Introduction To Squirrel Applications Example 1

ReadingASensor.agent.nut

// Reading a Sensor Agent Code
// ---------------------------------------------------

// CLOUD SERVICE LIBRARY
// ---------------------------------------------------
// Libraries must be included before all other code

// Initial State Library
#require "InitialState.class.nut:1.0.0"


// SETUP
// ---------------------------------------------------
// Set up an account with Initial State. Log in and 
// navigate to "my account" page.

// On "my account" page find/create a "Streaming Access Key"
// Paste it into the constant below
const STREAMING_ACCESS_KEY = ""; 

// Initialize Initial State
local iState = InitialState(STREAMING_ACCESS_KEY);

// The library will create a bucket using the agent ID 
// Let's log the agent ID here
local agentID = split(http.agenturl(), "/").top();
server.log("Agent ID: " + agentID);


// RUNTIME
// ---------------------------------------------------
server.log("Agent running...");

// Open listener for "reading" messages from the device
device.on("reading", function(reading) {
    // Log the reading from the device. The reading is a 
    // table, so use JSON encodeing method convert to a string
    server.log(http.jsonencode(reading));
    // Initial State requires the data in a specific structre
    // Build an array with the data from our reading.
    local events = [];
    events.push({"key" : "temperature", "value" : reading.temperature, "epoch" : time()});
    events.push({"key" : "humidity", "value" : reading.humidity, "epoch" : time()});

    // Send reading to Initial State
    iState.sendEvents(events, function(err, resp) {
        if (err != null) {
            // We had trouble sending to Initial State, log the error
            server.error("Error sending to Initial State: " + err);
        } else {
            // A successful send. The response is an empty string, so
            // just log a generic send message
            server.log("Reading sent to Initial State.");
        }
    })
})

ReadingASensor.device.nut

// Reading a Sensor Device Code
// ---------------------------------------------------

// SENSOR LIBRARY
// ---------------------------------------------------
// Libraries must be included before all other code

// Temperature Humidity sensor Library
#require "HTS221.device.lib.nut:2.0.1"


// SETUP
// ---------------------------------------------------
// The HTS221 library uses the sensor's i2c interface
// To initialize the library we need to configure the
// i2c and pass in the 12c address for our hardware.

// The i2c address for the Explorer Kits and the
// Battery Powered Sensor Node are all 0xBE.
const I2C_ADDR = 0xBE;

// Find the i2c for your hardware from the list below.
// Paste the hardware.i2c for your hardware into the
// i2c variable on line 32.

// imp006 Breakout Board Kit                   i2c = hardware.i2cLM
// impExplorer Dev Kit 001                     i2c = hardware.i2c89
// impExplorer Dev Kit 004m                    i2c = hardware.i2cNM
// impAccelerator Battery Powered Sensor Node  i2c = hardware.i2cAB
// impC001 Cellular Breakout Board Kit         i2c = hardware.i2cKL

// Configure i2c
// Paste your i2c hardware in the variable below
local i2c = hardware.i2cLM;
i2c.configure(CLOCK_SPEED_400_KHZ);

// Initialize the temperature/humidity sensor
local tempHumid = HTS221(i2c, I2C_ADDR);

// Before we can take a reading we need to configure
// the sensor. Note: These steps vary for different
// sensors. This sensor we just need to set the mode.

// We are going to set up the sensor to take a single
// reading when we call the read method.
tempHumid.setMode(HTS221_MODE.ONE_SHOT);


// APPLICATION FUNCTION(S)
// ---------------------------------------------------
// The sensor is now configured to taking readings.
// Lets set up a loop to take readings and send the
// result to the agent.

function loop() {
    // Take a reading
    local result = tempHumid.read();

    // Check the result
    if ("error" in result) {
        // We had an issue taking the reading, lets log it
        server.error(result.error);
    } else {
        // Let's log the reading
        server.log(format("Current Humidity: %0.2f %s, Current Temperature: %0.2f °C", result.humidity, "%", result.temperature));
        // Send the reading to the agent
        agent.send("reading", result);
    }

    // Schedule next reading in 10sec
    // Change the first parameter to imp.wakeup to
    // adjust the loop time
    imp.wakeup(10, loop);
}

// RUNTIME
// ---------------------------------------------------
server.log("Device running...");

// Start the readings loop
loop();