range to the Core.
While there are many options out there to do this, below are two useful recommendations to accomplish this.
Option 1
The unit shown below is 4 channel NO/NC relay that operates off 12vdc coil voltage and 12dvc inputs triggers. It is opto-isolated so flyback voltage cannot damage the Core GPIO. It pulls about .25 mA to energize the coil. There is also a High/Low edge jumper. When set to Low Edge, it operates as energized when the button is pressed on the GPIO output component when the output is set to Open Collector.
Option 2
The unit shown below is 4 channel NO/NC relay that operated off 12vdc coil voltage and up to 5dvc inputs triggers. It is opto-isolated so flyback voltage cannot damage the Core GPIO . It pulls about .25 mA to energize the coil. There is also a High/Low edge jumper. When set to High Edge, it operates as energized when the button is pressed on the GPIO output component when the output is set to Digital Outputs.
Connection Diagram
