Overview
Simple breadboard circuits and sample programs.
These pages walk through small circuits you can build on a breadboard, each with a wiring diagram and a sample program for R2P2-ESP32.
| Example | Class | What it does |
|---|---|---|
| LED Blink | GPIO |
Digital output |
| Switch Input | GPIO |
Digital input with pull-down |
| Piezo Speaker | PWM |
Play a scale |
| Voltage Divider | ADC |
Read an analog voltage |
| UART Echo | UART |
Serial communication |
| I2C OLED | I2C |
Draw on an OLED display |
| SPI Dot Matrix | SPI |
Light an 8×8 LED matrix |
What you need
- An ESP32-DevKitC running R2P2-ESP32 (see Quick Start or Build). Look-alike boards from other vendors may have a different pin assignment.
- A USB cable and a breadboard. A larger breadboard is easier for beginners.
- The parts listed on each page.
All pin numbers in these pages are ESP32 GPIO numbers, which are the numbers
printed as IO26, IO13, … on the DevKitC.
About the diagrams
The ESP32-DevKitC is wide: its two pin rows are 10 holes apart, so on a standard breadboard it leaves little or no room on one side. The diagrams therefore use a wider breadboard, with free holes beyond both pin rows. If you use a standard breadboard, wire to the pins with jumper wires instead, or use two breadboards.
The diagrams are drawn with BreadKit.
Running a program
Each example is a single Ruby file. Put it in /home on the device (via the Web
Terminal or rake "picomodem:put[...]", see File Transfer),
then run it from the shell with ./<file>.rb.
On this page