ESP32 Servo controllable via HTTP JSON API / web browser

This sketch for PlatformIO allows you to use the ESP32 as a Servo controller (servo on pin D25) that connects to Wifi and can be controller using a simple HTTP API. The webserver is implemented using *ESPAsyncWebserver.*Also see ESP32 minimal JSON webserver example for PlatformIO (ESPAsyncWebserver) in case you are not familiar with that library. This example is not a finished application but a minimal starting point to build your own application.

main.cpp

#include <Arduino.h>
#include <Arduino.h>
#include <WiFi.h>
#include <ESP32Servo.h>

#include <ESPAsyncWebServer.h>
#include <ArduinoJson.h>

AsyncWebServer server(80);

/**
 * Wait for WiFi connection, and, if not connected, reboot
 */
void waitForWiFiConnectOrReboot(bool printOnSerial=true) {
  uint32_t notConnectedCounter = 0;
  while (WiFi.status() != WL_CONNECTED) {
      delay(100);
      if(printOnSerial) {
        Serial.println("Wifi connecting...");
      }
      notConnectedCounter++;
      if(notConnectedCounter > 50) { // Reset board if not connected after 5s
          if(printOnSerial) {
            Serial.println("Resetting due to Wifi not connecting...");
          }
          ESP.restart();
      }
  }
  if(printOnSerial) {
    // Print wifi IP addess
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());
  }
}

Servo servo;

void setup() {
  ESP32PWM::allocateTimer(0);
  ESP32PWM::allocateTimer(1);
  ESP32PWM::allocateTimer(2);
  ESP32PWM::allocateTimer(3);

  Serial.begin(115200);

  WiFi.config(INADDR_NONE, INADDR_NONE, INADDR_NONE);
  WiFi.setHostname("ESP-Servo");

  WiFi.begin("MyWifiSSID", "MyWifiPassword");
  waitForWiFiConnectOrReboot();

  // Attach servo to pin 25
  servo.attach(25, 1000, 2000);
  
  // Configure HTTP routes
  server.on("/api/set-servo", HTTP_GET, [](AsyncWebServerRequest *request) {
      float value = request->arg("value").toFloat();
      servo.write(value);
      // Send {status: "ok"}
      AsyncResponseStream *response = request->beginResponseStream("application/json");
      DynamicJsonDocument json(1024);
      json["status"] = "ok";
      serializeJson(json, *response);
      request->send(response);
  });
  
  // Start webserver
  server.begin();
}

void loop() {
}

platformio.ini

[env:nodemcu-32s]
platform = espressif32
board = nodemcu-32s
framework = arduino
monitor_speed = 115200
lib_deps =
    ESP Async [email protected]
    [email protected]
    ESP32Servo

How to use

Insert your Wifi credentials in the line

WiFi.begin("MyWifiSSID", "MyWifiPassword");

and upload the firmware. Now open http://[ip address of the ESP32]/api/set-servo?value=0.0. Note that in the current version of the firmware, you **can not use value=10**but you must use value=10.0.