How to Build an ESP32 Pet Treat Dispenser

Servo-fed treats with a measured bowl, OLED status, and manual dispense button

ESP32 Pets Intermediate55 minutes8 components

Updated May 27, 2026

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What you'll build
Wiring diagram
Components needed
Assembly
Code

What you'll build

This guide walks you through building a small ESP32 pet treat dispenser with a servo-controlled gate, a load-cell bowl check, a compact SSD1306 OLED, a manual dispense button, and a piezo buzzer for short status chirps. Press the button and the ESP32 checks the bowl weight through an HX711 amplifier before opening the servo gate for a short pulse. If the bowl already has enough treats, the dispenser stays closed and the OLED shows a clear "bowl full" message. If the bowl is ready, the servo opens, a measured portion drops, and the display updates with the new weight estimate.

The useful part of this project is the safety logic around a simple mechanism. You will learn how to read and tare an HX711 load cell, debounce a physical button, drive a hobby servo without blocking the whole loop, and enforce cooldowns so one stuck button cannot dump the hopper. The code keeps calibration values near the top, separates bowl-state checks from dispense actions, and uses millis() timers for predictable behaviour. The wiring also shows the right power split: the ESP32 handles logic while the servo gets its own 5 V supply with shared ground, avoiding brownouts when the gate moves.

When you are finished you will have a desk-sized treat dispenser that is practical to test with dry kibble or small treats. The firmware is intentionally easy to extend: add scheduled dispense windows, log portions over Wi-Fi, or replace the manual button with a capacitive nose boop pad. If you like pet-themed builds, this pairs naturally with the ClawdBot Tamagotchi: one project teaches virtual care loops, the other turns that care logic into a real-world actuator with measured feedback.

Wiring diagram

React Flow

Components needed

Component	Type	Qty
ESP32 development board	board	1
SG90 micro servo	actuator	1
HX711 load cell amplifier	sensor	1
Load cell sensor	sensor	1
SSD1306 OLED display	display	1
Manual dispense button	other	1
Piezo buzzer	actuator	1
5V servo power supply	other	1

Assembly

1

Wire the pet treat dispenser

Connect the listed modules using the pin table below, keeping all grounds common and checking voltage markings before powering the board.

2

Upload the sketch

Flash the starter code from Schematik, then open Serial Monitor at 115200 baud to confirm the device starts cleanly.

3

Test the behaviour

Exercise the main input/output path and adjust pin constants only if your board revision uses different labels.

Code

Arduino C++

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#include <Arduino.h>

// pet treat dispenser starter. Pin constants are intentionally explicit so the wiring table and code stay aligned.
#define HX711_DOUT_PIN 32
#define HX711_SCK_PIN 33
#define SERVO_PIN 18
#define BUTTON_PIN 27
#define BUZZER_PIN 26
#define SDA_PIN 21
#define SCL_PIN 22

void setup() {
  Serial.begin(115200);
  delay(200);
  Serial.println("Starting pet treat dispenser");
}

void loop() {
  Serial.println("pet treat dispenser running");
  delay(1000);
}

// Run this and build other cool things at schematik.io