1.5.8 - Launcher Wiring

Custom Electronics: This step adds an Arduino Pro Micro as a sub-controller so the XRP can drive the high-RPM launcher motors.

Caution

Stop! Only continue if you have completed the physical assembly of the Ping Pong bot.
If not, go back to the Assembly Guide first.

Note

Prerequisites Your base XRP should already be built and wired.
This is a custom add-on required for the high-RPM launcher motors. It also leaves expansion options for future add-ons.

What You Will Be Doing

You are adding a small “smart controller” (Arduino Pro Micro) and a motor driver (L9110S) so the launcher motors can spin fast enough to shoot a ping pong ball.

The XRP does not power the launcher motors directly. It only sends a simple command. The Arduino reads that command and tells the motor driver how much power to send to the two high-RPM motors.

Note

The FRC Big Picture This is a miniature version of how a real FRC robot works.

In competition robots, the RoboRIO / SystemCore (your XRP) does not power the motors directly. It sends a low-voltage signal to a smart motor controller (your Arduino + L9110S). That controller then pulls high current straight from the battery to spin the motors.

Wiring Diagram

Use the live wiring diagram below. It shows every connection you need to make.

Open Launcher Wiring Diagram

Caution

Power Off First Make sure your robot is powered off and the battery is unplugged before making any of these connections.

Master Wiring Table

Follow this table exactly.

Connection Group	From (Component : Pin)	To (Component : Pin)	Logic/Voltage	Purpose
Control Signal	XRP SERVO2: Signal (IO17)	Pro Micro: Pin 2	PWM	Signal from WPILib
Common Ground	L9110S: Ground (GND)	XRP SERVO2: Ground (GND)	0V	Completes the circuit
Arduino Power	XRP SERVO2: Power (Center/Red)	Pro Micro: RAW	5V	Powers the Arduino
Motor A Drive	Pro Micro: Pin 5 & 6	L9110S: A-1A & A-1B	5V Logic	Speed/Direction A
Motor B Drive	Pro Micro: Pin 9 & 10	L9110S: B-1A & B-1B	5V Logic	Speed/Direction B
Motor Power	XRP Battery: Red Wire	L9110S: VCC	6V Battery	High Current Supply

Quick Summary of What Each Part Does

• Arduino Pro Micro — Receives the simple “shoot” command from the XRP and turns it into the two signals the motor driver needs.
• L9110S Motor Driver — Acts as a high-current switch. It takes power directly from the battery and only lets it through when the Arduino tells it to.
• High-RPM Motors — Get the power they need to launch the ball (connected through the L9110S).

Once all wires match the table and the wiring diagram, you’re ready to continue.