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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.
| Technology | Principle of Operation | Measurement Range | Accuracy | Speed | Environmental Sensitivity | Cost | Common Applications |
|---|---|---|---|---|---|---|---|
| LiDAR (ToF) – lightweight model | Laser pulse + Time of Flight | Few cm to several meters | Very high (±1 cm) | Very high (up to 200 Hz) | Direct light, fog | Medium | Robotics, drones, mapping |
| Industrial / Military LiDAR | Laser pulse + Time of Flight | Up to 10+ km | Millimeter level | High | Adverse weather | Very high | Topography, defense systems |
| Ultrasonic | Sound waves + Echo | Few cm (typical) | Medium | Low (10–20 Hz) | Temperature, wind | Very low | Parking sensors, level measurement |
| Infrared (IR) – triangulation | Angle triangulation | 10 cm – 5 m | Low | Medium | Ambient light, color | Low | Line following robots |
| mmWave Radar (RF) | Millimeter radio waves | 0.1 – 250 m | High | High | Low | Medium–High | Autonomous vehicles, industry |
| Military / Airborne Radar | Radio waves + Doppler | Up to 400+ km | Variable | Very high | Almost unaffected | Very high | Air defense, meteorology |
| Computer Vision (Stereo) | Stereo image processing | Depends on field of view | Variable | Low | Light, texture | High | Face recognition, AR |
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.
| Item | Min | Typical | Max | Unit | Description |
|---|---|---|---|---|---|
| Measurement Frequency | 50 | 100 | 250 | Hz | Number of distance measurements per second (50/100/250 Hz) |
| Measurement Range | 0.1 | – | 20 | m | With 80% reflectivity |
| Relative Error | – | – | – | – | – |
| – | 30 | – | mm | 0.2 m ≤ distance < 1 m | |
| – | 60 | – | mm | 1 m ≤ distance ≤ 6 m | |
| – | – | 1% | – | % | distance > 6 m (percentage of measured distance) |
| Ambient Light Condition | – | 100,000 | – | lux | – |
| Operating Voltage | – | 3.3 | – | V | – |
| Operating Current | 20 | 105 | 150 | mA | – |
| Power Consumption | 66 | 346 | 495 | mW | Based on 150 mA at 3.3 V |
| Operating Temperature | –20 | 25 | +50 | °C | – |
| Storage Temperature | –20 | 25 | +80 | °C | – |
| Dimensions (L × W × H) | – | 21 × 15 × 7.87 | – | mm | – |
| Weight (Net) | – | 1.35 | – | g | Net weight |
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:
- First connect the module’s main power line to 3.3V (usually labeled 3V3 or VCC).
- Send any necessary configuration commands.
- 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
| Byte | Name | Description |
|---|---|---|
| Byte 0 | Head | Command frame header (fixed value: 0x5A) |
| Byte 1 | Len | Total length of the command frame (including Head and Checksum, in bytes) |
| Byte 2 | ID | Command identifier (determines how to parse different commands) |
| Byte 3 to Byte N-2 | Payload | Data section; interpreted based on ID; data is in little-endian format |
| Byte N-1 | Checksum | Low 8 bits of the sum of all bytes from Head to Payload (sum & 0xFF) |
As examples, you can use the following messages to access various module features:
| Parameter | Command | Response | Description | Default |
|---|---|---|---|---|
| Get firmware version | 5A 04 01 5F | 5A 07 01 V1 V2 V3 SU | Firmware version (e.g. V3.2.1) | – |
| System reset | 5A 04 02 60 | 5A 05 02 00 61 (success) 5A 05 02 01 62 (fail) | – | – |
| Frame rate | 5A 06 03 LL HH SU | 5A 06 03 LL HH SU | 1–1000 Hz | 100 Hz |
| Trigger detection | 5A 04 04 62 | Data frame | After setting frame rate to 0, this command enables detection | – |
| Output format | 5A 05 05 01 65 5A 05 05 02 66 5A 05 05 06 6A | 5A 05 05 01 65 5A 05 05 02 66 5A 05 05 06 6A | Standard 9-byte (cm) ✓ Pixhawk compatible Standard 9-byte (mm) | Standard 9-byte (cm) |
