{"id":353,"date":"2026-02-03T13:05:31","date_gmt":"2026-02-03T13:05:31","guid":{"rendered":"https:\/\/circuitdigest.com\/wiki\/?page_id=353"},"modified":"2026-03-11T07:11:37","modified_gmt":"2026-03-11T07:11:37","slug":"litewing-drone-positioning-module","status":"publish","type":"page","link":"https:\/\/circuitdigest.com\/wiki\/litewing-drone-positioning-module\/","title":{"rendered":"LiteWing Drone Positioning Module – Wiki Page"},"content":{"rendered":"\n

<\/span>Introduction<\/span><\/h2>\n\n\n\n

The LiteWing Drone Positioning Module is a plug-and-play optical flow and ToF-based stabilization add-on designed for indoor and GPS-denied flight. Featuring the PMW3901 optical flow sensor for precise X\/Y position tracking and the VL53L1X Time-of-Flight sensor for accurate height measurement, this module enables stable height hold and position hold performance. Ideal for DIY drones, autonomous flight experiments, and educational robotics projects.<\/p>\n\n\n\n

\n
\n

This module transforms your ESP32 LiteWing Drone <\/a>into a fully-equipped autonomous flight platform by adding critical sensor capabilities: precision ToF height measurement, optical motion tracking, and visual status feedback. All connected through a 24-pin connector, eliminating complex wiring while maintaining robust electrical connections suitable for flight operations.<\/p>\n\n\n\n

This add-on module is completely compatible with the LiteWing Drones and consists of the VL53L1x ToF sensor and PMW3901MB optical flow sensor for height hold and position hold, respectively. Apart from this, the module also has 4 Neopixel LEDs that can be programmed to indicate flight status or for visual appeal.<\/p>\n\n\n\n

Important<\/strong>: By default, only the ToF sensor, Optical Flow sensor, and Neopixel LEDs will be soldered on the module. The brometric sensor and magnetometer footprint is added only for users who wish to build more using the same board. By default these two sensors will not be populated. The colour of the PCB might also be in black or green color depending on the time of purchase, but features and working will reamin the same. <\/p>\n<\/div>\n\n\n\n

\n
\"Litewing
LiteWing Drone Positioning Module<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n
\n\n\n\n

<\/span>Specifications<\/strong><\/span><\/h2>\n\n\n\n
\n
\n
\"Drone<\/figure>\n<\/div>\n\n\n\n
\n
Specification<\/strong><\/td>Details<\/strong><\/td><\/tr>
Dimensions<\/strong><\/td>46mm \u00d7 44mm (L \u00d7 W)<\/td><\/tr>
Weight<\/strong><\/td>~8 grams (including components)<\/td><\/tr>
Connector<\/strong><\/td>24-pin male header pins (2\u00d712 configuration)<\/td><\/tr>
Power Requirements<\/strong><\/td>3.3V from drone (via connector)<\/td><\/tr>
Communication<\/strong><\/td>I\u00b2C (Height sensor), SPI (Optical flow), Single Wire (Neopixel)<\/td><\/tr>
Mounting<\/strong><\/td>Bottom-side of LiteWing drone via expansion headers<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n<\/div>\n\n\n\n
\n\n\n\n

<\/span>Quick Start Tutorials<\/strong> for Positioning Module with LiteWing Drone<\/span><\/h2>\n\n\n\n
\n
\n
<\/a>
\"drone<\/div>

1. Height Measurement using ToF Sensor<\/strong><\/p><\/div>

<\/div><\/div><\/div>\n<\/div>\n\n\n\n
\n
<\/a>
\"drone<\/div>

2. Position Tracking using Optical Flow Sensor <\/strong><\/p><\/div>

<\/div><\/div><\/div>\n<\/div>\n\n\n\n
\n
<\/a>
\"reading<\/div>

3. Reading Values from IMU Sensor (Optional)<\/strong><\/p><\/div>

<\/div><\/div><\/div>\n<\/div>\n<\/div>\n\n\n\n
\n
\n
<\/a>
\"neopixel<\/div>

4. How to Control Neopixel Status LEDs <\/strong><\/p><\/div>

<\/div><\/div><\/div>\n<\/div>\n\n\n\n
\n
<\/a>
\"position<\/div>

5. Position Hold on LiteWing Drone<\/strong><\/p><\/div>

<\/div><\/div><\/div>\n<\/div>\n\n\n\n
\n
<\/a>
\"drone<\/div>

6. Joystick Keyboard Control with Position Hold<\/strong><\/p><\/div>

<\/div><\/div><\/div>\n<\/div>\n<\/div>\n\n\n\n
\n
\n
<\/a>
\"automatic<\/div>

7. Autonomous Flight Path using LiteWing <\/strong><\/p><\/div>

<\/div><\/div><\/div>\n<\/div>\n\n\n\n
<\/div>\n\n\n\n
<\/div>\n<\/div>\n\n\n\n
\n\n\n\n

