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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.

Intermediate15 min115200 baud

Board

ESP32

3V3

GND

CMD

CLK

Fig. 1. Pins this project uses on the ESP32-DevKitC V4, 38 pin. USB connector at the bottom.

Wiring

Nothing to wire. This one runs on the bare board.

Tested on this board

Not run on this board yet. Treat the wiring and code as a first draft.

Firmware, Arduino sketch for ESP32 Dev Module

#include <WiFi.h>
#include <ESPmDNS.h>
#include <ArduinoOTA.h>

const char* WIFI_NAME = "your-network";
const char* WIFI_PASS = "your-password";
const char* OTA_NAME = "esp32-bench";  // the board appears as esp32-bench.local
const char* OTA_PASS = "change-me";    // asked for on every network upload

unsigned long lastBeat = 0;

void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_NAME, WIFI_PASS);
  Serial.printf("wifi joining %s\n", WIFI_NAME);
  while (WiFi.waitForConnectResult() != WL_CONNECTED) {
    Serial.println("wifi failed, retrying in 5 s");
    delay(5000);
    WiFi.begin(WIFI_NAME, WIFI_PASS);
  }

  ArduinoOTA.setHostname(OTA_NAME);
  ArduinoOTA.setPassword(OTA_PASS);
  ArduinoOTA
    .onStart([]() { Serial.printf("ota start: %s\n", ArduinoOTA.getCommand() == U_FLASH ? "sketch" : "filesystem"); })
    .onProgress([](unsigned int done, unsigned int total) { Serial.printf("ota %u percent\r", done * 100 / total); })
    .onEnd([]() { Serial.println("\nota done, restarting"); })
    .onError([](ota_error_t error) { Serial.printf("ota error %u\n", error); });
  ArduinoOTA.begin();
  Serial.printf("ota ready: %s.local at %s\n", OTA_NAME, WiFi.localIP().toString().c_str());
}

void loop() {
  ArduinoOTA.handle();  // call often: uploads only happen while this runs

  if (millis() - lastBeat > 10000) {
    lastBeat = millis();
    Serial.printf("up %lu s, rssi %d dBm\n", millis() / 1000, WiFi.RSSI());
  }
}

3V3

GND

3V3

RST

GND

Fig. 1. Pins this project uses on the ESP32-S3-DevKitC-1, 44 pin. USB connector at the bottom.

Wiring

Nothing to wire. This one runs on the bare board.

Tested on this board

Not run on this board yet. Treat the wiring and code as a first draft.

Firmware, Arduino sketch for ESP32S3 Dev Module

#include <WiFi.h>
#include <ESPmDNS.h>
#include <ArduinoOTA.h>

const char* WIFI_NAME = "your-network";
const char* WIFI_PASS = "your-password";
const char* OTA_NAME = "esp32-bench";  // the board appears as esp32-bench.local
const char* OTA_PASS = "change-me";    // asked for on every network upload

unsigned long lastBeat = 0;

void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_NAME, WIFI_PASS);
  Serial.printf("wifi joining %s\n", WIFI_NAME);
  while (WiFi.waitForConnectResult() != WL_CONNECTED) {
    Serial.println("wifi failed, retrying in 5 s");
    delay(5000);
    WiFi.begin(WIFI_NAME, WIFI_PASS);
  }

  ArduinoOTA.setHostname(OTA_NAME);
  ArduinoOTA.setPassword(OTA_PASS);
  ArduinoOTA
    .onStart([]() { Serial.printf("ota start: %s\n", ArduinoOTA.getCommand() == U_FLASH ? "sketch" : "filesystem"); })
    .onProgress([](unsigned int done, unsigned int total) { Serial.printf("ota %u percent\r", done * 100 / total); })
    .onEnd([]() { Serial.println("\nota done, restarting"); })
    .onError([](ota_error_t error) { Serial.printf("ota error %u\n", error); });
  ArduinoOTA.begin();
  Serial.printf("ota ready: %s.local at %s\n", OTA_NAME, WiFi.localIP().toString().c_str());
}

void loop() {
  ArduinoOTA.handle();  // call often: uploads only happen while this runs

  if (millis() - lastBeat > 10000) {
    lastBeat = millis();
    Serial.printf("up %lu s, rssi %d dBm\n", millis() / 1000, WiFi.RSSI());
  }
}

GND

3V3

GND

RST

GND

Fig. 1. Pins this project uses on the ESP32-C3-DevKitM-1, 30 pin. USB connector at the bottom.

