Overview

The Pimoroni Explorer HAT Pro is a beginner-friendly, multifunction expansion board designed for the Raspberry Pi. Fitting directly onto the 40-pin GPIO header, it turns the Pi into a prototyping and robotics workstation by adding motor drivers, analog sensing, 5V buffered outputs, touch inputs, and mini breadboard prototyping space.

The HAT integrates three specialized ICs:

1. Texas Instruments DRV8833: Dual H-bridge motor driver capable of driving two DC motors or one 4-wire stepper motor at up to $1.2\text{ A}$ peak per channel.
2. Texas Instruments ADS1015: 4-channel 12-bit Analog-to-Digital Converter (ADC) allowing 5V analog sensors (potentiometers, light sensors, distance sensors) to be read by the Pi over $I^2C$.
3. Microchip CAP1204: 4-channel capacitive touch controller driving 4 touch pads (labeled 1, 2, 3, 4) on the HAT surface.

Quick reference

Onboard ICs & $I^2C$ Addresses

• ADS1015 ADC: $I^2C$ address 0x48 (Reads analog channels 1, 2, 3, 4).
• CAP1204 Touch Controller: $I^2C$ address 0x28 (Reads touch pads 1, 2, 3, 4 and alligator clip pads).
• DRV8833 Motor Driver: Controlled directly via Pi GPIO pins:
  • Motor 1: GPIO 19 (M1+) & GPIO 20 (M1-)
  • Motor 2: GPIO 21 (M2+) & GPIO 26 (M2-)

Pinout & Connector Headers

Screw Terminals & 0.1" Female Headers

Specifications

Python Software Installation & Architecture

Pimoroni provides an official Python library (explorerhat):

sudo apt-get update
sudo apt-get install python3-pip
sudo pip3 install explorerhat

Python Code Example

import explorerhat
import time

print("Explorer HAT Pro Test Script")

# Light status LEDs
explorerhat.light.blue.on()
explorerhat.light.green.on()

# Read 5V Analog input channel 1
analog_val = explorerhat.analog.one.read()
print(f"Analog Channel 1 Voltage: {analog_val:.2f} V")

# Run DC Motor 1 forward at 80% speed for 2 seconds
print("Running Motor 1 forward...")
explorerhat.motor.one.forwards(80)
time.sleep(2)
explorerhat.motor.one.stop()

# Define capacitive touch callback function
def touch_callback(channel, event):
    print(f"Touch pad {channel} was {event}!")
    explorerhat.light.red.toggle()

# Register callback for touch pad 1
explorerhat.touch.one.pressed(touch_callback)

print("Touch pads active. Press Ctrl+C to exit.")
try:
    while True:
        time.sleep(1)
except KeyboardInterrupt:
    explorerhat.light.off()
    explorerhat.motor.stop()

Common mistakes

• Connecting high-voltage motors ($>5\text{V}$): The Explorer HAT motor driver is powered directly from the Raspberry Pi's 5V power bus. Do not connect motors that draw $>5\text{V}$ or $>1.2\text{ A}$, as excessive current draw causes Raspberry Pi brownout resets.
• Forgetting common ground for external sensors: When powering external sensors from an external power supply, ensure external GND is tied to the Explorer HAT GND header pin.

Notes

• Explorer HAT vs Explorer HAT Pro: The Pro version adds the DRV8833 dual motor driver, 4 5V-tolerant analog inputs, and 4 5V-buffered outputs; the standard non-Pro version lacks motor control and analog inputs.