Pixhawk I2C Port Splitter / Expansion Board - 5 Ports with Cable

Specifications

• Bus Type: I2C (Inter-Integrated Circuit)

• Port Count: 5x 4-Pin Connectors (Wired in parallel)

• Connector Pitch: 1.25mm (Standard for APM/Pixhawk 2.4.8)

• Dimensions: 33.6mm (Length) x 12.7mm (Width)

• Circuit Type: Passive Breakout / Hub (No active logic)

• Cable: 4-Wire Multi-color (Red, Black, Yellow, Green)

Key Applications and Projects

• Advanced UAV Builds: Connecting a primary GPS/Compass, a secondary redundant backup compass, and a digital airspeed sensor to a single Pixhawk controller.

• Custom Sensor Arrays: Adding environmental monitoring I2C sensors alongside flight-critical I2C hardware on custom robotic rovers.

• Status Indicators: Wiring an external I2C RGB LED module or an OLED screen to view drone telemetry statuses without needing a computer connection.

Unlock New Capabilities (Project Evolution) The Autonomous Fixed-Wing Mapper: If you are building a fixed-wing drone for aerial mapping, you need multiple streams of telemetry. Evolve your build! Use this expansion board to connect a digital airspeed sensor (crucial for precise throttle control to prevent stalling), an external compass (to escape the magnetic interference of your motor), and an I2C OLED screen. You can verify your pre-flight checks and satellite lock directly on the fuselage without ever opening your laptop or pulling out a telemetry radio!

PACKAGE INCLUDED

• 1 x 5-Port I2C Expansion Board

• 1 x 4-Wire Connection Cable (Pre-crimped 4-pin connectors on both ends)

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What is an I2C expansion board used for? It is used to split a single I2C port into multiple ports. Since I2C devices use unique addresses, multiple sensors can communicate over the same two data lines (SDA and SCL).

2. Does it matter which port I plug the flight controller into? No. Because all five ports on the circuit board are wired in parallel, they are completely identical. You can use any port as the "Input" from the flight controller.

3. Can I plug in two identical I2C devices? Generally, no. If you plug in two identical devices (like two of the exact same compasses), they will have the same hardware address. This causes an address conflict, and the flight controller won't be able to communicate with either of them.

4. How do I fix an I2C address conflict? Many I2C sensors have a solder jumper on their circuit board that allows you to change their I2C address (e.g., from 0x3C to 0x3D). If you change the address of one device, you can use them both on this expansion board.

5. Do I need to provide extra power to this board? No. This is a passive board. It draws 5V or 3.3V power (VCC) directly from the flight controller's I2C port and distributes it to the attached peripherals.

6. What connector type does this board use? It uses a 1.25mm pitch 4-pin connector. This is the standard connector type used on the APM 2.6, APM 2.8, and the popular Pixhawk 2.4.8 flight controllers.

7. Is this board an active hub or a passive splitter? It is a purely passive splitter. There are no microchips or logic gates on this board; it simply connects the pins of all five ports together.

8. Will this work with a Pixhawk 4 or Cube Orange? You must check your specific flight controller's connector type. Newer Pixhawk variants (like the Pixhawk 4) often use JST-GH connectors, while this board typically ships with connectors suited for older Molex Picoblade / JST 1.25mm standards.

9. What do the four wires in the cable represent? While wire colors can vary, they represent the four lines required for I2C: VCC (Power), GND (Ground), SCL (Serial Clock), and SDA (Serial Data).

10. How many total devices can I connect? The board has 5 ports. One port is used to connect to the flight controller, leaving 4 ports available for your I2C devices.

11. Can I daisy-chain two of these boards together? Physically, yes. However, adding too many wires and devices increases the capacitance on the I2C bus, which can degrade the signal and cause sensor dropouts. It is best to keep I2C wire runs as short as possible.

12. What are the exact dimensions of the board? The printed circuit board measures 33.6mm in length and 12.7mm in width.

13. Will this work with an Arduino or Raspberry Pi? Yes, the I2C protocol is universal. However, you will likely need to cut one end of the included cable and crimp standard DuPont connectors onto the wires to plug it into an Arduino's header pins.

14. Do the cable colors match the pinout standardized colors? Not always. Never rely solely on wire color (Red is usually VCC, Black is GND). Always trace the pinout from your flight controller's manual to ensure VCC aligns with VCC on your sensor to avoid damaging your equipment.

15. Does this board process or filter the data? No. It does not contain any pull-up resistors or data filters. It is simply a physical wire bridge.

16. Can I use this board to split a UART or Serial port (Telemetry)? No. While a telemetry port also uses 4 pins (VCC, GND, TX, RX), UART is a point-to-point protocol. If you use this board to split a TX line to multiple devices, the data signals will collide and become corrupted.

17. How should I mount this to my drone? Because the board does not have mounting holes, the best method is to use a small square of double-sided foam mounting tape to stick it to your drone's frame or power distribution board cover.

18. Will using this hub increase the latency of my sensors? No, the electrical connection is virtually instantaneous. Any latency would solely be due to the flight controller having to poll a higher number of devices via software.

19. Are the pins on the board through-hole or SMD? The 4-pin connectors are surface-mounted (SMD) to the PCB. You should avoid pulling violently on the cables, as excessive force could rip the plastic connector off the circuit board.

20. Why do I need an external compass if my Pixhawk has an internal one? Internal compasses are heavily affected by the electromagnetic interference generated by the drone's power distribution board and spinning motors. Mounting an external compass high up on a GPS mast and connecting it via this I2C board guarantees clean, interference-free heading data.