| Baud rate | 5A 08 06 H1 H2 H3 H4 SU | 5A 08 06 H1 H2 H3 H4 SU | Set baud rate Example: 256000 (decimal) = 3E800 (hex), H1=00, H2=E8, H3=03, H4=00 | 115200 |
| Enable/disable output | 5A 05 07 00 66 5A 05 07 01 67 | 5A 05 07 00 66 5A 05 07 01 67 | Disable data output / Enable data output ✓ | Enabled |
| Set communication interface | 5A 05 0A MODE SU | 5A 05 0A 00 69 5A 05 0A 01 6A | 0 (UART) 1 (I2C) | UART |
| Change I2C address | 5A 05 0B ADDR SU | 5A 05 0B ADDR SU | Change I2C address | 0x10 |
| Get data frame | 5A 05 00 01 60 5A 05 00 06 65 | 9-byte data frame (cm) 9-byte data frame (mm) | Only works in I2C mode | – |
| Enable I/O mode | 5A 09 3B MODE DL DH ZoneL ZoneH SU | – | MODE: 0 – standard data mode 1 – I/O near high & far low 2 – I/O near low & far high Zone: hysteresis region | 0 (standard data mode) |
| Power threshold & below-threshold distance | 5A 07 22 XX LL HH 00 | 5A 07 22 XX LL HH SU | Example: When strength < 100, output distance 1200 cm XX=100/10=10(DEC)=0A(HEX) 1200(DEC)=4B0(HEX) LL=B0, HH=04 | Power threshold = 100 Below-threshold distance = 0 |
| Low power mode | 5A 06 35 0X 00 SU | 5A 06 35 0X 00 SU | X range (HEX) 0~A; frame rate in low-power mode cannot exceed 10 Hz X>0: low-power mode active X=0: low-power mode disabled | – |
| Factory reset | 5A 04 10 6E | 5A 05 10 00 6F (success) 5A 05 10 01 70 (fail) | – | – |
| Save settings | 5A 04 11 6F | 5A 05 11 00 70 (success) 5A 05 11 01 71 (fail) | – | – |
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:
| Parameter | Value | Description |
|---|---|---|
| Interface | I²C | Communication interface |
| Max transmission rate | 400 kbit/s | Data transfer speed |
| Master/Slave mode | Slave | Module operates as slave device |
| Default address | 0x10 | Default I²C address of the module |
| Address range | 0x01 to 0x7F | Configurable address range |
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:
| Address | R/W | Name | Initial Value | Description |
|---|---|---|---|---|
| 0x00 | R | DIST_LOW | — | Distance low byte (cm) |
| 0x01 | R | DIST_HIGH | — | Distance high byte |
| 0x02 | R | AMP_LOW | — | Amplitude low byte |
| 0x03 | R | AMP_HIGH | — | Amplitude high byte |
| 0x04 | R | TEMP_LOW | — | Temperature low byte (unit: 0.01 °C) |
| 0x05 | R | TEMP_HIGH | — | Temperature high byte |
| 0x06 | R | TICK_LOW | — | Timestamp low byte |
| 0x07 | R | TICK_HIGH | — | Timestamp high byte |
| 0x08 | — | Reserved | Hold | — |
| 0x09 | R | ERROR_LOW | Hold | — |
| 0x0A | R | VERSION_REVISION | — | Revised version |
| 0x0B | R | VERSION_MINOR | — | Minor version |
| 0x0C | R | VERSION_MAJOR | — | Major version |
| 0x0D–0x0F | — | Reserved | Hold | — |
| 0x10–0x1D | R | SN | — | Production code (14 bytes ASCII, 0x10 is first byte) |
| 0x1E–0x1F | — | Reserved | Hold | — |
| 0x20 | W | SAVE | — | Write 0x01 to save current settings |
| 0x21 | W | SHUTDOWN / REBOOT | — | Write 0x02 to reboot |
| 0x22 | W/R | SLAVE_ADDR | 0x10 | I²C address range: 0x08 – 0x77 |
| 0x23 | W/R | MODE | 0x00 | 0x00: Continuous mode 0x01: Trigger mode |
| 0x24 | W | TRIG_ONE_SHOT | — | 0x01: Trigger once (only in trigger mode) |
| 0x25 | W/R | ENABLE | 0x01 | 0x00: Turn off LiDAR 0x01: Turn on LiDAR |
| 0x26 | W/R | FPS_LOW | 0x64 | Frames per second low byte |
| 0x27 | W/R | FPS_HIGH | 0x00 | Frames per second high byte |
| 0x28 | W/R | HOLD | — | Reserved |
| 0x29 | W | RESTORE_FACTORY_DEFAULTS | — | Write 0x01 to restore factory defaults |
| 0x2A | W/R | AMP_THR_LOW | 0x2C | Amplitude threshold low byte |
| 0x2B | W/R | AMP_THR_HIGH | 0x01 | Amplitude threshold high byte |
| 0x2C | W/R | DUMMY_DIST_LOW | 0xFF | Dummy distance low byte |
| 0x2D | W/R | DUMMY_DIST_HIGH | 0xFF | Dummy distance high byte |
