Example 28: Reed Switch Sensor

Experiment Overview

A reed switch (magnetic control switch) closes its contacts when near a magnet, suitable for door/window open-close detection, water meter pulse counting, and similar applications. Contacts open when no magnetic field is present and close when a magnetic field is detected.

Hardware Wiring

Board Label	GPIO Pin	Connected Device
REED	GPIO4	Reed switch module (DO digital output)

JSON Configuration Example

{
  "peripherals": [
    {
      "id": "reed_01",
      "name": "Reed Switch Sensor",
      "type": 13,
      "enabled": false,
      "pins": [4],
      "params": {}
    }
  ]
}

Peripheral Execution Linkage

Scenario: Door/Window Open Alarm (Polling Trigger)

Feature: Check door/window status every 200ms; trigger buzzer alarm when door/window is opened

Web UI Configuration Steps

Step 1: Ensure Buzzer Peripheral is Configured

• Peripheral ID: buzzer_gpio
• Type: GPIO Output

Step 2: Create Rule

1. Click Peripheral Execution in the left menu
2. Click New Rule button
3. Fill in basic configuration:
   • Rule Name: Door/Window Open Alarm
   • Report Data: ✅ Enabled
   • Enable: ✅ Enabled

Step 3: Configure Trigger (Polling Trigger)

1. Click Add Trigger button

2. Fill in trigger configuration:

   Field	Value	Description
   Trigger Type	Select Polling Trigger	Periodic condition check
   Target Peripheral	Select reed_01	Reed switch sensor
   Polling Interval	200	200ms
   Condition Expression	value == 1	HIGH = door/window open

Step 4: Configure Actions (2 actions required)

Action 1: Buzzer Alarm

1. Click Add Action button
2. Fill in:
   • Action Type: Select HIGH
   • Target Peripheral: Select buzzer_gpio

Action 2: Send Alarm Event

1. Click Add Action button again

2. Fill in:

   • Action Type: Select Send Event
   • Event Type: alarm
   • Event Message: Door/window has been opened

3. Click Save button

Installation Guide

Component	Installation Location	Description
Magnet	On door/window sash	Moves with door/window
Reed Switch	On door/window frame	Fixed in place
Trigger Distance	10-20mm	Typical distance

Notes

1. Installation Position: Place the magnet on the door/window sash; fix the reed switch on the door/window frame
2. Trigger Distance: Typical trigger distance is 10-20mm
3. Counting Applications: Water/gas meter pulse counting can use interrupt mode (type: 18)
4. Sealing: Waterproof enclosure is required for outdoor use