diff --git a/oil_sensor/include/SonarSensor.h b/oil_sensor/include/SonarSensor.h
index 4e12a94..e7ce3ba 100644
--- a/oil_sensor/include/SonarSensor.h
+++ b/oil_sensor/include/SonarSensor.h
@@ -13,7 +13,7 @@ class SonarSensor : public GenericSensor {
   public:
     SonarSensor(short id) : GenericSensor(id) {}
 
-    unsigned long scan() {
-        return sonar.ping_median();
+    unsigned int scan() {
+        return sonar.convert_cm(sonar.ping_median());
     }
 };
diff --git a/oil_sensor/src/oil_sensor.cpp b/oil_sensor/src/oil_sensor.cpp
index 1992b6c..1e30a50 100644
--- a/oil_sensor/src/oil_sensor.cpp
+++ b/oil_sensor/src/oil_sensor.cpp
@@ -15,6 +15,7 @@ volatile bool shouldSend = true;
 
 void setup() {
 	TinySwitch::setup(SENDER);
+	delay(10000);
 	TinyPower::setup();
 	TinyPower::enableWdt(WDTO_8S);
 }
@@ -22,13 +23,12 @@ void setup() {
 void loop() {
 	if (shouldSend) {
 		shouldSend = false;
-		unsigned long distance = oilSensor.scan();
+		unsigned int distance = oilSensor.scan();
 		if (distance) {
-			if (counter % SEND_VCC_INTERVAL == 0) {
-				oilSensor.sendValueAndVoltage(distance);
-				counter = 0;
-			} else {
+			if (counter) {
 				oilSensor.sendValue(distance);
+			} else {
+				oilSensor.sendValueAndVoltage(distance);
 			}
 		}
 	}
@@ -37,7 +37,10 @@ void loop() {
 
 ISR(WDT_vect) {
 	counter++;
-	if (((counter + 1) % SEND_INTERVAL == 0) || ((counter + 1) % SEND_VCC_INTERVAL == 0)) {
+	if ((counter % SEND_INTERVAL == 0)) {
 		shouldSend = true;
+		if ((counter % SEND_VCC_INTERVAL == 0)) {
+			counter = 0;
+		}
 	}
 }