![]() You can read more about the supported frequencies here. I will use 2000 Hz, but you can test with other frequencies, as long as they are supported. ![]() We will also declare these configuration parameters as global variables.įirst, we need specify the frequency, which will influence how the sound produced by the buzzer will be. ![]() Later, we will need to set some configurations regarding the waveform produced by the PWM hardware. To get started, we will first declare two variables to hold the number of the ESP32 pins connected to both the PIR motion sensor and the buzzer. Regarding the connection of the ESP32 to the buzzer, we will also only need to connect a digital pin of the microcontroller, which will produce the square wave needed to make the buzzer emit a sound. Note that although our circuit is operating at 3.3 V, a value of 3.0 V is still interpreted as a HIGH logical level by the ESP32, which means we can interact with the sensor considering it outputs a digital signal. Since we are already interacting with two modules, my recommendation is to use an external power supply such as this to supply the whole circuit.Īs can be seen in figure 1, one of the ESP32 GPIOs will be connected to the PIR sensor, since this device outputs a voltage of 3.0 V when motion is detected. Note that all the devices should have a common GND.Īlthough some ESP32 boards have a power supply pin to connect to other devices, many times the maximum current drawn that those pins can supply is not specified. The schematic for this is illustrated below in figure 1.īoth the buzzer and the PIR motion sensor can operate at 3.3 V, which facilitates the design of the circuit. The schematic for this tutorial is very simple, as we will only need to connect a pin of the ESP32 to the buzzer and another to the PIR motion sensor. The tests were performed using a DFRobot’s ESP32 module integrated in a ESP32 development board. I’m also assuming the use of a ready to use buzzer module, which can be directly controlled from a digital pin of a microcontroller. In this tutorial we will use a DFRobot’s PIR sensor module, which already contains all the electronics we need to connect the sensor to a microcontroller and start using it. As explained in that post, at the time of writing, the higher level Arduino tone function is not yet implemented in the ESP32 Arduino core, so we will leverage the LED PWM functionalities of this microcontroller to control the buzzer. To achieve this, we will need to use some FreeRTOS functions, as we will see below in the code sections.įor a tutorial on how to control a buzzer with the ESP32, please check here. We will leverage interrupts to avoid constantly polling the motion sensor, like we covered in this previous post. When the sensor stops detecting motion, then we stop the buzzer. We will be using the Arduino core, running on the ESP32.īasically, when motion is detected by the PIR sensor, we will trigger the buzzer to start emitting a loud sound. In this tutorial we will check how to create a very simple alarm system with a buzzer and a PIR motion sensor. We will be using the Arduino core, running on the ESP32. The tests were performed using a DFRobot’s ESP32 module integrated in a ESP32 development board, and a DFRobot’s PIR sensor module. ![]() ![]()
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