Nodejs 各位大神,谁能帮我把这段代码写成nodejs版的啊,谢谢啦
Nodejs 各位大神,谁能帮我把这段代码写成nodejs版的啊,谢谢啦
/*
- dht11.c:
- Simple test program to test the wiringPi functions
- DHT11 test
*/
#include <wiringPi.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#define MAXTIMINGS 85
#define DHTPIN 7
int dht11_dat[5] = {0,0,0,0,0};
void read_dht11_dat()
{
uint8_t laststate = HIGH;
uint8_t counter = 0;
uint8_t j = 0, i;
float f; // fahrenheit
dht11_dat[0] = dht11_dat[1] = dht11_dat[2] = dht11_dat[3] = dht11_dat[4] = 0;
// pull pin down for 18 milliseconds
pinMode(DHTPIN, OUTPUT);
digitalWrite(DHTPIN, LOW);
delay(18);
// then pull it up for 40 microseconds
digitalWrite(DHTPIN, HIGH);
delayMicroseconds(40);
// prepare to read the pin
pinMode(DHTPIN, INPUT);
// detect change and read data
for ( i=0; i< MAXTIMINGS; i++) {
counter = 0;
while (digitalRead(DHTPIN) == laststate) {
counter++;
delayMicroseconds(1);
if (counter == 255) {
break;
}
}
laststate = digitalRead(DHTPIN);
if (counter == 255) break;
// ignore first 3 transitions
if ((i >= 4) && (i%2 == 0)) {
// shove each bit into the storage bytes
dht11_dat[j/8] <<= 1;
if (counter > 16)
dht11_dat[j/8] |= 1;
j++;
}
}
// check we read 40 bits (8bit x 5 ) + verify checksum in the last byte
// print it out if data is good
if ((j >= 40) &&
(dht11_dat[4] == ((dht11_dat[0] + dht11_dat[1] + dht11_dat[2] + dht11_dat[3]) & 0xFF)) ) {
f = dht11_dat[2] * 9. / 5. + 32;
printf(“Humidity = %d.%d %% Temperature = %d.%d *C (%.1f *F)\n”,
dht11_dat[0], dht11_dat[1], dht11_dat[2], dht11_dat[3], f);
}
else
{
printf(“Data not good, skip\n”);
}
}
int main (void)
{
printf (“Raspberry Pi wiringPi DHT11 Temperature test program\n”) ;
if (wiringPiSetup () == -1)
exit (1) ;
while (1)
{
read_dht11_dat();
delay(1000); // wait 1sec to refresh
}
return 0 ;
}
好的,下面是将 C 语言代码转换为 Node.js 版本的示例。我们将使用 onoff
和 gpiod
模块来读取 GPIO 引脚的数据。
示例代码
首先,确保你已经安装了必要的依赖项:
npm install onoff gpiod
然后,你可以创建一个名为 dht11.js
的文件,并添加以下代码:
const Gpio = require('gpiod');
const { Readable } = require('stream');
class DHT11 extends Readable {
constructor(chip, line) {
super({ objectMode: true });
this.chip = new Gpio.Chip(chip);
this.line = this.chip.getLine(line);
this.line.request({ direction: Gpio.DIRECTION.INPUT, consumer: 'DHT11' });
}
async read() {
const data = [0, 0, 0, 0, 0];
const maxTimings = 85;
let lastState = 1;
let counter = 0;
let j = 0;
// Pull pin down for 18 milliseconds
this.line.setValue(0);
await this.sleep(18);
// Then pull it up for 40 microseconds
this.line.setValue(1);
await this.sleep(40);
// Prepare to read the pin
this.line.setValue(1);
this.line.setInputConfig(Gpio.INPUT_CONFIG_PULL_UP);
// Detect change and read data
