   tx_payload.setSoil(readSoil(vcc));
 
   // Power down the soil sensor.
-  digitalWrite(PIN_SENSOR_GND, LOW);
-
-  // Disconnect the light sensor.
-  // This insures that there is not a voltage higher than vcc
-  // on the external ADC, as the light sensor is a voltage source.
-  pinMode(PIN_SENSOR_GND, INPUT);
-  
+  digitalWrite(PIN_SENSOR_VCC, LOW);
+
   // Build the payload buffer.
   uint8_t payload_buf[tx_payload.size()];
   tx_payload.serialize(payload_buf);

  onewireSensors.begin();
  onewireSensors.getAddress(deviceAddress, 0);

  // Begin the external ADC.
  ads.begin();
}

  // Read the temperature while the aref settles.
  tx_payload.setTemperature(readTemperature());

  // Power up the soil sensor.
  digitalWrite(PIN_SENSOR_VCC, HIGH);
  
  tx_payload.setChargeMa(readSolarCurrent());
  tx_payload.setChargeMv(readSolarVolts());
