Energia sketch to test a light sensor connected to an operational amplifier. The circuit is powered by enabling the P1.6 signal during TEST_MILLIS every EVERY_MILLIS in order to safe energy (TEST_MILLIS/EVERY_MILLIS fraction).

light_sensor_energy_safe.ino

// Energia sketch to test a light sensor connected to an operational amplifier. The circuit
// is powered by enabling the P1.6 signal during TEST_MILLIS every EVERY_MILLIS in
// order to safe energy (TEST_MILLIS/EVERY_MILLIS fraction).

#define POWER_LED GREEN_LED    /* green LED (LED2 on board) and P1.6 connected to the Vdd */
#define SENSOR_LED RED_LED     /* red LED (LED1 on board) */
#define SENSOR P1_7            /* pin P1.7 connected to Vout of the operational amplifier */

#define TEST_MILLIS      1     /* milliseconds that test is enabled */
#define EVERY_MILLIS     1000  /* milliseconds of the period of test */

void setup()
{
  pinMode(POWER_LED, OUTPUT);  // led is output
  pinMode(SENSOR_LED, OUTPUT); // led is output
  pinMode(SENSOR, INPUT);      // sensor is input
}

void loop()
{  
  digitalWrite(POWER_LED, HIGH);                 // power on the test
  delay(TEST_MILLIS);                            // wait while test is enabled
  digitalWrite(SENSOR_LED, digitalRead(SENSOR)); // enable the sensor led when sensor input is enabled
  digitalWrite(POWER_LED, LOW);                  // power off the test

  delay(EVERY_MILLIS-TEST_MILLIS);               // pause between tests
}