| 0x2E | W/R | MIN_DIST_LOW | 0x00 | Minimum distance low byte (mm) |
| 0x2F | W/R | MIN_DIST_HIGH | 0x00 | Minimum distance high byte |
| 0x30 | W/R | MAX_DIST_LOW | 0xFF | Maximum distance low byte (mm) |
| 0x31 | W/R | MAX_DIST_HIGH | 0xFF | Maximum distance high byte |
| 0x32–0x3B | — | Reserved | Hold | — |
| 0x3A–0x3F | R | SIGNATURE | — | ASCII string (e.g. “DNG-TOF20”) |
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:
| 1 | <span style="color: #000000;">1.21\r\n</span> |
(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:
- Distance value
- Signal strength
- Chip temperature
- Data validity check byte (Checksum)
All data is sent in hexadecimal (HEX) and each frame is exactly 9 bytes as follows:
| Byte | Name | Description |
|---|---|---|
| Byte 0 | 0x59 | Frame header (fixed) |
| Byte 1 | 0x59 | Frame header (fixed) |
| Byte 2 | Dist_L | Distance low 8 bits |
| Byte 3 | Dist_H | Distance high 8 bits |
| Byte 4 | Strength_L | Signal strength low 8 bits |
| Byte 5 | Strength_H | Signal strength high 8 bits |
| Byte 6 | Temp_L | Temperature low 8 bits |
| Byte 7 | Temp_H | Temperature high 8 bits |
| Byte 8 | Checksum | Low 8 bits of sum of bytes 0 to 7 |
🔗Important Notes
Distance represents the measured distance by the module, which is sent by default in centimeters as a decimal value.
Strength represents the returned signal strength and by default is in the range 0 to 65535.
If signal strength is less than 100 or equal to 65535 (saturation or overexposed condition occurs), the measurement is invalid and the module sets the distance value to 0.
Example of received packets:
| 1 2 3 4 5 | <span style="color: #000000;">59 59 DB 00 29 52 48 09 59 59 DB 00 26 52 48 09 59 59 DB 00 15 52 48 09 59 59 DB 00 FE 51 48 09 59 59 DB 00 EC 51 48 09</span> |
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:
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | <span style="color: #000000;">#include "TFS20.h" #define BAUDRATE 115200 // Use Serial1 for module (Pin 0 RX, Pin 1 TX) TFS20 lidar(Serial1); void setup() { Serial.begin(BAUDRATE); lidar.begin(BAUDRATE); Serial.println("TFS20 test start..."); if (!lidar.checkModule(500)) { Serial.println("ERROR: Module not responding"); while (1); } Serial.println("Module OK"); lidar.startContinuous(); Serial.println("Continuous mode started"); } void loop() { uint16_t distance, strength, tempRaw; if (lidar.readData(distance, strength, tempRaw)) { Serial.print("Distance: "); Serial.print(distance); Serial.print(" | Strength: "); Serial.print(strength); Serial.print(" | Temp raw: "); Serial.println(tempRaw); } }</span> |
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:
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | <span style="color: #000000;">bool TFS20::readData(uint16_t &distance, uint16_t &strength, uint16_t &tempRaw) { uint8_t buf[9]; if (serial.available() >= 9) { if (serial.read() == 0x59 && serial.read() == 0x59) { buf[0] = 0x59; buf[1] = 0x59; for (int i = 2; i < 9; i++) { buf[i] = serial.read(); } // Check checksum if (calcChecksum(buf, 8) != buf[8]) { return false; } distance = buf[2] | (buf[3] << 8); strength = buf[4] | (buf[5] << 8); tempRaw = buf[6] | (buf[7] << 8); // Strength validation if (strength >= 65535 || strength < 100) { return false; } return true; } } return false; }</span> |
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.
I hope you have made full use of this article and support us with your good comments:)
🔗Purchase DNG-TOF20 Module
If you are looking for a compact, high-speed, and accurate LiDAR module for your robotics, drone, industrial automation, or smart sensing projects, you can purchase the DNG-TOF20 module directly from EICUT Store and start developing your project with a reliable ToF distance measurement solution.
