Important Note
This entire repo was AI created - including all of the data within. The intent was to A) help me with my personal electronics inventory; and B) see how I could use AI to make that process a bit easier. DO NOT TRUST!

Circuit Playground Express

Overview

Circuit Playground Express is the next step towards a perfect introduction to electronics and programming. We’ve taken the original Circuit Playground Classic and made it even better! Not only did we pack even more sensors in, we also made it even easier to program with support for multiple programming environments.

Specifications

Microcontroller: ATSAMD21 ARM Cortex M0 Processor
Clock Speed: 48MHz
Operating Voltage: 3.3V
Flash Memory: Built-in flash + 2MB SPI Flash storage
Outer Diameter: ~50.6mm / ~2.0”
Weight: 8.9g

Key Features

Multiple Programming Options

Microsoft MakeCode: Block-based or JavaScript programming
CircuitPython: Python interpreter running on the board
Arduino IDE: Full Arduino IDE support with low-level access
Code.org CS Discoveries: Browser-based coding education

Enhanced Hardware

10x Mini NeoPixels: Full-color RGB LEDs with individual control
Motion Sensor: LIS3DH triple-axis accelerometer with tap detection
Temperature Sensor: Thermistor for ambient temperature
Light Sensor: Phototransistor (can also act as color/pulse sensor)
Sound Sensor: MEMS microphone for audio input
Mini Speaker: Class D amplifier with 7.5mm magnetic speaker
Infrared: Both receiver and transmitter for remote control

Connectivity and I/O

8x Alligator-Clip Pads: No soldering required
7x Capacitive Touch: Touch-sensitive input pads
1x True Analog Output: Real DAC output
Multiple PWM: Multiple PWM-capable outputs
I2C, UART: Hardware communication interfaces

Hardware Components

Sensors and Inputs

LIS3DH Accelerometer: 3-axis motion with tap and free-fall detection
Thermistor: Temperature sensing with wide range
Phototransistor: Light sensing with color detection capability
MEMS Microphone: High-quality audio input
Infrared Receiver: Receive remote control signals
Capacitive Touch: 7 touch-sensitive pads

Outputs and Indicators

10x NeoPixels: Individually addressable RGB LEDs
Class D Amplifier: High-quality audio output
Infrared Transmitter: Send remote control codes
Green ON LED: Power indicator
Red #13 LED: User programmable LED

User Interface

2x Push Buttons: Labeled A and B for user input

Pinout Diagram

Circuit Playground Express Pinout

Basic Wiring Examples

External LED Connection

CPX Pin A1 → LED Anode (long leg)
LED Cathode (short leg) → 220Ω Resistor → CPX GND

Note: Built-in NeoPixels available for most projects

Button/Switch Connection

CPX 3.3V → 10kΩ Pull-up Resistor → CPX Pin A2
CPX Pin A2 → Button → CPX GND

Code: digitalRead(A2) returns HIGH when not pressed, LOW when pressed

Servo Motor Connection

Servo Red Wire → CPX VOUT (5V power)
Servo Black/Brown Wire → CPX GND
Servo White/Orange Wire → CPX Pin A1 (PWM)

Note: Use VOUT for high-power devices like servos

I2C Device Connection

I2C Device VCC → CPX 3.3V
I2C Device GND → CPX GND
I2C Device SDA → CPX Pin A5 (SDA)
I2C Device SCL → CPX Pin A4 (SCL)

Note: Built-in pull-up resistors included

Analog Sensor Reading

Sensor Output → CPX Pin A1, A2, A3, A6, or A7
Sensor VCC → CPX 3.3V
Sensor GND → CPX GND

Code: analogRead(A1) returns 0-65535 (0-3.3V)

Alligator Clip Connections

No soldering required! Use alligator clips to connect:
- Conductive materials (fruit, water, foil)
- Breadboard components
- Sensors and actuators
- Educational experiments

Programming Examples

CircuitPython NeoPixel Rainbow

import board
import neopixel
import time
 
pixels = neopixel.NeoPixel(board.NEOPIXEL, 10, brightness=0.3)
 
def wheel(pos):
    if pos < 0 or pos > 255:
        return (0, 0, 0)
    if pos < 85:
        return (255 - pos * 3, pos * 3, 0)
    if pos < 170:
        pos -= 85
        return (0, 255 - pos * 3, pos * 3)
    pos -= 170
    return (pos * 3, 0, 255 - pos * 3)
 
while True:
    for j in range(255):
        for i in range(10):
            pixel_index = (i * 256 // 10) + j
            pixels[i] = wheel(pixel_index & 255)
        pixels.show()
        time.sleep(0.01)

