Overview

The MATRIX Joystick 2 (MJ2) is a 2.4GHz wireless remote controller designed specifically for the MATRIX series of robots, including the Mini R4. It offers a variety of control elements, such as dual-axis joysticks and multiple buttons, enabling intuitive and flexible remote control of a robot’s movements and

functions. MJ2 connects to the MATRIX Mini R4 controller via a matching wireless receiver adapter board, using the SPI communication protocol. This

controller is an ideal choice for projects involving complex robot remote control and interactive game control.

Feature

Wireless Technology: 2.4GHz wireless communication for stable remote control.

Main Controls:

• Dual Analog Joysticks (“mushroom heads”): One on each side, each providing X and Y axis analog values (0-255) for precise direction and speed control.

• D-pad: Digital directional input for up, down, left, and right.

• Four Primary Action Buttons: △ (Triangle), ○ (Circle), X (Cross), □ (Square)

• Shoulder Buttons: L1, L2, R1, R2

• Other Buttons: SELECT, START, MODE, and clickable L3 (left stick) and R3 (right stick)

Power: Powered by two AAA batteries.

Pairing: Can pair with its dedicated receiver; usually pre-paired at the factory.

Operation Modes: Supports Analog (default) and Digital modes

• Important Note: To ensure correct joystick signal readings, we recommend remaining in the default Analog mode. Digital mode may cause signal transmission issues is accidentally switched.

LED Status Indication

The MJ2 and its wireless receiver are equipped with LED indicators to help users quickly determine their current working status.

Controller LED Status:

• Solid light: Controller is receiving and in analog mode (default).

• Flashes every 0.5 secs: Controller is receiving, but in digital mode.

• Flashes every 0.25 secs: Low battery warning.

• Flashes every 0.1 secs: Pairing mode. Returns to default after 3 seconds.

• Flashes every 1 sec: Standby mode after 15 minutes of inactivity.

Receiver LED Status:

• Off: No signal or incorrect ID.

• Solid Light: Receiving signal, joystick in analog mode.

• Flashes every 0.5 secs: Receiving signal, joystick in digital mode. (Default)

• Flashes every 0.125: Pairing mode. Restores to default after 10 seconds.

Application

• Remote Control: Real-time control of SumoBot or task-based robots in competitions like WRO, MARC, or for custom vehicle projects.

• Robotic Arms: Precise remote control of multi-axis robotic arms (e.g., gripping, moving).

• Interactive Game Controller: Combine Mini R4 with MH2 as input handles for custom games.

• Remote Equipment Control: Wireless operation of display props, small automation devices, etc.

• Education and Training:

1. Practice precise motor speed and direction control.

2. Design button combinations to trigger different robot behaviors and train logical thinking.

Electrical Characteristics

Pinout

MJ2 connects to the MATRIX Mini R4 controller through its adapter board. The adapter translates control signals into SPI protocol data readable by the Mini R4.

Receiver adapter board pin description and Mini R4 connection:

The following table lists the main signal pins of the MJ2 wireless receiver adapter board, their corresponding SPI functions, and the recommended digital interface for connection to the MATRIX Mini R4.