Grove- Temperature and Humidity Sensor

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RB-See-188

Seeedstudio Grove Temperature / Humidity Sensor

Introduction

This temperature & humidity sensor provides a pre-calibrated digital output. A unique capacitive sensor

element measures relative humidity and the temperature is measured by a negative temperature

coefficient (NTC) thermistor. It has excellent reliability and long term stability. Please note that this

sensor will not work for temperatures below 0 degree.

Features

 Relative Humidity and temperature measurement

 Full range temperature compensation Calibrated

 Digital signal

 Long term stability

 Long transmission distance(>20m)

 Low power consumption

Summary of content (9 pages)

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RB-See-188 Seeedstudio Grove Temperature / Humidity Sensor Grove- Temperature and Humidity Sensor Introduction This temperature & humidity sensor provides a pre-calibrated digital output. A unique capacitive sensor element measures relative humidity and the temperature is measured by a negative temperature coefficient (NTC) thermistor. It has excellent reliability and long term stability. Please note that this sensor will not work for temperatures below 0 degree.
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Applications Ideas     Consumption product Weather station Humidity regulator Air conditioner Schematic Specifications Key Specification Items Min PCB Size 2.0cm*4.0cm Interface 2.
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IO Structure SIG,VCC,GND,NC ROHS YES Electronic Characterstics Items Conditions Min Norm Max Unit VCC - 3.3 - 5 Volts Measuring Current Supply - 1.3 - 2.1 mA Average Current Supply - 0.5 - 1.
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Temperature Long-term Stability Signal Collecting Period 2 ±1 °C ±1% RH/year S Usage When MCU sends a trigger signal, sensor will change from low power consumption mode to active mode. After the trigger signal sensor will send a response signal back to MCU, then 40 bit collected data is sent out and a new signal collecting is trigged.(Note that the 40 bit collected data which is sent from sensor to MCU is already collected before the trigger signal comes.
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Programming Connect the Temperature and Humidity sensor to analog port A0.Then you can use the following programme to gain the temperature and humidity of the environment.(The code is for seeeduino only,if you use seeeduino mega you should change the code a little.
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while(!(PINC & _BV(DHT11_PIN))); // wait for 50us delayMicroseconds(30); if(PINC & _BV(DHT11_PIN)) result |=(1<<(7-i)); while((PINC & _BV(DHT11_PIN))); // wait '1' finish } return result; } void setup() { DDRC |= _BV(DHT11_PIN); PORTC |= _BV(DHT11_PIN); Serial.begin(9600); Serial.
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byte dht11_dat[5]; byte dht11_in; byte i; // start condition // 1. pull-down i/o pin from 18ms PORTC &= ~_BV(DHT11_PIN); delay(18); PORTC |= _BV(DHT11_PIN); delayMicroseconds(40); DDRC &= ~_BV(DHT11_PIN); delayMicroseconds(40); dht11_in = PINC & _BV(DHT11_PIN); if(dht11_in){ Serial.println("dht11 start condition 1 not met"); return; } delayMicroseconds(80); dht11_in = PINC & _BV(DHT11_PIN); if(!dht11_in){ Serial.
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return; } delayMicroseconds(80); // now ready for data reception for (i=0; i<5; i++) dht11_dat[i] = read_dht11_dat(); DDRC |= _BV(DHT11_PIN); PORTC |= _BV(DHT11_PIN); byte dht11_check_sum = dht11_dat[0]+dht11_dat[1]+dht11_dat[2]+dht11_dat[3]; // check check_sum if(dht11_dat[4]!= dht11_check_sum) { Serial.println("DHT11 checksum error"); } Serial.print("Current humdity = "); Serial.print(dht11_dat[0], DEC); Serial.print("."); Serial.print(dht11_dat[1], DEC); Serial.print("% "); Serial.
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Serial.print(dht11_dat[3], DEC); Serial.