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Sonar:bit is a 3-wire ultrasonic module with the working voltage between 3-5V. It is available to be used to 3.3V or 5V micro-controller system. With only one 3-wire(GVS) cable, it can work properly. Compared to the normal 4-wire ultrasonic module, it has saved one IO port. The measurement range of sonar:bit is 4cm-400cm. It can output stable and accurate measurement data with ±1cm tolerance only. It's available for short distance measuring in robtics device, micro:bit and Arduino etc.

ELECFREAKS Octopus Sonar:bit)


The input voltage is 3V~5V, both micro:bit and Arduino are able to drive it.

Standard 3-GVS cable, occupy one IO port only.


Input VoltageDC 3-5V
Measurement Distance4-400cm
Size40.60× 51.60mm
Net Weight12g

Outlook and dimensions

Pins diagram

The probes send out and receive ultrasonic signals.

Main parts information

Emitting probes

The emmiting probes send out ultrasonic signals.

Receving probes

The receiving probes receive ultrasonic signals.

Chips MCU

Core controlling chips

Emitting signals driving chips

The transmitting signal driving chip is used to provide the transmitting ultrasonic signal for driving the ultrasonic transmitting probe.

Receiving signals driving chips

The receiving signal processing chip is used for receiving and processing the ultrasonic echo signal, and feeding back the processed signal to the main control chip.

G-V-S controlling port

G-V-S are used for the controlling of the sonar:bit by other devices.

Quick start

Materails required and connections diagram

Connect the sonar:bit to the P1 port of the iot:bit and the micro:bit to the computer.

Take iot:bit for an example

Step 1

Click “Advanced“ in the MakeCode drawer and click “Extentions“ to see more choices.

We need to add a package for programming, . Click “Extensions” in the bottom of the drawer and search with “” in the dialogue box to download it.

Note: If you met a tip indicating that the codebase will be deleted due to incompatibility, you may continue as the tips say or build a new project in the menu.

Step 2

In forever block, show the returned value from Sonar:bit in digit.



You may also download it directly below:


The distance between the ultrasonic module and the object is displayed on the micro:bit with unit in cm.

Relevant Projects

Technical File