Discover Radar Magic with DNG-TOF20 Leave a comment

The World of Miniature Radars

In the world of drones, autonomous robots, security systems, and industrial automation, precise distance measurement is one of the most vital requirements. Among various distance measurement technologies, LiDAR (Light Detection and Ranging) technology has created a remarkable transformation as an accurate, fast, and reliable solution.

Unlike ultrasonic sensors that have limited accuracy or infrared sensors that are affected by ambient light, LiDAR is capable of measuring distance with millimeter precision using laser pulses. The DNG-TOF20 module is an advanced and cost-effective example of LiDAR technology, belonging to the category of ToF (Time-of-Flight) sensors. This module, by sending infrared laser pulses and measuring their return time, can calculate the distance to objects in the range of 0.1 to 20 meters with an accuracy of ±1 cm at a sampling rate of 200 Hz. The module supports serial (UART) and I2C communication, giving you full flexibility in your designs.

Key features of the DNG-TOF20 include low power consumption (only 0.33 watts in operating mode), resistance to ambient light (up to 100 kilolux), ability to operate in various weather conditions, and its compact size that enables mounting on moving platforms such as robots and drones.

In this article, we will examine the DNG-TOF20 module. We start with the operating principles of ToF technology and the technical specifications of the module, then teach the practical setup, communication protocol, and how to program it for microcontrollers. We will also explore the diverse applications of this module in real projects, from 3D mapping and obstacle avoidance in robotics to surveillance and industrial systems. Join us to discover the amazing world of laser-based distance measurement.

How Do LiDAR and ToF Technology Work?

LiDAR (Light Detection and Ranging) is a remote sensing technology that calculates the distance to objects by sending laser light pulses and measuring the time it takes for them to return. The foundation of LiDAR is based on ToF or Time-of-Flight – the same concept we see in athletics competitions: an object travels a path and the round-trip time is measured.

In ToF technology, a laser pulse is sent toward the target at the speed of light (≈ 300,000 km/s). After hitting the object, the pulse is reflected and returns to the sensor. By precisely measuring the round-trip time (t) and using the simple formula distance = (speed of light × time) / 2, the distance to the object is calculated. The accuracy of this method is so high that it can even detect millimeter-level changes. Later we will have a comparison of different technologies.

As you can see in this table, various technologies exist with different applications, each suitable for specific purposes. The module we are examining here creates a good balance between low-cost but low-accuracy technologies (such as ultrasonic) and very expensive industrial systems by combining high accuracy, suitable range, and affordable price. This module is considered an ideal option for projects that need higher accuracy than ultrasonic sensors but have a limited budget for purchasing industrial LiDAR systems.

Module Introduction: Technical Specifications

In the table below you can see a summary of this module’s specifications.

As you can see in the module specifications table, this module offers outstanding features including:

• High accuracy
• Impressive measurement range
• Suitable sampling rate
• Low sensitivity to strong ambient light
• Very efficient power consumption
• Compact size and lightweight design

These characteristics make it an ideal choice for projects that demand both precision and speed.

Communicating with the Module

Communication via UART

As previously mentioned, this module supports both I2C and UART protocols. You can select which communication interface to use by setting a specific pin — the one labeled INT in the image — to either logic 0 (low) or logic 1 (high).

By pulling this INT pin to 0 or 1 (usually done by connecting it to GND or VCC, or via a pull-up/pull-down configuration), you tell the module whether it should operate in UART mode or I2C mode.

This simple hardware selection gives you flexibility to integrate the DNG-TOF20 with a wide variety of microcontrollers and development boards using the interface that best suits your project.

 

To communicate with the module in UART mode, apply the following configuration:

• Baud Rate: 115200
• Parity: None
• Data Bits: 8
• Stop Bits: 1
• Flow Control: None

The supported baud rate range is from 9600 (minimum) to 921600 (maximum). Important: All communication with the module must follow the protocol described below — no other formats are accepted.

Recommended Power-Up Sequence:

1. First connect the module’s main power line to 3.3V (usually labeled 3V3 or VCC).
2. Send any necessary configuration commands.
3. Only then connect/apply power to the laser line (3V3_LASER) to turn on the laser emission.

UART Command Frame Format

All commands sent via UART must follow this exact structure: UART Command Frame Format

As examples, you can use the following messages to access various module features:

Communication with the Module via I2C

To use I2C, first connect the GPIO pin (mentioned earlier in the UART section) with a pull-up resistor so the module enters I2C communication mode. Then configure I2C as follows:

In this communication, the microcontroller acts as Master and the module acts as Slave. First send the configuration message, then wait 100 milliseconds for the command to be processed. No waiting is required to read the measurement result. The I2C registers are as shown in the table below:

Module Output

The TFmini Plus module can send data via the serial port in two different formats, and you can switch between these formats using a command.

• Standard data output format (default)
• Character string format

Character String Format In this mode, output data is sent as text with unit in meters (m). For example, if the measured distance is 1.21 meters, the output will be:

 

(i.e., after the number, CR and LF line-ending characters are sent.)

Standard Data Output Format (default) In this mode, each data frame consists of 9 bytes and contains the following information:

1. Distance value
2. Signal strength
3. Chip temperature
4. Data validity check byte (Checksum)

All data is sent in hexadecimal (HEX) and each frame is exactly 9 bytes as follows:

Example of received packets:

Testing the Module on Windows

For this, you need the (WINCC_TF) program which you can download from this link. After that, set up the module in the order previously described and communicate with the module using a USB-Serial converter and the downloaded program, similar to what is shown in the image.

Communicating with the Module Using a Microcontroller

Programming for this module is not difficult because you have all the necessary information, but to speed up the product development process, here we will examine the code we have prepared for you.

In this code, first the correct establishment of communication is checked, then a request to receive information is sent to the module via UART, and the data is checked and displayed.

The Arduino sketch is as follows:

First, by requesting the firmware version, we check that the hardware connections are correctly established, and then we use the read Data function. This function extracts the distance, strength, and temperature from the packet sent by the module and displays them. It also checks the Checksum and Strength, and if they have incorrect values, it notifies the user.

This function is as follows:

If the program works correctly, you will have an output like the following:

 

To download and use this code, you can visit the following Git address.
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