                                   // pin 7: bottom right outlet
 #define START_PIN_DS18B20_SNSRS 8
 #define START_PIN_DHT22_SNSRS   9
+#define START_PIN_HCSR04_SNSRS  10
 
 #define NUM_RELAY_SWTCHS  6 // 4 general purpose relays + 'kill switch' + grow bed valve
 #define NUM_DS18B20_SNSRS 2

    Serial.println(g_ds18b20_sensor.get_status_str());  
}



    // initialize DS18B20 "one wire" probes
    g_ds18b20_sensor.set_name(DSB18B20_SNSR_NAME_PREFIX);
    g_ds18b20_sensor.set_pin(START_PIN_DS18B20_SNSRS);
    
    // initialize HC-SR04 ultrasonic distance sensor:
    g_sr04_sensor.set_name(SR04_SNSR_NAME_PREFIX);
    g_sr04_sensor.set_pin(START_PIN_HCSR04_SNSRS);
}

void loop()
