ESP32-DevKitC V4, 38 pin pinout

ESP32 board. Pick ESP32 Dev Module in the Arduino IDE. 13 of its header GPIOs are free of boot, flash and USB duties.

Every pin

Pads in order from the top, with the USB connector at the bottom. Numbers are GPIO numbers, which is what sketches use.

The ESP32 chip

Compare every ESP32 chip · ESP32 datasheet

Projects for this board

• ProbeHarbor probe Prebuilt sensor firmware from the ProbeHarbor project. Flash it from this page, then it finds a temperature sensor by itself and posts a reading every minute.
• Blink and heartbeat Toggle the LED on GPIO 2 and print a tick every second. The first thing to flash on any new board.
• Wi-Fi scanner List nearby networks with signal strength and channel every ten seconds. A quick radio health check.
• I2C bus scanner Probe every address on the I2C bus and report what answers. Run it before trusting any sensor wiring.
• DHT22 climate logger Read temperature and humidity every two seconds and print them as a log line.
• SSD1306 OLED status Drive a 128 by 64 I2C OLED and show an uptime counter. The base for any small status display.
• HC-SR04 distance Measure distance with an ultrasonic sensor. The echo pin is 5 V, so it goes through a divider.
• Deep sleep, button wake Sleep at microamp current and wake on a button press. A boot counter survives in RTC memory.
• Web page LED switch Join your Wi-Fi, serve a one-button page and switch GPIO 2 from any phone on the network.
• Touch piano Turn four bare wires into touch keys. Each touch prints a note, and an optional buzzer plays it.
• ESP-NOW pair Two boards talk directly over the Wi-Fi radio, with no router. Each sends a counter and prints what the other sends.
• NeoPixel effects Drive a strip or stick of WS2812 LEDs through a color wipe, a rainbow and a theater chase.
• Home Assistant temperature Publish a DS18B20 reading over MQTT every 30 seconds. Home Assistant finds the sensor by itself through MQTT discovery.
• Bluetooth LE scanner List nearby Bluetooth LE devices with their signal strength every ten seconds: phones, watches, beacons and sensors.
• Over-the-air updates Upload new firmware over Wi-Fi with ArduinoOTA, so a board in a box on the shelf never needs a USB cable again.
• Battery deep-sleep sensor Wake every five minutes, read a DS18B20 and the battery voltage, then go back to deep sleep. A boot counter survives in RTC memory.
• Relay and servo control Move a hobby servo to any angle and switch a relay module on and off by typing commands on the bench.
• E-paper temperature card Show a DS18B20 reading on a 2.9 inch e-paper panel that keeps its image with the power off, refreshing only when the value changes.
• BME280 web dashboard The board serves its own web page with live temperature, humidity and pressure and a chart that grows every two seconds.
• Wi-Fi setup portal No passwords in the sketch: the board opens its own setup network with a page to pick your Wi-Fi, saves it, and joins it from then on.
• DS18B20 to ProbeHarbor Read a waterproof DS18B20 probe and post the temperature to ProbeHarbor once a minute.
• DS18B20 with Wi-Fi portal The same DS18B20 probe, but Wi-Fi is set from a phone through a captive portal instead of being compiled in.
• Door contact to ProbeHarbor A reed switch on a door. Posts open or shut once a minute and right away when it changes.
• Leak pads to ProbeHarbor Two bare contacts on the floor. Water between them posts a leak, which ProbeHarbor turns into an alert.
• Power sense to ProbeHarbor Report whether a circuit has power. ProbeHarbor raises a power-off alert when it drops and a recovery notice when it returns.
• MAX31855 thermocouple to ProbeHarbor A K-type thermocouple through a MAX31855 amplifier, for temperatures a DS18B20 cannot survive.
• MAX6675 thermocouple to ProbeHarbor The lower-cost MAX6675 thermocouple module, posting a temperature once a minute.