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ACS712 – Current Sensor

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Overview

Electronic brick of current sensor is based on ACS712 sensor, which can accurately detect AC or DC signals. The maximum AC or DC that can be detected can reach 5A, and the present current signal can be read via analog I / O port.

Features

1. Plug and play, easy to use. Compatible with the mainstream 2.54 interfaces and 4-Pin Grove interfaces in the market.

2. With use of M4 standard fixed holes, compatible with M4-standard kits such as Lego and Makeblock.

3. Terminals with screws for easy wiring and removing.

Specifications

PCB size 30.0mm X 24.0mm X 1.6mm
Working voltage 5V
Input current type AC or DC
Compatible interfaces 2.54 3-pin interface and 4-pin Grove interface(1)
Wiring interface Power terminal(2)

Note 1： S for analog output port, V and G for voltage at the common collector and ground respectively

Note 2: “+”for current inflow port“-”for current outflow port

Electrical characteristics

Parameter Min.     Typical     Max.     Unit
Supply voltage 4.5 5 5.5 VDC
Working current（VCC=5V） – 10 13 mA
Output impedance RLOAD（VIOUT to GND） 4.7 – – KΩ
Bandwidth(1) – 34 – Hz
Input current range -5 – 5 A
Sensitivity 180 185 190 mV/A

Note 1： After removing C1, bandwidth can reach 80kHz

Relationship between output voltage and induced current

DEMO

Connect S port of electronic brick of current sensor to A0 port of Arduino board, and we will use the following program to read the analog value and send it to the computer for display via serial port.

#define CURRENT_SENSOR A0 // Analog input pin that sensor is attached to

float amplitude_current;               //amplitude current
float effective_value;       //effective current 

void setup() 
{
    Serial.begin(9600); 
    pins_init();
}
void loop() 
{
    int sensor_max;
    sensor_max = getMaxValue();
    Serial.print("sensor_max = ");
    Serial.println(sensor_max);
    //the VCC on the Grove interface of the sensor is 5v
    amplitude_current=(float)(sensor_max-512)/1024*5/185*1000000;
    effective_value=amplitude_current/1.414;
    //minimum_current=1/1024*5/185*1000000/1.414=18.7(mA)
    //Only for sinusoidal alternating current
    Serial.println("The amplitude of the current is(in mA)");
    Serial.println(amplitude_current,1);//Only one number after the decimal point
    Serial.println("The effective value of the current is(in mA)");
    Serial.println(effective_value,1);
}
void pins_init()
{
    pinMode(CURRENT_SENSOR, INPUT);
}
/*Function: Sample for 1000ms and get the maximum value from the S pin*/
int getMaxValue()
{
    int sensorValue;             //value read from the sensor
    int sensorMax = 0;
    uint32_t start_time = millis();
    while((millis()-start_time) < 1000)//sample for 1000ms
    {
        sensorValue = analogRead(CURRENT_SENSOR);
        if (sensorValue > sensorMax) 
        {
            /*record the maximum sensor value*/
            sensorMax = sensorValue;
        }
    }
    return sensorMax;
}

 

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