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TFmini 12m UART LiDAR

What It Is

TFmini 12m UART is a small single-point LiDAR distance sensor. It measures one distance in front of the sensor, not a 2D scan.

Benewake TFmini-S product image

Image source: Benewake TFmini-S product page

TFmini time of flight principle

How it works:

  • The sensor sends near infrared light toward the target.
  • The light reflects back to the receiver.
  • The sensor estimates distance from the light time-of-flight / phase difference.
  • It outputs distance frames over UART.

The default output is a binary frame at 115200 baud, usually 100 Hz.

Main Specification

Parameter Typical value
Range 0.3-12 m indoor / weak ambient light
Blind zone 0-0.3 m, data is unreliable
Accuracy about +/-6 cm from 0.3-6 m, about +/-1% from 6-12 m
Resolution 1 cm
Default frame rate 100 Hz
Supply voltage 5 V
Average current up to about 140 mA
Peak current up to about 800 mA
Interface UART
UART default 115200, 8N1
UART logic level 3.3 V LVTTL

Warning

The sensor power is 5 V, but the UART logic is 3.3 V. Do not drive the TFmini RXD pin from a 5 V TTL UART without a logic level shifter.

Benewake TFmini Family

Benewake has several small single-point LiDAR modules with similar names. The table below is a practical comparison for choosing a module.

Model Range Interface Protection Power Suitable outside? Notes
TFmini, older UART 12 m module about 0.3-12 m UART no sealed enclosure 5 V Limited Good for indoor tests or protected mounting. Not a weatherproof outdoor sensor.
TF-Luna 0.2-8 m UART, I2C, I/O without enclosure <=0.35 W Limited Small and low power, but should be protected from water and dust.
TFmini-S 0.1-12 m UART, I2C, I/O IP65 <=0.7 W Yes Better option than old TFmini for outdoor or dusty use.
TFmini Plus 0.1-12 m UART, I2C, I/O IP65 about 550 mW Yes Robust 12 m option with sealed enclosure.
TFmini-i 0.1-12 m CAN, RS-485 IP65 <=0.8 W @ 12 V Yes Industrial version. Good for noisy wiring, but not a UART module.
TFS20-L 0.2-20 m UART, I2C without enclosure <=0.35 W Limited Longer range bare module. Use enclosure if mounted outside.

For outdoor use, prefer IP65 or better. A bare module can still measure outside in some conditions, but it is not protected from water, dust, or mechanical exposure.

Wiring

For the common original TFmini UART cable:

TFmini wire color TFmini pin Connect to host
Green TXD, 3.3 V UART output Host RX
White RXD, 3.3 V UART input Host TX through 3.3 V logic
Red +5V power 5 V supply
Black GND GND

TFmini UART wiring

Notes:

  • TX and RX are crossed: sensor TXD goes to host RX.
  • Connect grounds together.
  • A USB-to-TTL adapter should use 3.3 V logic for UART.
  • The sensor still needs 5 V power. Do not power it from 3.3 V.
  • If your adapter or microcontroller UART is 5 V, use a level shifter at least on host TXD -> TFmini RXD.
  • If you only read distance and do not send commands, connect only TXD, 5 V, and GND; leave TFmini RXD disconnected.

Python Read Example

Install dependency:

1
python3 -m pip install pyserial

Example:

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import serial


PORT = "/dev/ttyUSB0"
BAUD = 115200


def read_tfmini_frame(ser):
    while True:
        if ser.read(1) != b"\x59":
            continue
        if ser.read(1) != b"\x59":
            continue

        payload = ser.read(7)
        if len(payload) != 7:
            return None

        frame = b"\x59\x59" + payload
        checksum = sum(frame[:8]) & 0xFF
        if checksum != frame[8]:
            return None

        distance_cm = frame[2] + (frame[3] << 8)
        strength = frame[4] + (frame[5] << 8)
        temperature_raw = frame[6] + (frame[7] << 8)
        temperature_c = temperature_raw / 8.0 - 256.0

        return distance_cm, strength, temperature_c


def main():
    with serial.Serial(PORT, BAUD, timeout=0.1) as ser:
        while True:
            data = read_tfmini_frame(ser)
            if data is None:
                continue

            distance_cm, strength, temperature_c = data
            print(
                f"distance={distance_cm / 100:.2f} m "
                f"strength={strength} "
                f"temperature={temperature_c:.1f} C"
            )


if __name__ == "__main__":
    main()

For Raspberry Pi UART, the port may be /dev/serial0. For a USB-TTL adapter, it is commonly /dev/ttyUSB0 or /dev/ttyACM0.

Quick Check

If no data appears:

  • Check that the sensor has 5 V power and common ground.
  • Swap host RX and TX if the UART wiring may be reversed.
  • Confirm the serial port name.
  • Confirm baud rate is 115200.
  • Check that the host UART logic is 3.3 V.
  • Point the sensor at a target farther than 30 cm.

References