# Grove Electricity Sensor ![](https://raw.githubusercontent.com/SeeedDocument/Grove-Electricity_Sensor/master/img/Twig-Electricity-Sensor.jpg) The Electricity sensor module is a member of Grove. It is based on the TA12-200 current transformer which can transform the large AC into small amplitude. You can use it to test large alternating current up to 5A. [![](https://raw.githubusercontent.com/SeeedDocument/common/master/Get_One_Now_Banner.png)](http://www.seeedstudio.com/Grove-Electricity-Sensor-p-777.html) ## Features * Grove compatible interface * Maximum 5A input * High accuracy * Small size !!!Tip More details about Grove modules please refer to [Grove System](http://wiki.seeed.cc/Grove_System/) ## Application Ideas * Alternating current measurement * Device condition monitoring ## Specification ### Key Specification | **Items** | **Min** | | ------------ | ---------------------- | | PCB Size | 2.0cm\*4.0cm | | Interface | 2.0mm pitch pin header | | IO Structure | SIG,NC,NC,GND | | RoHS | YES | ### Electronic Characteristics | **Items** | **Min** | **Norm** | **Max** | **Unit** | | --------------------- | ------- | -------- | ------- | --------- | | Transformation ratio | - | 2000:1 | - | - | | Input Current | 0 | - | 5 | A | | Output Current | 0 | - | 2.5 | mA | | Sampling Resistance | - | 800 | - | Ω | | Sampling Voltage | 0 | - | 2 | V | | Working Frequency | 20 | - | 20K | HZ | | Nonlinear scale | - | - | 0.2% | - | | Phase Shift | - | - | 5' | - | | Operating Temperature | -55 | - | 85 | ℃ | | Dielectric strength | - | 6 | - | KVAC/1min | ## Platforms Supported ## Usage ### With [Arduino](https://app.gitbook.com/Arduino) The following sketch demonstrates a simple application of measuring the amplitude of the alternating voltage. The SIG pin will output a alternating voltage based on the alternating current being measured. You can measure the value using ADC. * Connect the module to the analog A0 of [Grove - Base board](http://www.seeedstudio.com/depot/grove-base-shield-p-754.html?cPath=132_134). * Put the alternating current wire through the hole of the current transformer. ![](https://raw.githubusercontent.com/SeeedDocument/Grove-Electricity_Sensor/master/img/Grove-Electricity_Sensor_hardware.jpg) * Copy and paste code below to a new Arduino sketch. ``` /****************************************************************************/ // Function: Measure the amplitude current of the alternating current and // the effective current of the sinusoidal alternating current. // Hardware: Grove - Electricity Sensor // Date: Jan 19,2013 // by www.seeedstudio.com #define ELECTRICITY_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/1024*5/800*2000000; effective_value=amplitude_current/1.414;//minimum_current=1/1024*5/800*2000000/1.414=8.6(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(ELECTRICITY_SENSOR, INPUT); } /*Function: Sample for 1000ms and get the maximum value from the SIG 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(ELECTRICITY_SENSOR); if (sensorValue > sensorMax) { /*record the maximum sensor value*/ sensorMax = sensorValue; } } return sensorMax; } ``` * Upload the code. Note The minimum effective current that can be sensed by the code can be calculated using the equation below. minimum\_current=1/1024\*5/800\*2000000/1.414=8.6(mA). * Open the serial monitor, The results is as follows： ![](https://raw.githubusercontent.com/SeeedDocument/Grove-Electricity_Sensor/master/img/Elecricity_Sensor.jpg) ### With Raspberry Pi 1.You should have got a raspberry pi and a grovepi or grovepi+. 2.You should have completed configuring the development enviroment, otherwise follow [here](https://app.gitbook.com/GrovePiPlus). 3.Connection * Plug the sensor to grovepi socket A0 by using a grove cable. 4.Navigate to the demos' directory: ``` cd yourpath/GrovePi/Software/Python/ ``` * To see the code ``` nano grove_electricity_sensor.py # "Ctrl+x" to exit # ``` ``` import time import grovepi # Connect the Grove Electricity Sensor to analog port A0 # SIG,NC,NC,GND sensor = 0 grovepi.pinMode(sensor,"INPUT") # Vcc of the grove interface is normally 5v grove_vcc = 5 while True: try: # Get sensor value sensor_value = grovepi.analogRead(sensor) # Calculate amplitude current (mA) amplitude_current = (float)(sensor_value / 1024 * grove_vcc / 800 * 2000000) # Calculate effective value (mA) effective_value = amplitude_current / 1.414 # minimum_current = 1 / 1024 * grove_vcc / 800 * 2000000 / 1.414 = 8.6(mA) # Only for sinusoidal alternating current print "sensor_value", sensor_value print "The amplitude of the current is", amplitude_current, "mA" print "The effective value of the current is", effective_value, "mA" time.sleep(1) except IOError: print "Error" ``` 5.Run the demo. ``` sudo python grove_electricity_sensor.py ``` ## Resources * [Grove -Electricity Sensor Eagle File](https://raw.githubusercontent.com/SeeedDocument/Grove-Electricity_Sensor/master/res/Electricity_sensor_v1.0_eagle_files.zip) * [Schematic in PDF](https://raw.githubusercontent.com/SeeedDocument/Grove-Electricity_Sensor/master/res/Electricity_sensor_sch.pdf)