ESP8266 - Siren

This tutorial instructs you on how to program ESP8266 to control a siren to produce a warning sound and/or light.

Hardware Preparation

1	×	ESP8266 NodeMCU
1	×	Micro USB Cable
1	×	Relay
1	×	12V Alarm Siren Horn
1	×	12V Power Adapter
1	×	DC Power Jack
1	×	Jumper Wires
1	×	Breadboard
1	×	(Optional) Screw Terminal Expansion Board for ESP8266

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables.

Overview of Siren

Depending on the manufacturer, a siren can produce either a loud sound or a warning light, making it suitable for an alarm system. It is also available in several operating voltages. This tutorial will use a 12V siren, and other voltages will be similar.

Pinout

12V siren usually has two pins:

Negative (-) pin (black): needs to be connected to GND of DC power supply
Positive (+) pin (red): needs to be connected to 12V of DC power supply

How to Control a Siren

If 12V siren is powered by 12V power supply, it make sound and/or warning light. To control a 12V siren, we need to use a relay in between ESP8266 and 12V siren. ESP8266 can control the 12V siren via the relay. If you do not know about relay (pinout, how it works, how to program ...), learn about relay in the ESP8266 - Relay tutorial

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

See more in ESP8266's pinout and how to supply power to the ESP8266 and other components.

ESP8266 Code

The below code repeatedly turns the 12V siren ON in two seconds and OFF in four seconds,

/* * This ESP8266 NodeMCU code was developed by newbiely.com * * This ESP8266 NodeMCU code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/esp8266/esp8266-siren */ #define RELAY_PIN D7 // The ESP8266 pin that controls the siren via relay // The setup function runs once on reset or power-up void setup() { // initialize digital pin D4 as an output. pinMode(RELAY_PIN, OUTPUT); } // The loop function repeats indefinitely void loop() { digitalWrite(RELAY_PIN, HIGH); // turn on siren 2 seconds delay(2000); digitalWrite(RELAY_PIN, LOW); // turn off siren 5 seconds delay(4000); }

Detailed Instructions

To get started with ESP8266 on Arduino IDE, follow these steps:

Check out the how to setup environment for ESP8266 on Arduino IDE tutorial if this is your first time using ESP8266.
Wire the components as shown in the diagram.
Connect the ESP8266 board to your computer using a USB cable.
Open Arduino IDE on your computer.
Choose the correct ESP8266 board, such as (e.g. NodeMCU 1.0 (ESP-12E Module)), and its respective COM port.
Connect ESP8266 to PC via USB cable
Open Arduino IDE, select the right board and port
Copy the above code and open with Arduino IDE
Click Upload button on Arduino IDE to upload code to ESP8266
Check out the siren's state

Code Explanation

Read the line-by-line explanation in comment lines of code!

Video Tutorial

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