An Introduction To Squirrel Applications Example 2
In this example we will create an simple refrigerator monitoring application that takes synchronous readings from the temperature/humidity sensor and the internal light sensor. The light reading is used to determine if the refrigerator door is open or closed. The door status, temperature and humidity readings are sent to the cloud using the Initial State service. We will use a Hardware Abstraction Layer (HAL) to reference all hardware objects, and to organize our application code we will use a class. This code can be easily configured for use with an imp006 Breakout Kit, impExplorer Kit, impAccelerator Battery Powered Sensor Node or impC001 Breakout Board.
Beginner
This example will focus on writing Squirrel code. Please visit the Getting Started Guide on the Electric Imp Dev Center to learn how to configure your device with BlinkUp™ and how to use the Electric Imp IDE, impCentral™.
.HAL.nut file in the repository that matches your hardware.
// HARDWARE ABSTRACTION LAYER
// ---------------------------------------------------
// HAL's are tables that map human readable names to
// the hardware objects used in the application.
// Copy and Paste Your HAL here
ExplorerKit_001 <- {
"LED_SPI" : hardware.spi257,
"SENSOR_AND_GROVE_I2C" : hardware.i2c89,
"TEMP_HUMID_I2C_ADDR" : 0xBE,
"ACCEL_I2C_ADDR" : 0x32,
"PRESSURE_I2C_ADDR" : 0xB8,
"POWER_GATE_AND_WAKE_PIN" : hardware.pin1,
"AD_GROVE1_DATA1" : hardware.pin2,
"AD_GROVE2_DATA1" : hardware.pin5
}
// REMOTE MONITORING APPLICATION CODE
// ---------------------------------------------------
// Application code, take readings from our sensors
// and send the data to the agent
class Application {
// Time in seconds to wait between readings
static READING_INTERVAL_SEC = 30;
// Accelerometer data rate in Hz
static ACCEL_DATARATE = 1;
// Hardware variables
i2c = ExplorerKit_001.SENSOR_AND_GROVE_I2C;
tempHumidAddr = ExplorerKit_001.TEMP_HUMID_I2C_ADDR;
pressureAddr = ExplorerKit_001.PRESSURE_I2C_ADDR;
accelAddr = ExplorerKit_001.ACCEL_I2C_ADDR;
// Sensor variables
tempHumid = null;
pressure = null;
accel = null;
constructor() {...}