CircuitPython Button and Sound

import board
import digitalio
import audioio
import audiocore
import time
 
# Set up buttons
button_a = digitalio.DigitalInOut(board.BUTTON_A)
button_a.direction = digitalio.Direction.INPUT
button_a.pull = digitalio.Pull.DOWN
 
button_b = digitalio.DigitalInOut(board.BUTTON_B)
button_b.direction = digitalio.Direction.INPUT
button_b.pull = digitalio.Pull.DOWN
 
# Set up speaker
speaker = audioio.AudioOut(board.SPEAKER)
 
while True:
    if button_a.value:
        print("Button A pressed!")
        # Play tone (requires audio file)
 
    if button_b.value:
        print("Button B pressed!")
 
    time.sleep(0.1)

CircuitPython Accelerometer

import board
import adafruit_lis3dh
import busio
import time
 
# Set up accelerometer
i2c = busio.I2C(board.ACCELEROMETER_SCL, board.ACCELEROMETER_SDA)
lis3dh = adafruit_lis3dh.LIS3DH_I2C(i2c)
 
while True:
    x, y, z = lis3dh.acceleration
    print(f"X: {x:6.2f} Y: {y:6.2f} Z: {z:6.2f} m/s^2")
 
    # Detect shake
    if abs(x) > 15 or abs(y) > 15 or abs(z) > 15:
        print("Shake detected!")
 
    time.sleep(0.1)

MakeCode Block Example (JavaScript)

// Button A controls NeoPixels
input.onButtonPressed(Button.A, function () {
  light.setAll(0xff0000); // Red
  music.playTone(262, music.beat(BeatFraction.Half));
});
 
// Button B controls NeoPixels
input.onButtonPressed(Button.B, function () {
  light.setAll(0x0000ff); // Blue
  music.playTone(523, music.beat(BeatFraction.Half));
});
 
// Shake detection
input.onGesture(Gesture.Shake, function () {
  light.showRing(`red red red red red red red red red red`);
  music.playMelody("C D E F G A B C5 ", 120);
});

Arduino Example

#include <Adafruit_CircuitPlayground.h>
 
void setup() {
  CircuitPlayground.begin();
  Serial.begin(9600);
}
 
void loop() {
  // Check buttons
  if (CircuitPlayground.leftButton()) {
    CircuitPlayground.setPixelColor(0, 255, 0, 0);  // Red
    CircuitPlayground.playTone(440, 500);
  }
 
  if (CircuitPlayground.rightButton()) {
    CircuitPlayground.setPixelColor(0, 0, 0, 255);  // Blue
    CircuitPlayground.playTone(880, 500);
  }
 
  // Read sensors
  float temp = CircuitPlayground.temperature();
  float light = CircuitPlayground.lightSensor();
 
  Serial.print("Temperature: ");
  Serial.print(temp);
  Serial.print("°C, Light: ");
  Serial.println(light);
 
  delay(100);
}

1x Slide Switch: Mode selection or on/off control
Reset Button: Manual reset and bootloader entry

Programming Platforms

Microsoft MakeCode

Block Programming: Drag-and-drop visual programming
JavaScript: Text-based programming option
Simulator: Test code without hardware
Web-Based: No software installation required
Educational: Perfect for beginners

CircuitPython

Python Interpreter: Real Python running on microcontroller
Interactive REPL: Live coding and debugging
File System: Access board as USB drive
Extensive Libraries: Large ecosystem of libraries
Rapid Development: Quick iteration and testing

Arduino IDE

Full Support: Complete Arduino IDE compatibility
Low-Level Access: Direct hardware control
C/C++ Programming: Traditional embedded programming
Library Ecosystem: Access to Arduino libraries
Advanced Features: For experienced developers

Code.org CS Discoveries

Curriculum Integration: Part of computer science education
Classroom Ready: Designed for educational environments
Progressive Learning: Structured learning progression
Teacher Resources: Comprehensive teaching materials

Pin Configuration

GPIO Pins (8 total)

A0: Analog input, digital I/O, capacitive touch
A1: Analog input, digital I/O, capacitive touch, true analog output
A2: Analog input, digital I/O, capacitive touch
A3: Analog input, digital I/O, capacitive touch
A4: Analog input, digital I/O, capacitive touch
A5: Analog input, digital I/O, capacitive touch
A6: Analog input, digital I/O, capacitive touch
A7: Analog input, digital I/O, capacitive touch

Power Pins

3.3V: Two power output pads
GND: Three ground pads
VBATT: Battery/USB voltage output

Communication

SDA/SCL: I2C communication (shared with GPIO)
TX/RX: UART communication (shared with GPIO)
Multiple PWM: Various pins support PWM output

Storage and Memory

SPI Flash (2MB)

CircuitPython Storage: Store code and libraries
File System: Appears as USB drive when connected
Data Logging: Store sensor data and logs
User Files: Images, sounds, configuration files

