ultrasound test results

arduino/src/ultrasonic.cpp

@@ -41,6 +41,7 @@ void us_transmit() {
 
   //set pin 2, 3 and 4 to output
   DDRD  |= 0b00011100;
+  PORTD &= 0b11100011;
 
   delayMicroseconds(2);