SENSORS/ACTUATORS

Arduino MKR WiFi 1010 - Motion Sensor

#UPDATE_NOTE: REWRITTEN, CHECKED_CODE

Detect movement and build smart automation with your Arduino MKR WiFi 1010 and HC-SR501 motion sensor! This tutorial teaches you how to use PIR motion sensors with Arduino MKR WiFi 1010 for security systems, automatic lighting, and presence detection. Learn how to wire the HC-SR501 sensor to your Arduino MKR WiFi 1010, read motion signals, detect when movement starts and stops, and trigger actions based on motion detection. Perfect for building Arduino MKR WiFi 1010 projects like automatic lights, security alarms, and energy-saving systems.

What You'll Learn

Connecting HC-SR501 motion sensors to your Arduino MKR WiFi 1010
Reading motion detection signals with Arduino MKR WiFi 1010
Programming Arduino MKR WiFi 1010 to detect movement start and stop
Using digital input pins on Arduino MKR WiFi 1010 for motion sensors
Adjusting HC-SR501 sensitivity for Arduino MKR WiFi 1010 projects
Building security systems with Arduino MKR WiFi 1010 and motion detection
Creating automatic lighting with Arduino MKR WiFi 1010 motion sensors

Real-World Applications

Security alarms: Trigger Arduino MKR WiFi 1010 alarms when motion is detected
Automatic lighting: Turn lights on with Arduino MKR WiFi 1010 when someone enters
Energy saving: Arduino MKR WiFi 1010 systems that power off when no motion
Intruder detection: Monitor spaces with Arduino MKR WiFi 1010 motion alerts
Smart doors: Automatic door opening using Arduino MKR WiFi 1010 sensors
Presence counting: Track room occupancy with Arduino MKR WiFi 1010
Pet monitoring: Detect pet activity with Arduino MKR WiFi 1010 motion sensing

Motion sensors are essential for Arduino MKR WiFi 1010 automation and security projects!

Arduino MKR WiFi 1010 HC-SR501 PIR Motion Senso

Hardware Preparation

1	×	Arduino MKR WiFi 1010
1	×	Micro USB Cable
1	×	HC-SR501 Motion Sensor
1	×	Alternatively, AM312 Mini Motion Sensor
1	×	Breadboard
1	×	Jumper Wires
1	×	Optionally, DC Power Jack

Or you can buy the following kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .

Overview of HC-SR501 Motion Sensor

The HC-SR501 is a PIR (Passive Infrared) motion sensor that detects movement by sensing changes in infrared radiation. It's commonly used in automatic lighting, security systems, and presence detection applications.

HC-SR501 Motion Sensor Pinout

The HC-SR501 has three pins:

VCC pin: Connect to 5V power supply
GND pin: Connect to ground (0V)
OUTPUT pin: Connect to any digital input pin on your Arduino MKR WiFi 1010

LOW when no motion detected
HIGH when motion detected

The sensor also features two adjustment potentiometers and a jumper for configuring sensitivity and timing. See the Advanced Uses section for detailed adjustment instructions.

How HC-SR501 Motion Sensor Works

The HC-SR501 detects motion by sensing changes in infrared (heat) radiation. For successful detection, two conditions must be met:

The object emits infrared radiation (body heat)
The object is moving or changing position

This means:

A person standing completely still won't be detected (no movement)
A cold robot moving won't be detected (no heat signature)
A moving person or animal will be detected (both heat and movement)

Important Note: The sensor detects movement, not specifically humans. When motion is detected, we infer human presence. This can lead to false negatives when people are present but stationary. However, the sensor's affordability and reliability make it excellent for most applications where occasional false negatives are acceptable.

Arduino MKR WiFi 1010 and HC-SR501 Motion Sensor

Reading the motion sensor with your Arduino MKR WiFi 1010 is simple! Configure a digital input pin, connect it to the sensor's OUTPUT pin, and use digitalRead() to check for HIGH (motion detected) or LOW (no motion) states.

