LA CROSSE® TECHNOLOGY SPLASH PROOF ATOMIC CLOCK WITH OUTDOOR TEMPERATURE/HUMIDITY QUICK START GUIDE MODEL: 515-1912 DC: 021818 Full manual can be found under the Support tab here: bit. POWER UP 1. Insert 2-AA batteries into your Outdoor Sensor. 2. Insert 2-AA batteries inch your Atomic Clock. 3. Configure basic Settings. 4. Once the sensor is reading to your clock, place sensor outside in a shaded location.