GrovePi for Node.js

GrovePi is an open source platform for connecting Grove Sensors to the Raspberry Pi.

Quick start

Before to start you should install Node.js on your RaspberryPi and clone the repo on your local environment. Be sure to have npm installed and then you can proceed installing the package. To install node.js you can do the following:

curl -sL https://deb.nodesource.com/setup_7.x | sudo -E bash -
sudo apt-get install nodejs

Go inside your Node.js application folder and type

$ npm install grovepi

Now you can include the module inside your application:

var GrovePi = require('grovepi').GrovePi

At this point you may need to include the GrovePi base classes:

var Commands = GrovePi.commands
var Board = GrovePi.board

If the sensor/component you need to use already has the classes then you can include them:

var AccelerationI2cSensor = GrovePi.sensors.AccelerationI2C
var UltrasonicDigitalSensor = GrovePi.sensors.UltrasonicDigital
var AirQualityAnalogSensor = GrovePi.sensors.AirQualityAnalog
var DHTDigitalSensor = GrovePi.sensors.DHTDigital
var LightAnalogSensor = GrovePi.sensors.LightAnalog
var DigitalButtonSensor = GrovePi.sensors.DigitalButton
var LoudnessAnalogSensor = GrovePi.sensors.LoudnessAnalog
var RotaryAngleAnalogSensor = GrovePi.sensors.RotaryAnalog

Now you can instantiate the GrovePi and your sensors/components, for example:

var board = new Board({
    debug: true,
    onError: function(err) {
      console.log('Something wrong just happened')
      console.log(err)
    },
    onInit: function(res) {
      if (res) {
        console.log('GrovePi Version :: ' + board.version())

        var lightSensor = new LightAnalogSensor(2)
        console.log('Light Analog Sensor (start watch)')
        lightSensor.on('change', function(res) {
          console.log('Light onChange value=' + res)
        })
        lightSensor.watch()
      }
    }
  })

If there is no class for your sensors or components then you can write your own functions for them: Note: every custom function must be called only after the Board init.

function customAccelerationReading() {
  var write = board.writeBytes(Commands.acc_xyz.concat([Commands.unused, Commands.unused, Commands.unused]))
  if (write) {
    board.wait(100)
    board.readByte()
    var bytes = board.readBytes()
    if (bytes instanceof Buffer) {
      var x = bytes[1] > 32 ? -(bytes[1]-224) : bytes[1]
      var y = bytes[2] > 32 ? -(bytes[2]-224) : bytes[2]
      var z = bytes[3] > 32 ? -(bytes[3]-224) : bytes[3]
      return [x, y, z]
    } else {
      return false
    }
  } else {
    return false
  }
}

When you are ready to go you should call the init method

board.init()

Each sensor/component has at least 3 methods to get access to the data:

• read() - Read data from the sensor/component
• stream(delay, callback) - Start a stream with the sensor/component, each N milliseconds (delay) sends data to the callback. You can use stopStream() to close the connection.
• watch(delay) - Start a polling routine which will fire a "change" event only when there are new data coming from the sensor/component. The internal timer will use the given delay value or 100 milliseconds as default. You can use stopWatch() to stop the polling.

And 1 method to write data:

• write(value) - Write a value on the sensor/component

Some sensors expose additional methods

• DigitalButton sensor exposes a down event which has a single argument on the callback. This argument will have the value *singlepress or longpress, depending on how long the user has been pressing the button.
• RotaryAngleAnalogSensor overrides the read method to provide noise-less output, since there are cases in which the sensor may incorrectly report that its value has changed. The sensor will return a value from 0 to 100. User also needs to call the start method for this sensor.
• LoudnessAnalogSensor provides a readAvgMax method which will return average and maximum values coming from the sensor for a period of time. This period restarts every time you call the readAvgMax method, so it is supposed that the method is called repeatedly in a timely manner (e.g. with a setInterval callback). User has to call the start method for the monitoring to begin.

You'll find more complex examples in the "basicTest.js" file under the "tests" folder of the repository.

License

The MIT License (MIT)

GrovePi for the Raspberry Pi: an open source platform for connecting Grove Sensors to the Raspberry Pi. Copyright (C) 2017 Dexter Industries

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.