<\/span>Hardware Overview<\/strong><\/span><\/h2>\n\n\n\n

On the bottom side of the PCB, just above the Semicon Lab logo, we placed the VL53L1X <\/strong>Time-of-Flight distance sensor. This downward-facing ToF device provides precise ground height measurements, making it ideal for height hold and low-altitude autonomous flight.<\/p>\n\n\n\n

At the center of the module, you\u2019ll find the PMW3901 <\/strong>optical flow sensor. This positioning ensures an unobstructed view of the ground surface, allowing reliable X\/Y motion tracking for horizontal position hold and drift correction.<\/p>\n\n\n\n

\n
\n
\"litewing<\/figure>\n<\/div>\n\n\n\n
\n
\"litewing<\/figure>\n<\/div>\n<\/div>\n\n\n\n

Toward the bottom-left area of the board, we integrated a dedicated SPX3819M5-L-1-8<\/strong> LDO<\/strong> regulator, which supplies the required low-noise power rail for the optical flow sensor, ensuring stable operation and consistent motion data.<\/p>\n\n\n\n

For visual feedback and debugging, four WS2812B <\/strong>addressable RGB LEDs are placed at each corner of the module. This symmetric placement makes status indications clearly visible from any angle, while still using only a single data line for control. These LEDs are used for boot indication, mode status, calibration feedback, and general diagnostics.<\/p>\n\n\n\n

On the left side of the PCB, we\u2019ve also provided unpopulated footprints for two optional sensors: MS5611 barometric pressure sensor<\/strong> (for altitude estimation), HMC5883L magnetometer<\/strong> (for heading reference) At present, firmware support for these two devices is still under development. However, advanced users are welcome to populate these pads according to the provided schematics and modify the LiteWing source code to suit their requirements.<\/p>\n\n\n\n

All other onboard sensors, including the VL53L1X, PMW3901, and WS2812B LEDs, are natively supported on LiteWing after the firmware update, which we\u2019ll cover in the following sections.<\/p>\n\n\n\n

\n
\n
\n

VL53L1X Time-of-Flight Distance Sensor<\/strong><\/strong><\/p>\n\n\n\n

For height measurement, the shield uses the VL53L1X<\/strong>, a compact Time-of-Flight (ToF) module from STMicroelectronics. It operates using a 940 nm Class-1 laser emitter and a SPAD array to measure the return time of reflected photons. This approach provides consistent short-range height data and is less affected by airflow noise compared to ultrasonic sensors. The onboard microcontroller handles ranging calculations and outputs distance values directly over I\u00b2C, reducing processing load on the main flight controller.<\/p>\n\n\n\n

Specifications<\/strong><\/h4>\n\n\n\n
Parameter<\/strong><\/td>Value<\/strong><\/td><\/tr>
Ranging Distance<\/td>Up to 4 m<\/td><\/tr>
Measurement Rate<\/td>Up to 50 Hz<\/td><\/tr>
Emitter<\/td>940 nm IR (Class-1)<\/td><\/tr>
Receiver<\/td>SPAD array with integrated optics<\/td><\/tr>
Interface<\/td>I\u00b2C<\/td><\/tr>
Notes<\/td>Onboard firmware handles all ranging computations<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>
\"litewing<\/figure><\/div>\n<\/div>\n<\/div>\n\n\n\n
\n
\n
\"pmw3901<\/figure>
\n

PMW3901MB Optical Flow Sensor<\/strong><\/strong><\/p>\n\n\n\n

Horizontal drift correction is handled by the PMW3901MB-TXQT<\/strong>, an optical flow sensor designed for motion tracking in aerial platforms. The sensor continuously captures low-resolution surface images and computes X\/Y displacement between frames. It is suitable for indoor and GPS-denied environments where vision-based reference is required. And it allows stable operation during slow and low-altitude flight.<\/p>\n\n\n\n

Specifications<\/strong><\/h4>\n\n\n\n
Parameter<\/strong><\/td>Value<\/strong><\/td><\/tr>
Working Range<\/td>80 mm to 2m<\/td><\/tr>
Power Consumption<\/td>~9 mA (run mode)<\/td><\/tr>
Output Data<\/td>16-bit X and Y motion registers<\/td><\/tr>
Optics<\/td>Far-field lens, no focus adjustment needed<\/td><\/tr>
Interface<\/td>SPI<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div><\/div>\n<\/div>\n<\/div>\n\n\n\n
\n
\n
\n

WS2812B Addressable RGB LEDs (4-LED Array)<\/strong><\/strong><\/p>\n\n\n\n

The module includes a small array of four WS2812B RGB LEDs<\/strong> used primarily for status indication, mode alerts, and general debugging feedback. Each LED integrates its own controller, allowing all LEDs to be driven over a single data line. This keeps wiring minimal and simplifies firmware control, especially during system diagnostics and calibration.<\/p>\n\n\n\n

