--- /dev/null
+/*
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+int right_echo_pin = 6;
+int right_trigger_pin = 7;
+
+int left_echo_pin = 11;
+int left_trigger_pin = 12;
+
+int right_ping_microseconds = 0;
+int left_ping_microseconds = 0;
+double sound_cm_per_microsecond_at_sea_level = 0.034029;
+int count = 0;
+
+void on(int pin){
+ digitalWrite(pin, HIGH);}
+
+void off(int pin){
+ digitalWrite(pin, LOW);}
+
+int ping(int trigger, int echo){
+ int ping_time = 0;
+ // turn off trigger
+ off(trigger);
+ delayMicroseconds(2);
+ // turn on the trigger and leave it on long enough for the
+ // sonar sensor to notice
+ on(trigger);
+ delayMicroseconds(10);
+ off(trigger);
+ ping_time = pulseIn(echo, HIGH);
+ if(ping_time <= 0){
+ ping_time = 3000;}
+ // sonar needs some time to recover before pinging again,
+ // so make sure it gets enough sleep right here. 50 milliseconds
+ delay(50);
+ return ping_time;}
+
+void setup(){
+ Serial.begin(9600);
+ pinMode(right_echo_pin, INPUT);
+ pinMode(right_trigger_pin, OUTPUT);
+ pinMode(left_echo_pin, INPUT);
+ pinMode(left_trigger_pin, OUTPUT);}
+
+void loop(){
+ right_ping_microseconds = ping(right_trigger_pin, right_echo_pin);
+ left_ping_microseconds = ping(left_trigger_pin, left_echo_pin);
+ // print out the pulse time
+ Serial.print(right_ping_microseconds);
+ Serial.print(" = right ping microseconds, ");
+ Serial.print(left_ping_microseconds);
+ Serial.print(" = left ping microseconds. #");
+ Serial.println(count++);
+
+ // wait so it's easier to read the serial monitor.
+ // change delay to 0 for fullspeed.
+ // default is 333, which is about 1/3 of a second
+ delay(333);}