Built-in Flash

Program Storage: Store compiled programs
Bootloader: UF2 bootloader for easy programming
Multiple Programs: Switch between different programs

Applications

Educational Projects

STEM Learning: Science, technology, engineering, math
Programming Education: Learn coding with immediate feedback
Electronics Basics: Understand sensors and actuators
Creative Projects: Art, music, and interactive installations

Maker Projects

Wearable Electronics: Fashion and costume integration
Home Automation: Smart home sensors and controls
Robotics: Brain for robotic projects
IoT Devices: Internet-connected sensors and actuators

Professional Use

Rapid Prototyping: Quick concept development
Educational Tools: Teaching aids and demonstrations
Art Installations: Interactive art and exhibits
Product Development: Proof-of-concept development

Power Management

Power Sources

USB Power: 5V from micro USB connector
Battery Power: 3.7V LiPo or 3xAAA battery pack
Auto-Switching: Automatically selects power source
JST Connector: Standard battery connector

Power Consumption

Active Mode: Varies by program and LED usage
Sleep Modes: Low-power modes available
NeoPixel Control: Significant power when LEDs active
Sensor Power: Minimal additional current

Getting Started

MakeCode Setup

Open Browser: Go to makecode.adafruit.com
Select Board: Choose Circuit Playground Express
Drag Blocks: Create program with visual blocks
Download: Save .uf2 file to board
Test: Program runs immediately

CircuitPython Setup

Install CircuitPython: Download and install firmware
Connect USB: Board appears as CIRCUITPY drive
Edit Code: Modify code.py file
Save: Code runs automatically on save
Use REPL: Interactive Python shell

Arduino Setup

Install Arduino IDE: Download latest version
Add Board Package: Install Adafruit SAMD boards
Select Board: Choose “Adafruit Circuit Playground Express”
Install Libraries: Add Circuit Playground library
Upload Code: Compile and upload sketches

Advanced Features

Infrared Communication

Remote Control: Receive and transmit IR signals
Device Control: Control TVs, stereos, etc.
Communication: Send data between boards
Proximity Sensing: Detect nearby objects

Audio Processing

Sound Analysis: Analyze microphone input
Music Generation: Create tones and melodies
Voice Control: Simple voice recognition
Audio Effects: Process and modify sounds

Motion Detection

Orientation: Detect board orientation
Tap Detection: Respond to taps and knocks
Free-fall: Detect when board is dropped
Activity: Monitor movement and activity

Package Contents

1x Circuit Playground Express board
Pre-loaded CircuitPython firmware
Getting started documentation
Access to online resources and tutorials

Important Notes

Multiple Programming: Can switch between different programming environments
3.3V Logic: All I/O operates at 3.3V levels
File System: CircuitPython mode shows board as USB drive
Bootloader: Double-click reset for bootloader mode
Community: Large community with extensive resources

Advantages

Versatile Programming: Multiple programming options for different skill levels
Rich Hardware: Comprehensive sensor and output collection
Educational: Perfect for learning electronics and programming
No Soldering: Alligator clips eliminate soldering requirements
Rapid Development: Quick prototyping and iteration

Limitations

3.3V Only: Requires level shifting for 5V devices
Limited GPIO: Only 8 general-purpose I/O pins
Power Consumption: NeoPixels can consume significant power
Size Constraints: Round form factor limits some applications
Cost: More expensive than basic microcontrollers

Recommended Accessories

Alligator clip test leads for connections
3xAAA battery pack for portable power
USB cable for programming and power
Sensors and actuators for expansion
Breadboard and components for advanced projects

BinKey

Explorer

Circuit Playground Express

Circuit Playground Express

Overview

Specifications

Key Features

Multiple Programming Options

Enhanced Hardware

Connectivity and I/O

Hardware Components

Sensors and Inputs

Outputs and Indicators

User Interface

Pinout Diagram

Basic Wiring Examples

External LED Connection

Button/Switch Connection

Servo Motor Connection

I2C Device Connection

Analog Sensor Reading

Alligator Clip Connections

Programming Examples

CircuitPython NeoPixel Rainbow

CircuitPython Button and Sound

CircuitPython Accelerometer

MakeCode Block Example (JavaScript)

Arduino Example

Programming Platforms

Microsoft MakeCode

CircuitPython

Arduino IDE

Code.org CS Discoveries

Pin Configuration

GPIO Pins (8 total)

Power Pins

Communication

Storage and Memory

SPI Flash (2MB)

Built-in Flash

Applications

Educational Projects

Maker Projects

Professional Use

Power Management

Power Sources

Power Consumption

Getting Started

MakeCode Setup

CircuitPython Setup

Arduino Setup

Advanced Features

Infrared Communication

Audio Processing

Motion Detection

Package Contents

Important Notes

Advantages

Limitations

Recommended Accessories

Graph View

Table of Contents

Backlinks