Arduino MicroPython Ultrasonic Sensor
This tutorial teaches you how to measure the distance to an object using an ultrasonic sensor with an Arduino and MicroPython. Specifically, we will cover:
- How to connect an ultrasonic sensor to an Arduino
- How to write MicroPython code for the Arduino to measure distance using the ultrasonic sensor
Hardware Preparation
Or you can buy the following sensor 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.
Additionally, some of these links are for products from our own brand, DIYables.
Overview of Ultrasonic Sensor
The HC-SR04 ultrasonic sensor measures the distance to objects using ultrasonic waves. It sends out a ultrasonic wave that humans can't hear and listens for the echo that returns after hitting an object. By measuring the time it takes for the ultrasonic wave to come back, the sensor determines the distance from it to the object.
Pinout
The HC-SR04 ultrasonic sensor includes four pins.
- VCC pin: Attach this pin to VCC (5 volts).
- GND pin: Attach this pin to GND (0 volts).
- TRIG pin: Link this to the Arduino to send control signals.
- ECHO pin: This sends signals back to the Arduino, which detects these signals to determine distance.
image source: diyables.io
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
※ NOTE THAT:
- You can use any digial I/O pin of Arduino Giga to connect directly to the TRIG pin of ultrasonic sesor.
- You can use any digial I/O pin of Arduino Giga to connect directly to the ECHO pin of ultrasonic sesor, except for the following pins: D5, D76, D77, D79, D84, D85, A0, A1, and A3. This is because these specific pins are only 3.3V tolerant. In case you need to use these pins, please use a voltage divider to reduce the 5V output from the sensor to 3.3V or lower, ensuring the voltage stays within the safe operating range for those pins.
Arduino MicroPython Code
"""
This Arduino MicroPython script was developed by newbiely.com
This Arduino MicroPython script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-micropython/arduino-micropython-ultrasonic-sensor
"""
from DIYables_MicroPython_Ultrasonic_Sensor import UltrasonicSensor
import time
TRIG_PIN = 'D3' # The Arduino Giga WiFi pin D3 connected to TRIG pin of the ultrasonic sensor
ECHO_PIN = 'D2' # The Arduino Giga WiFi pin D2 connected to ECHO pin of the ultrasonic sensor
sensor = UltrasonicSensor(trig_pin=TRIG_PIN, echo_pin=ECHO_PIN)
sensor.set_detection_threshold(140) # Set detection threshold to 140 cm
sensor.enable_filter(num_samples=20) # Enable filtering and set number of samples to 20
while True:
sensor.loop() # Perform measurement cycle
distance = sensor.get_distance()
if not distance:
print('No object detected within the set distance')
else:
# Print the distance formatted to two decimal places using format()
print('Distance: {:.2f} cm'.format(distance))
time.sleep(0.1)
Detailed Instructions
Here’s instructions on how to run the above MicroPython code on Arduino with Thonny IDE:
- Make sure Thonny IDE is installed on your computer.
- Make sure MicroPython firmware is installed on your Arduino board.
- If you are new to Arduino with MicroPython, see the Getting Started with Arduino and MicroPython.
- Connect the Arduino board to the ultrasonic sensor as shown in the above diagram.
- Connect the Arduino board to your computer with a USB cable.
- Open Thonny IDE and go to Tools Options.
- Under the Interpreter tab, select MicroPython (generic) from the dropdown menu.
- Select the COM port corresponding to your Arduino board (e.g., COM33 on Windows or /dev/ttyACM0 on Linux).
- In Thonny IDE, Navigate to the Tools Manage packages on the Thonny IDE.
- Search “DIYables-MicroPython-Ultrasonic-Sensor”, then find the Ultrasonic Sensor library created by DIYables.
- Click on DIYables-MicroPython-Ultrasonic-Sensor, then click Install button to install Ultrasonic Sensor library.
- Copy the provided Arduino MicroPython code and paste it into Thonny's editor.
- Save the MicroPython code to your Arduino by:
- Clicking the Save button or pressing Ctrl+S.
- In the save dialog, choose MicroPython device and name the file main.py.
- Click the green Run button (or press F5) to execute the code.
- Wave your hand in front of the ultrasonic sensor.
- Check the Shell at the bottom of Thonny IDE for the Arduino output.
Shell x
>>> %Run -c $EDITOR_CONTENT
MPY: soft reboot
No object detected within the set distance
No object detected within the set distance
No object detected within the set distance
No object detected within the set distance
Distance: 9.90 cm
Distance: 10.34 cm
Distance: 10.70 cm
Distance: 11.83 cm
Distance: 13.66 cm
Distance: 14.18 cm
Distance: 16.00 cm
Distance: 17.64 cm
Distance: 19.64 cm
Distance: 21.21 cm
Distance: 21.41 cm
No object detected within the set distance
No object detected within the set distance
No object detected within the set distance
MicroPython (generic) • Giga Virtual Comm Port in FS Mode @ COM33 ≡
Code Explanation
You can find the explanation in the comments of the Arduino MicroPython code mentioned above.
Video Tutorial
Ultrasonic Sensor Applications
- Avoiding Accidents
- Ensuring Capacity
- Measuring Elevation
- Detecting Proximity