Node.js 湿度和温度传感器插件_C语言_C++_JavaScript_代码_相关文件_下载

# node-dht-sensor A simple node.js module for reading temperature and relative humidity using a compatible DHT sensor.  [](https://www.npmjs.com/package/node-dht-sensor) [](https://www.npmjs.com/package/node-dht-sensor) [](https://github.com/momenso/node-dht-sensor/blob/master/LICENSE) ## Installation ```shell session $ npm install node-dht-sensor ``` Please note that differently from versions 0.0.x there's no need to pre-install the BCM2835 library [2]. ## Usage To initialize the sensor, you have to specify the sensor type and the [GPIO pin](https://www.raspberrypi.org/documentation/usage/gpio/) where the sensor is connected to. It should work for DHT11, DHT22 and AM2302 sensors. You should use sensorType value to match the sensor as follows: | Sensor | sensorType value | | --------------- | :--------------: | | DHT11 | 11 | | DHT22 or AM2302 | 22 | If the initialization succeeds when you can call the read function to obtain the latest readout from the sensor. Readout values contains a temperature and a humidity property. ### First Example  This sample queries a DHT11 sensor connected to the GPIO 4 and prints out the result on the console. ```javascript var sensor = require("node-dht-sensor"); sensor.read(11, 4, function(err, temperature, humidity) { if (!err) { console.log(`temp: ${temperature}°C, humidity: ${humidity}%`); } }); ``` ### Multiple Sensors Example  The following example shows a method for querying multiple sensors connected to the same Raspberry Pi. For this example, we have two sensors: 1. A DHT11 sensor connected to GPIO 17 2. High-resolution DHT22 sensor connected to GPIO 4 ```javascript var sensorLib = require("node-dht-sensor"); var app = { sensors: [ { name: "Indoor", type: 11, pin: 17 }, { name: "Outdoor", type: 22, pin: 4 } ], read: function() { for (var sensor in this.sensors) { var readout = sensorLib.read( this.sensors[sensor].type, this.sensors[sensor].pin ); console.log( `[${this.sensors[sensor].name}] ` + `temperature: ${readout.temperature.toFixed(1)}°C, ` + `humidity: ${readout.humidity.toFixed(1)}%` ); } setTimeout(function() { app.read(); }, 2000); } }; app.read(); ``` ### Promises API Promises API provides an alternative `read` method that returns a Promise object rather than using a callback. The API is accessible via `require('node-dht-sensor').promises`. ```javascript var sensor = require("node-dht-sensor").promises; // You can use `initialize` and `setMaxTries` just like before sensor.setMaxRetries(10); sensor.initialize(22, 17); // You can still use the synchronous version of `read`: // var readout = sensor.readSync(22, 4); sensor.read(22, 17).then( function(res) { console.log( `temp: ${res.temperature.toFixed(1)}°C, ` + `humidity: ${res.humidity.toFixed(1)}%` ); }, function(err) { console.error("Failed to read sensor data:", err); } ); ``` Using `async/await`: ```javascript const sensor = require("node-dht-sensor").promises; async function exec() { try { const res = await sensor.read(22, 4); console.log( `temp: ${res.temperature.toFixed(1)}°C, ` + `humidity: ${res.humidity.toFixed(1)}%` ); } catch (err) { console.error("Failed to read sensor data:", err); } } exec(); ``` ### Test mode A _test mode_ of operation is available since version `0.2.0`. In this mode of operation, the library does not communicate with the sensor hardware via the **GPIO** but instead it returns a pre-configured readout value. You can use the test mode during development without the need to have an actual sensor connected. To enable the _test mode_, fake values must be defined at initialization. In the example below we specify fixed values for temperature equal to 21°C and humidity equal to 60%. ```javascript sensor.initialize({ test: { fake: { temperature: 21, humidity: 60 } } }); ``` After initialization, we can call the `read` method as usual. ```javascript sensor.read(22, 4, function(err, temperature, humidity) { if (!err) { console.log( `temp: ${temperature.toFixed(1)}°C, ` + `humidity: ${humidity.toFixed(1)}%` ); } }); ``` And the result will always be the configured readout value defined at initialization. ```shell session $ node examples/fake-test.js temp: 21.0°C, humidity: 60.0% $ node examples/fake-test.js temp: 21.0°C, humidity: 60.0% ``` You can find a complete source code example in [examples/fake-test.js](https://github.com/momenso/node-dht-sensor/blob/master/examples/fake-test.js). ### Reference for building from source Standard node-gyp commands are used to build the module. So, just make sure you have node and node-gyp as well as the Broadcom library to build the project. 1. In case, you don't have node-gyp, install it first: ```shell session $ sudo npm install -g node-gyp $ sudo update-alternatives --install /usr/bin/node-gyp node-gyp /opt/node-v10.15.3-linux-armv7l/bin/node-gyp 1 ``` 2. Generate the configuration files ```shell session $ node-gyp configure ``` 3. Build the component ```shell session $ node-gyp build ``` ### Tracing and Debugging Verbose output from the module can be enabled by by specifying the `--dht_verbose=true` flag when installing the node via npm. ```shell session $ npm install node-dht-sensor --dht_verbose=true ``` if you are interested in enabling trace when building directly from source you can enable the `-Ddht_verbose` flag when running node-gyp configure. ```shell session $ node-gyp configure -- -Ddht_verbose=true ``` ### Appendix A: Quick Node.js installation guide There are many ways you can get Node.js installed on your Raspberry Pi. Here is just one of way you can do it. ```shell session $ wget https://nodejs.org/dist/v14.15.4/node-v14.15.4-linux-armv7l.tar.xz $ tar xvfJ node-v14.15.4-linux-armv7l.tar.xz $ sudo mv node-v14.15.4-linux-armv7l /opt $ sudo update-alternatives --install /usr/bin/node node /opt/node-v14.15.4-linux-armv7l/bin/node 1 $ sudo update-alternatives --set node /opt/node-v14.15.4-linux-armv7l/bin/node $ sudo update-alternatives --install /usr/bin/npm npm /opt/node-v14.15.4-linux-armv7l/bin/npm 1 ``` Please note that you may have to use armv6l instead of arm7l if you have an early Raspberry Pi model. ### References [1]: Node.js download - https://nodejs.org/en/download/ [2]: BCM2835 - http://www.airspayce.com/mikem/bcm2835/ [3]: Node.js native addon build tool - https://github.com/TooTallNate/node-gyp [4]: GPIO: Raspbery Pi Models A and B - https://www.raspberrypi.org/documentation/usage/gpio/