Specifications<\/strong><\/h4>\n\n\n\n
Parameter<\/strong><\/td>Value<\/strong><\/td><\/tr>
LED Count<\/td>4<\/td><\/tr>
Package<\/td>2020 RGB + controller<\/td><\/tr>
Typical Current<\/td>~12 mA per color channel<\/td><\/tr>
Control<\/td>Single-wire serial protocol<\/td><\/tr>
Notes<\/td>Individually addressable for multi-color status patterns<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>
\"neopixel<\/figure><\/div>\n<\/div>\n<\/div>\n\n\n\n

<\/span>Sensors Overview<\/strong><\/span><\/h2>\n\n\n\n
\n
\n
\n

SPI Interface – Optical Flow Sensor (PMW3901)<\/strong><\/strong><\/p>\n\n\n\n

The PMW3901 optical flow sensor<\/strong> uses a dedicated SPI interface for high-speed motion data transfer. This SPI bus is reserved exclusively for the optical flow sensor, allowing continuous and deterministic access to X and Y displacement data without interference from other peripherals.<\/p>\n\n\n\n

Signal<\/strong><\/td>Function<\/strong><\/td>ESP32-S3 GPIO<\/strong><\/td><\/tr>
MISO<\/td>SPI data from PMW3901<\/td>GPIO37<\/td><\/tr>
CLK<\/td>SPI clock<\/td>GPIO36<\/td><\/tr>
MOSI<\/td>SPI data to PMW3901<\/td>GPIO35<\/td><\/tr>
CS<\/td>Chip select<\/td>GPIO42<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>
\"pmw3901<\/figure><\/div>\n<\/div>\n<\/div>\n\n\n\n
\n
\n
\"vl53l1x<\/figure>
\n

I\u00b2C1 Interface – Time-of-Flight Sensor<\/strong><\/strong><\/p>\n\n\n\n

The VL53L1X Time-of-Flight distance sensor<\/strong> is connected to a separate I\u00b2C bus (I\u00b2C1). Using a dedicated I\u00b2C channel for height measurement isolates ranging traffic from other I\u00b2C devices and improves measurement stability, particularly during fast control loop updates in altitude-hold modes.<\/p>\n\n\n\n

Signal<\/strong><\/td>Function<\/strong><\/td>ESP32-S3 GPIO<\/strong><\/td><\/tr>
SCL1<\/td>I\u00b2C clock<\/td>GPIO41<\/td><\/tr>
SDA1<\/td>I\u00b2C data<\/td>GPIO40<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div><\/div>\n<\/div>\n<\/div>\n\n\n\n
\n
\n
\n

I\u00b2C0 Interface – IMU, Barometer, and Magnetometer<\/strong><\/strong><\/p>\n\n\n\n

The primary I\u00b2C bus (I\u00b2C0) is shared between the LiteWing drone\u2019s onboard IMU and the optional expansion sensors provided on the Flight Positioning Module. This shared bus connects the onboard MPU6050 IMU<\/strong> along with the unpopulated footprints for the MS5611 barometric pressure sensor<\/strong> and HMC5883L magnetometer<\/strong>. <\/p>\n\n\n\n

Important<\/strong>: The firmware support for the barometer and magnetometer is still under development; the electrical connections are already in place for users who wish to populate the components and extend functionality through custom firmware. By default, the MS5611 and HMC5883L will not be soldered with the LiteWing drone position module. <\/p>\n\n\n\n

Signal<\/strong><\/td>Function<\/strong><\/td>ESP32-S3 GPIO<\/strong><\/td><\/tr>
SCL<\/td>I\u00b2C clock<\/td>GPIO10<\/td><\/tr>
SDA<\/td>I\u00b2C data<\/td>GPIO11<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>
\"mpu6050<\/figure><\/div>\n<\/div>\n<\/div>\n\n\n\n

<\/span>PCB Design<\/strong> & Layout<\/span><\/h2>\n\n\n\n
\n
\n

The hardware design for the LiteWing Drone positioning module, along with the schematics is made open-source for people to try and experiment. All designs are under a CC license; you are free to build, modify, and share.<\/p>\n\n\n\n

\"pcb<\/figure>\n\n\n\n
Resource<\/strong><\/td>Description<\/strong><\/td>Link<\/strong><\/td><\/tr>
Circuit Diagrams<\/td>Circuit Diagrams<\/td><\/a>GitHub Repository<\/a><\/td><\/tr>
Gerber Files<\/td>Gerber Files are currently not made open<\/td>–<\/td><\/tr>
Firmware Binary Source<\/td>Firmware Binary Source<\/td><\/a>GitHub Repository<\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n<\/div>\n\n\n\n

Interactive BOM<\/h3>\n\n\n\n