Monitoring Current with ESP32 and ACS712 Sensor

Current Sensor with ESP32 and Blink

Materials Needed

• ACS712 current sensor
• ESP32 microcontroller
• Socket and plug for load connection
• Jumper wires

Setup

1. Place the ESP32 on a carrier board.
2. Connect three jumper wires to the current sensor:
• VCC of the current sensor to 3.3V pin of ESP32
• Ground of the current sensor to ground of ESP32
• Output pin of the current sensor to GPIO34 pin of ESP32

Connecting the Load

Setting up Blink

1. Create a template in the Blink dashboard.
2. Create a virtual pin data stream.
3. Create a web dashboard.

Creating a Device

Setting up the Mobile Dashboard

Coding

1. Copy the code from the GitHub repository.
2. Open Arduino IDE and paste the code.

Code Explanation

const char* BLINK_TEMPLATE_ID = "your_template_id";
const char* BLINK_TEMPLATE_NAME = "your_template_name";
const char* BLINK_AUTH_TOKEN = "your_auth_token";

#include <ACS712.h>
#include <WiFi.h>

// Initialize ACS712 object
ACS712 sensor(34, 3.3, 4095, 125);

void setup() {
  // Connect to WiFi
  WiFi.begin(ssid, password);
}

void loop() {
  // Read current value from sensor
  int currentValue = readCurrent();

  // Send current value to Blink virtual pin V0
  blink.send(V0, currentValue);
}

Calibration

1. Upload the code to the ESP32.
2. Open the serial monitor and read the no-load current value.
3. Assign this value to the calibration factor in the code.
4. Re-upload the code.

Testing

1. Connect a load to the current sensor.
2. Read the current value from the sensor using the code.
3. Verify that the current value is correct.

Introduction

What is the ACS712 Sensor?

Hardware Requirements

• ESP32 development board (e.g. ESP32 DevKitC)
• ACS712 current sensor module
• Breadboard and jumper wires
• DC power source (e.g. battery or wall adapter)

Circuit Connection

Connect the ACS712 sensor module to the ESP32 development board as follows:

• VCC pin of the ACS712 to the VIN pin of the ESP32
• GND pin of the ACS712 to the GND pin of the ESP32
• OUT pin of the ACS712 to any analog input pin of the ESP32 (e.g. A0)

Software Requirements

You will need to install the following libraries:

• ESP32 Arduino Core (if you are using the Arduino IDE)
• ACS712 library (available on GitHub)

Code Example

Here is an example code that reads the current value from the ACS712 sensor and prints it to the serial monitor:

#include <ACS712.h>

const int ACS712_PIN = A0;
ACS712 acs(ACS712_PIN);

void setup() {
  Serial.begin(115200);
}

void loop() {
  float current = acs.getCurrent();
  Serial.print("Current: ");
  Serial.println(current, 2);
  delay(1000);
}

How it Works

Conclusion

• Microcontroller: Tensilica Xtensa LX6
• Clock Speed: Up to 240 MHz
• Memory: 520 KB SRAM, 4 MB Flash
• Communication Protocols: Wi-Fi, Bluetooth, UART, SPI, I2C

• Sensing Range: ±5A, ±20A, or ±30A depending on the model
• Sensitivity: 185 mV/A (±5A), 100 mV/A (±20A), or 66 mV/A (±30A)
• Accuracy: ±1.5% at room temperature
• Operating Temperature: -40°C to +85°C

• Resolution: 12-bit (4096 steps)
• Sampling Rate: Up to 200 ksps
• Input Range: 0-3.3V

const int ACS712_PIN = 34; // Pin connected to the ACS712 sensor

void setup() {
  Serial.begin(115200);
  pinMode(ACS712_PIN, INPUT);
}

void loop() {
  int adcValue = analogRead(ACS712_PIN);
  float current = mapFloat(adcValue, 0, 4095, -30, 30); // Map the ADC value to a current value
  Serial.println(current);
  delay(1000);
}