10. Remote Buzzer Control

Read a command from PxServ and control a low-current active buzzer module. If the command cannot be read, the output returns to its safe off state.

Level: Beginner · Time: 25 minutes

Parts and wiring

ESP32 DevKit V1 and 3.3 V-compatible active buzzer module

Buzzer module	ESP32
VCC	3V3
I/O or SIG	GPIO 23
GND	GND

Do not connect a bare or high-current buzzer directly to GPIO; use a suitable transistor driver.

PxServ keys

Key	Value
`buzzer/command`	`0` / `1`
`buzzer/status`	Applied device state

Create the command with value 0 before starting.

Complete sketch


#include <PxServ.h>
 
const char* WIFI_SSID = "your_wifi_ssid";
const char* WIFI_PASSWORD = "your_wifi_password";
const char* PXSERV_API_KEY = "your_pxserv_api_key";
const int BUZZER_PIN = 23;
 
PxServ client(PXSERV_API_KEY);
 
void setBuzzer(bool enabled) {
  digitalWrite(BUZZER_PIN, enabled ? HIGH : LOW);
  client.setData("buzzer/status", enabled ? "1" : "0");
}
 
void setup() {
  Serial.begin(115200);
  pinMode(BUZZER_PIN, OUTPUT);
  digitalWrite(BUZZER_PIN, LOW);
  PxServ::connectWifi(WIFI_SSID, WIFI_PASSWORD);
  setBuzzer(false);
}
 
void loop() {
  PxServ::Callback command = client.getData("buzzer/command");
  if (command.status == 200) {
    bool enabled = command.data == "1";
    setBuzzer(enabled);
    Serial.println(enabled ? "Buzzer on" : "Buzzer off");
  } else {
    digitalWrite(BUZZER_PIN, LOW);
    Serial.println("Command failed; buzzer forced off");
  }
  delay(2000);
}

Test

Change the command from 0 to 1 and back. Confirm both the physical output and reported status. Swap the output levels if your module is active-low.

Continue with Intermediate: Automatic Night Light.