Example 38: IR Obstacle Sensor

Experiment Overview

An IR obstacle sensor emits infrared light and detects reflected signals to determine if there is an obstacle ahead. Outputs LOW when an obstacle is detected, suitable for automatic obstacle-avoiding robots, distance detection, and similar applications.

Hardware Wiring

Board Label	GPIO Pin	Connected Device
OUT	GPIO4	IR obstacle module DO output

The on-module potentiometer adjusts detection range (2~30cm).

JSON Configuration Example

{
  "peripherals": [
    {
      "id": "ir_obstacle_01",
      "name": "IR Obstacle",
      "type": 11,
      "enabled": false,
      "pins": [4],
      "params": {}
    }
  ]
}

Peripheral Execution Linkage

Scenario: Obstacle Stop (Polling Trigger)

Feature: Stop motors when obstacle is detected

Web UI Configuration Steps

Step 1: Ensure Motor Peripherals are Configured

• Motor IN1: motor_in1 (GPIO Output)
• Motor IN2: motor_in2 (GPIO Output)

Step 2: Create Rule

1. Click Peripheral Config in the left menu → Switch to Peripheral Execution tab
2. Click New Rule button
3. Fill in basic configuration:
   • Rule Name: Obstacle Stop
   • 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 ir_obstacle_01	IR obstacle sensor
   Polling Interval	50	50ms (fast response)
   Condition Expression	value == 0	Obstacle detected (LOW)

Step 4: Configure Actions (2 actions required)

Action 1: Stop Motor IN1

1. Click Add Action button
2. Fill in:
   • Action Type: Select LOW
   • Target Peripheral: Select motor_in1

Action 2: Stop Motor IN2

1. Click Add Action button again

2. Fill in:

   • Action Type: Select LOW
   • Target Peripheral: Select motor_in2

3. Click Save button

IR Obstacle Sensor Reference

Status	Output Level	Description
No Obstacle	HIGH (1)	Normal movement
Obstacle Detected	LOW (0)	Need to stop

Application Scenarios

Scenario	Description	Detection Range
Obstacle-Avoiding Robot	Forward obstacle detection	2-30cm
Limit Switch	Mechanical position limiting	2-30cm
Object Detection	Assembly line counting	2-30cm

Notes

1. Detection Range: Adjustable via potentiometer, typically 2-30cm
2. Color Impact: Black objects absorb infrared, potentially reducing detection range
3. Ambient Light: Strong IR light sources (sunlight) may cause interference
4. Mounting Angle: Sensor must face the detection direction