Wiring

Nothing to wire. This one runs on the bare board.

Tested on this board

Not run on this board yet. Treat the wiring and code as a first draft.

Firmware, Arduino sketch for ESP32C3 Dev Module

#include <WiFi.h>
#include <ESPmDNS.h>
#include <ArduinoOTA.h>

const char* WIFI_NAME = "your-network";
const char* WIFI_PASS = "your-password";
const char* OTA_NAME = "esp32-bench";  // the board appears as esp32-bench.local
const char* OTA_PASS = "change-me";    // asked for on every network upload

unsigned long lastBeat = 0;

void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_NAME, WIFI_PASS);
  Serial.printf("wifi joining %s\n", WIFI_NAME);
  while (WiFi.waitForConnectResult() != WL_CONNECTED) {
    Serial.println("wifi failed, retrying in 5 s");
    delay(5000);
    WiFi.begin(WIFI_NAME, WIFI_PASS);
  }

  ArduinoOTA.setHostname(OTA_NAME);
  ArduinoOTA.setPassword(OTA_PASS);
  ArduinoOTA
    .onStart([]() { Serial.printf("ota start: %s\n", ArduinoOTA.getCommand() == U_FLASH ? "sketch" : "filesystem"); })
    .onProgress([](unsigned int done, unsigned int total) { Serial.printf("ota %u percent\r", done * 100 / total); })
    .onEnd([]() { Serial.println("\nota done, restarting"); })
    .onError([](ota_error_t error) { Serial.printf("ota error %u\n", error); });
  ArduinoOTA.begin();
  Serial.printf("ota ready: %s.local at %s\n", OTA_NAME, WiFi.localIP().toString().c_str());
}

void loop() {
  ArduinoOTA.handle();  // call often: uploads only happen while this runs

  if (millis() - lastBeat > 10000) {
    lastBeat = millis();
    Serial.printf("up %lu s, rssi %d dBm\n", millis() / 1000, WiFi.RSSI());
  }
}

Parts

Quantity	Part	Where to buy
1×	ESP32 dev board	Buy at Amazon
1×	USB cable for the first upload

Amazon buy links may include an Associates tag, and this site may earn a commission from qualifying Amazon purchases at no extra cost to you. Adafruit links are direct.

Libraries

WiFi (built in), ArduinoOTA (built in), ESPmDNS (built in)

Load it

In the Arduino IDE, install the esp32 board package and pick the board named above the sketch.
Paste the sketch, choose the board's port and upload. Hold BOOT if the upload stalls at Connecting.
Close the IDE's serial monitor, then open the bench here to watch the output.

Field notes

The first upload has to go over USB. After that, the board shows up as a network port named esp32-bench in the Arduino IDE's port list, and Upload sends the sketch over Wi-Fi.
Every sketch you upload over the air must include the OTA code too. Leave it out and the next update needs a USB cable again.
Network uploads need a partition scheme with two app slots, such as the default. Huge APP and No OTA have only one slot and cannot take an update.
Your computer and the board must be on the same network, and some guest or mesh networks block the mDNS lookups the IDE uses to find the board.
In PlatformIO, set upload_protocol = espota, upload_port = esp32-bench.local and upload_flags = --auth=change-me.
To update from a browser instead, the core's HTTPUpdateServer example serves an upload page for the compiled .bin file.

Not tested yet

Not tested on hardware yet. Compiles for every board listed with Arduino-ESP32 core 3.3.12.

Open the bench at 115200 baud

Built it? Send a build report with your board and what the serial port printed. Working reports become the "Tested on this board" entries above.