for (let i = 0; i < maxTimings; i++) {
counter = 0;
while (this.line.getValue() === lastState) {
counter++;
await this.sleep(1);
if (counter >= 255) {
break;
}
}
lastState = this.line.getValue();
if (counter >= 255) break;
// Ignore first 3 transitions
if (i >= 4 && i % 2 === 0) {
// Shove each bit into the storage bytes
data[j / 8] <<= 1;
if (counter > 16) {
data[j / 8] |= 1;
}
j++;
}
}
// Check we read 40 bits (8bit x 5) + verify checksum in the last byte
// Print it out if data is good
if (j >= 40 && data[4] === ((data[0] + data[1] + data[2] + data[3]) & 0xFF)) {
const temperatureC = data[2];
const temperatureF = temperatureC * 9 / 5 + 32;
console.log(`Humidity = ${data[0]}.${data[1]} % Temperature = ${temperatureC}.${data[3]} *C (${temperatureF.toFixed(1)} *F)`);
} else {
console.log('Data not good, skip');
}
}
sleep(ms) {
return new Promise(resolve => setTimeout(resolve, ms));
}
_read() {
this.read();
}
}
const dht11 = new DHT11('gpiochip0', 7);
setInterval(() => {
dht11.read();
}, 1000);
解释
-
初始化:
- 使用
gpiod
模块请求 GPIO 引脚。 - 创建一个
DHT11
类,继承自Readable
流,以便我们可以轻松地读取数据。
- 使用
-
读取数据:
- 通过设置 GPIO 引脚的值来触发 DHT11 传感器。
- 读取引脚状态并解析数据。
- 验证数据的有效性,并计算湿度和温度。
-
循环读取:
- 使用
setInterval
每秒调用一次read
方法以获取新的数据。
- 使用
这样,你就有了一个基于 Node.js 的 DHT11 温湿度传感器读取程序。
外包?
可以参考,帮忙写就太为难了。。 http://blog.whattoc.com/2013/09/08/nodejs_api_addon_4/
当然可以!以下是将上述 C 语言代码转换为 Node.js 版本的示例。这里我们使用 onoff
和 bcdirect-io
这两个库来读取 GPIO 引脚的状态。
首先,安装必要的依赖库:
npm install onoff bcdirect-io
然后,使用以下代码实现 DHT11 传感器的数据读取:
const Gpio = require('bcdirect-io');
const GpioSensor = require('onoff').Gpio;
const DHT_PIN = 7;
function readDht11Dat() {
const gpio = new Gpio(DHT_PIN, 'in', 'both');
let lastState = 1;
let counter = 0;
let j = 0;
const data = [0, 0, 0, 0, 0];
gpio.writeSync(0); // 拉低引脚18毫秒
setTimeout(() => {
gpio.writeSync(1); // 拉高引脚40微秒
setTimeout(() => {
gpio.watch((err, value) => {
if (value !== lastState) {
counter++;
if (counter > 255) {
return;
}
if ((j >= 4) && (j % 2 === 0)) {
data[Math.floor(j / 8)] <<= 1;
if (counter > 16) {
data[Math.floor(j / 8)] |= 1;
}
j++;
}
lastState = value;
}
});
}, 40);
}, 18);
setTimeout(() => {
gpio.unexport();
}, 85 * 1000);
setTimeout(() => {
if (j >= 40 && data[4] === ((data[0] + data[1] + data[2] + data[3]) & 0xFF)) {
const temperatureCelsius = data[2];
const temperatureFahrenheit = temperatureCelsius * 9 / 5 + 32;
console.log(`Humidity = ${data[0]}.${data[1]}% Temperature = ${temperatureCelsius}.${data[3]}°C (${temperatureFahrenheit.toFixed(1)}°F)`);
} else {
console.log('Data not good, skip');
}
}, 85 * 1000);
}
setInterval(readDht11Dat, 1000);
这段代码实现了从 DHT11 传感器读取温度和湿度数据,并打印到控制台。每隔一秒执行一次读取操作。