How To Make ESP32 PLC (Programmable Logic Controller)

[Sekhohub.online]

You’ll learn how to build your own DIY ESP32-based PLC using solid-state relays (SSR) for fast, silent, and durable switching—ideal for automation, home control, and smart industry.

Materials for the Project

1. 10 × PC817 Optocoupler
2. 10 × MOC3021 Optocoupler
3. 10 × BT136 TRIAC
4. 10x Red LED
5. 10x Yellow LED
6. 1x 1000uF 50V Capacitor
7. 20 × 100Ω Resistor
8. 10 × 220Ω Resistors
9. 10 × 1 kΩ Resistors
10. 12x 2-Pin Terminal Blocks
11. Jumper Wires

⚙️How to Program:

You can program the ESP32 in two ways:

Option 1: Arduino IDE (Manual Control Logic)

Use digitalWrite() to turn loads ON/OFF based on sensors, timers, etc.

#define RELAY_PIN 23

void setup() {
pinMode(RELAY_PIN, OUTPUT);
}

void loop() {
digitalWrite(RELAY_PIN, HIGH); // Turn ON load
delay(1000);
digitalWrite(RELAY_PIN, LOW); // Turn OFF load
delay(1000);
}

Option 2: OpenPLC for Ladder Programming

Install OpenPLC Editor on your PC
Write ladder logic (NO/NC contacts, coils)
Compile for ESP32 using OpenPLC firmware
Upload via USB or WiFi

✅Advantages of ESP32 PLC with SSR:

Silent operation (no clicks like mechanical relays)
High-speed switching
Durable (no moving parts)
Compact & reliable
WiFi and Bluetooth support
Suitable for industrial-grade projects

Applications:

Smart home automation
Industrial process control
IoT systems
Timed irrigation or motor control
Energy-efficient automation systems