An Introduction To Squirrel Applications Example 6
In this example we will create a remote monitoring application that takes asynchronous sensor readings using Electric Imp’s Promise library. We will conserve power by putting the device to sleep between readings and connecting periodically to send the readings we have collected.
This code can be easily configured for use with an impExplorer™ Developer Kit (imp001 model only), impAccelerator™ Battery Powered Sensor Node or impC001 Breakout Board, each of which contains all the required sensors.
Advanced
This example will focus on writing Squirrel code. If you have not already done so, please visit the Getting Started Guide 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:
Copy and Paste the HAL table into the code in the HARDWARE ABSTRACTION LAYER section. Here is an example of what a HAL table will look like when inserted into the code. Note DO NOT copy and paste from this example; please use the HAL from Github.
// 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
}
Assign your hardware class variables. In the Application class before the constructor you will find a number of class variables. You will need to re-assign the hardware variables so they look something like the example below. Note DO NOT copy and paste from this example, as these values may differ from the ones in your HAL.
// POWER EFFICIENT 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;
// Time in seconds to wait between connections
static REPORTING_INTERVAL_SEC = 300;
// Max number of stored readings
static MAX_NUM_STORED_READINGS = 23;
// Time to wait after boot before disconnecting
static BOOT_TIMER_SEC = 60;
// Accelerometer data rate in Hz
static ACCEL_DATARATE = 1;
// Hardware variables
i2c = ExplorerKit_001.SENSOR_AND_GROVE_I2C; // Replace with your sensori2c
tempHumidAddr = ExplorerKit_001.TEMP_HUMID_I2C_ADDR; // Replace with your tempHumid i2c addr
accelAddr = ExplorerKit_001.ACCEL_I2C_ADDR; // Replace with your accel i2c addr
// Sensor variables
tempHumid = null;
accel = null;
// Message Manager variable
mm = null;
// Flag to track first disconnection
_boot = true;
constructor() {...}