Radar sweep: ultrasonic on 10 and 11, servo on 12, on an Arduino Uno

// A radar: a servo sweeps an ultrasonic sensor and reports what it sees.
//
//   HC-SR04 VCC -> 5V   TRIG -> pin 10   ECHO -> pin 11   GND -> GND
//   servo signal -> pin 12   red -> 5V   brown -> GND
//
// At each degree of the sweep the sketch measures the distance and prints
// "angle,distance." on one line. A program on the computer reads those lines
// and draws the radar screen; here the serial monitor shows them.
//
// Drag the distance slider on the sensor while it sweeps.

#include <Servo.h>

const int TRIG = 10;
const int ECHO = 11;
const int SERVO_PIN = 12;

Servo turret;

long distanceCm() {
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);
  long echo = pulseIn(ECHO, HIGH, 30000UL);
  return echo / 58;
}

void report(int angle) {
  turret.write(angle);
  delay(30);
  Serial.print(angle);
  Serial.print(",");
  Serial.print(distanceCm());
  Serial.print(".");
  Serial.println();
}

void setup() {
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  turret.attach(SERVO_PIN);
  turret.write(90);
  Serial.begin(9600);
  Serial.println("Mokxi Uno: radar sweep, sensor on 10 and 11, servo on 12");
}

void loop() {
  for (int a = 15; a <= 165; a++) report(a);
  for (int a = 165; a > 15; a--) report(a);
}