Wiring Diagram - Two Power Options

The wiring diagram between Arduino MKR WiFi 1010 Motion Sensor

This image is created using Fritzing. Click to enlarge image

Wiring Table

HC-SR501 Motion Sensor	Arduino MKR WiFi 1010
VCC	5V
GND	GND
OUTPUT	D18

Initial Setting


Detection Range Adjuster	Fully screw it in the clockwise direction.
Time Delay Adjuster	Fully screw it in the anti-clockwise direction.
Repeat Trigger Selector	Put jumper like the below image.

How To Program Motion Sensor

Set one of the pins on your Arduino MKR WiFi 1010 board as a digital input using the pinMode() function.

pinMode(PIN_TO_SENSOR, INPUT);

Check the sensor's OUTPUT pin using the digitalRead() function.

motion_state = digitalRead(PIN_TO_SENSOR);

Detect when movement starts (when the pin changes from off to on)

prev_motion_state = motion_state; // save the previous sensor state motion_state = digitalRead(PIN_TO_SENSOR); // update the current sensor state if (prev_motion_state == LOW && motion_state == HIGH) { // check for a transition from LOW to HIGH Serial.println("Motion detected!"); }

Detect when movement stops (when the pin changes from HIGH to LOW)

prev_motion_state = motion_state; // preserve the previous state motion_state = digitalRead(PIN_TO_SENSOR); // obtain the current sensor reading if (prev_motion_state == HIGH && motion_state == LOW) { // detect a change from HIGH to LOW Serial.println("Motion stopped!"); }

Arduino MKR WiFi 1010 Code

/* * This Arduino MKR WiFi 1010 code was developed by newbiely.com * * This Arduino MKR WiFi 1010 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-mkr/arduino-mkr-wifi-1010-motion-sensor */ #define PIN_TO_SENSOR D18 // Arduino MKR WiFi 1010 pin linked to the sensor's output int motion_state = LOW; // holds the current sensor reading int prev_motion_state = LOW; // retains the previous sensor reading void setup() { Serial.begin(9600); // Start serial communication for the Serial Monitor pinMode(PIN_TO_SENSOR, INPUT); // Set the Nano 33 IoT pin as an input to read the sensor output } void loop() { prev_motion_state = motion_state; // Save the previous state value motion_state = digitalRead(PIN_TO_SENSOR); // Get the current state from the sensor if (prev_motion_state == LOW && motion_state == HIGH) { // Transition detected: LOW to HIGH Serial.println("Motion detected!"); // TODO: activate alarm, lighting, or another device as needed } else if (prev_motion_state == HIGH && motion_state == LOW) { // Transition detected: HIGH to LOW Serial.println("Motion stopped!"); // TODO: deactivate alarm, light, or another device as needed } }

Detailed Instructions

New to Arduino MKR WiFi 1010? Complete our Getting Started with Arduino MKR WiFi 1010 tutorial first to set up your development environment.

Wire the components according to the diagram above
Connect the Arduino MKR WiFi 1010 to your computer via USB cable
Open Arduino IDE and select the correct board and COM port
Copy the code and upload it to your board
Open the Serial Monitor

How to open serial monitor on Arduino IDE

Wave your hand in front of the motion sensor
View motion detection results on the Serial Monitor:

COM6

Send

Motion detected! Motion stopped!

Autoscroll Show timestamp

Clear output

9600 baud

Newline

Challenge Yourself

Ready to take your motion sensing skills further? Try these exciting projects:

Automatic Room Lights: Make LEDs or relays turn lights on when motion is detected and off after no motion for 30 seconds
Security Alarm System: Trigger a buzzer and send WiFi alerts when motion is detected in restricted areas
People Counter: Count how many times people enter/exit a room using motion detection timing
Smart Fan Controller: Automatically turn on a fan when someone enters and turn it off when they leave
Multi-Zone Detection: Use multiple motion sensors to track movement through different rooms
Pet Activity Monitor: Log your pet's activity patterns throughout the day using motion detection
Energy-Saving System: Build a comprehensive system that controls lights, fans, and displays based on presence detection

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