Matrix - Temperature and Humidity Sensor

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1 Introduction

Temperature and Humidity Sensor

This module utilizes the DHT11 temperature and humidity sensor. The DHT11 sensor's relative humidity range is 20%-80% ±5% and its temperature range is 0℃-50℃ ±2℃.DHT11的DATA线用于微处理器与 DHT11之间的通讯和同步,采用单总线数据格式, 仅仅需要一个 I/O 口，一次通讯时间4ms左右,数据分小数部分和整数部分，数据采用校验和方式进行校验。它应用专用的数字模块采集技术和温湿度传感技术，超小的体积、极低的功耗，信号传输距离可达20米以上。适合要求不高的场合使用。我们把DHT11的4针引脚简化为3针引出，并在PCB上加上固定孔，方便您安装使用。

Relative humidity Resolution: 16Bit Repeatability: ±1% RH Accuracy: At 25℃ ±5% RH Interchangeability: fully interchangeable Response time: 1 / e (63%) of 25℃ 6s 1m / s air 6s Hysteresis: <± 0.3% RH Long-term stability: <± 0.5% RH / yr in Temperature Resolution: 16Bit Repeatability: ±0.2℃ Range: At 25℃ ±2℃ Response time: 1 / e (63%) 10S Electrical Characteristics Power supply: DC 3.5～5.5V Supply Current: measurement 0.3mA standby 60μ A Sampling period: more than 2 seconds Pin Description 1, the VDD power supply 3.5～5.5V DC 2 DATA serial data, a single bus 3, NC, empty pin 4, GND ground, the negative powe

2 特性

• 测量范围 湿度20-80%RH， 温度0~50℃
• 测量精度 湿度+-5%RH， 温度+-2℃
• 一线协议
• 2.54mm排针接口，接线方便，通用性强

3 使用方法

3.1 连接

• 连接到Tiny4412 SDK (1506)

GND针脚: 接地

VCC: 接5V

S针脚：接GPIO PIN1, 必须使用中断引脚，可用引脚(1、2、3、4、9、10)

3.2 Linux下的C示例

#include <stdio.h>
#include <stdlib.h>
#include "libfahw.h"
 
void parseCmd(int argc, char **argv, int *pin)
{
    int num = atoi(argv[1]);
    switch(num) {
    case 1:
        *pin = TINY4412_GPIO_PIN1;
        break;
    case 2:
        *pin = TINY4412_GPIO_PIN2;
        break;
    case 3:
        *pin = TINY4412_GPIO_PIN3;
        break;
    case 4:
        *pin = TINY4412_GPIO_PIN4;
        break;
    case 9:
        *pin = TINY4412_GPIO_PIN9;
        break;
    case 10:
        *pin = TINY4412_GPIO_PIN10;
        break;
    default:
        printf("Unsupported pin TINY4412_GPIO_PIN%d\n", num);
        num = 1;
        *pin = TINY4412_GPIO_PIN1;
    }
    printf("Using pin TINY4412_GPIO_PIN%d\n", num);
}
 
int main(int argc, char ** argv)
{
    int ret = -1;
    int dhtTemp = 0;
    int dhtHdty = 0;
    int devFD = -1;
    int pin = TINY4412_GPIO_PIN1;
 
    if (argc == 2) {
        parseCmd(argc, argv, &pin);
    } else {
        printf("Using default pin TINY4412_GPIO_PIN1\n");
    }
    if ((devFD = dht11Init(pin)) == -1) {
        printf("Fail to init dht11\n");
        return -1;
    }
 
    if ((ret = dht11Read(DHT_HUMIDITY, &dhtHdty)) != -1) {
        printf("Get humidity : %d\n", dhtHdty);
    } else {
        printf("Faided to get humidity\n");
    }
 
    if ((ret = dht11Read(DHT_TEMP, &dhtTemp)) != -1) {
        printf("Get temperature : %d\n", dhtTemp);
    } else {
        printf("Faided to get temperature\n");
    }
 
    dht11DeInit(devFD);
    return ret;
}

3.3 编译并运行示例

git clone http://github.com/friendlyarm/fa-hardware.git
cd fa-hardware
cd demo
cd matrix-temperature_and_humidity_sensor
make

将编译生成的dht11通过ftp上传到开发板上运行即可测试。