Single Relay unit
Relay Unit can be used as an electrically operated switch, uses an electromagnet to mechanically operate a switch, where it is necessary to control a large power load circuit by a separate low-power signal, like a digital signal output from a microprocessor. Up to 30V DC and 220V AC.
|  | • Port: B • Connection: Grove cable | 
|---|
Sensor configuration:
{
    {
  "m5devices": [
    {
      "uid": "M5",
      "sensors": [
        {
          "id": "relay",
          "type": "relay",
          "events": {
            "onOpen": {
              "event": "open"
            },
            "onClose": {
              "event": "close"
            }
          },
          "settings": {
            "pin": 21
          }
        }
      ]
    }
  ]
}
Simple usage in content
In this tutorial We will use M5 stack fire as device and a Single relay unit as sensor.
- 
This Unit uses the B(black)port in M5 stack fire so you have to attach the sensor with a Grove Cable into your device. Then connect your sensor into the screen where you wish to use it. 
- 
In Wallboard Sensor Designer, you have to make the sensor configuration. 
- 
When you open it you have to login into your editor account you use then make a fast connection to your sensor. 
- 
If you are connected, you have to choose port B, then relay. 
|  | 
|---|
- Enable the events you wish to use in your content, then send it to the screen you chose in the Content editor you use.
|  | 
|---|
If you wish to see or customize your sensor config:
- 
Open the Content editor where you sent the configuration, and focus to the screen you selected. 
- 
Right click on the screen: Manage screen >> Set>> Set sensor configuration 
How to make your content
|  | • Inside your content you will need 2 text widgets like this: • Name them as your events: - open - close | 
|---|
Then you need to add Touch actions to your text widgets:
Open:
|  | 
|---|
Close:
|  | 
|---|
Save then assign to your screen. When you click on the button you chose the relay receives the event.