If you are interested on learning about LiDAR and how to use it with Arduino, you have come to the right place! In this post I will be going over how to use LiDAR with Arduino and will use the Benewake TF-Luna as the basis for the application.
What is LiDAR?
LiDAR stands for Light Detection and Ranging and is used to measure distance. It uses the TOF (Time-of-Flight) concept which basically use the time it takes for a light signal to travel to determine the distance to an object (based on already knowing the speed of light). The light signal will be emitted from the sensor and will return (traveling twice the distance between the sensor and the object of interest). We know the speed of light (3*108 m/s), so we can use these two to calculate the distance to the object.
Example LiDAR Sensor – TF-Luna from Benewake
The TF-Luna sensor is a LiDAR sensor based on the Time-of-Flight principle previously discussed. It is able to measure distances from 0.2 meters (7.8 inches) up to 8 meters (~26 feet) and has a resolution of 1cm (0.4 inches). The sensor accuracy is 6cm when measuring less than 3 meters (9.8 feet) and 2% when measuring between 3-8 meters (9.8 feet to 26 feet). Meaning that when measuring 8 meters, the accuracy would be 16 cm (6.3 inches). The power supply voltage is 3.7V – 5.2V.
TF-Luna Pin Connections
- Pin #1 – +5V – Power Supply
- Pin #2 – RXD/SDA – Receiving/Data
- Pin #3 – TXD/SCL – Transmitting/Clock
- Pin #4 – GND – Ground
- Pin #5 – Configuration Input
- Ground: I2C Mode
- Disconnected / 3.3V: Serial Mode
- Pin #6 – Multiplexing Output
- On/off mode: Output
- I2C Mode: Data ready signal
Connecting LiDAR (TF-Luna) to Arduino UNO or NodeMCU
The images below show how to connect the LiDAR sensor TF-Luna to an Arduino UNO or a NodeMCU. Both scenarios are based on running in I2C mode (connecting pin #5 of the TF-Luna to ground).
Below is a simple example Arduino code of taking measurements with the TF-Luna and displaying them on the Arduino IDE serial monitor.
#include <Wire.h> // Instantiate the Wire library
#include <TFLI2C.h> // TFLuna-I2C Library v.0.1.1
int16_t tfDist; // distance in centimeters
int16_t tfAddr = TFL_DEF_ADR; // Use this default I2C address
Serial.begin(115200); // Initalize serial port
Wire.begin(); // Initalize Wire library
Serial.println(String(tfDist)+" cm / " + String(tfDist/2.54)+" inches");
The images below show readings from the LiDAR TF-Luna at varying distances from the object being measured. A tape measured is placed on the floor to show the distance between the object and the sensor, and you can also see the distance measured by the sensor as it is displayed within the Arduino IDE Serial Monitor.
Components used in this example
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|LiDAR Sensor – Benewake TF-Luna||https://ebay.us/TB7e6a|