Creating your own current sensor using the ESP32 can be an exciting project that blends electronics and programming. The ESP32 is a powerful microcontroller with built-in Wi-Fi and Bluetooth capabilities, making it ideal for IoT applications. In this article, we will explore how to build a DIY current sensor using the ESP32.
What You Need
Components
- ESP32 Development Board: This will serve as the brain of your project.
- Current Sensor Module: Common options include the ACS712 or the INA219.
- Breadboard and Jumper Wires: For prototyping and connections.
- Power Supply: Depending on your current sensor module, you will need a suitable power supply.
- Resistors: Depending on your design, you may require resistors for voltage division.
- Optional: An OLED display to visualize the readings.
Tools
- Soldering iron (if you choose to make a permanent version)
- Multimeter (for testing)
- Computer with Arduino IDE or ESP-IDF installed
Step-by-Step Guide
1. Wiring the Circuit
Connect the ESP32 to your current sensor according to the datasheet provided with the module. For example, if you're using the ACS712, you would typically connect:
- VCC to 5V (or the appropriate power supply)
- GND to Ground
- OUT to one of the analog input pins on the ESP32, such as GPIO 34.
2. Setting Up the Arduino IDE
-
Install the ESP32 Board Manager:
- Open Arduino IDE.
- Go to File > Preferences and add the ESP32 board URL to the "Additional Boards Manager URLs".
- Open the Boards Manager and install the ESP32 package.
-
Select Your Board:
- Go to Tools > Board and select your ESP32 model.
3. Coding the ESP32
Here’s a simple code snippet to read the current sensor data. This example uses the ACS712:
#include <Arduino.h>
const int currentPin = 34; // Set the pin where the sensor is connected
float sensorValue;
void setup() {
Serial.begin(115200);
}
void loop() {
sensorValue = analogRead(currentPin); // Read the analog input
// Convert the analog value to current in Amperes
float voltage = (sensorValue / 4095.0) * 3.3; // 3.3V is the reference voltage
float current = (voltage - 2.5) / 0.185; // Adjust for your sensor's sensitivity (for ACS712 5A)
Serial.print("Current: ");
Serial.print(current);
Serial.println(" A");
delay(1000); // Wait for 1 second
}
4. Uploading the Code
Connect your ESP32 to your computer via USB and upload the code. Open the Serial Monitor to view the current readings.
5. Calibrating Your Sensor
It's essential to calibrate your sensor to ensure accurate readings. You can compare the output with a known reference and adjust the formula accordingly in the code.
Optional Enhancements
Adding an OLED Display
To visualize the current readings, you can connect an OLED display (like the SSD1306) to your ESP32. You’ll need the corresponding libraries, and the code can be modified to display values on the screen.
IoT Integration
Consider pushing your readings to a cloud service or creating a web interface to monitor the current remotely using ESP32’s Wi-Fi capabilities. Libraries like HTTPClient can be used for this purpose.
Conclusion
Building a DIY current sensor with the ESP32 is an engaging way to explore electronics and programming. By following the steps outlined above, you can create a functional current monitoring system. With further enhancements, you can expand your project into a full-fledged IoT application. Happy tinkering!
