| 1 | /* |
| 2 | This program is free software: you can redistribute it and/or modify |
| 3 | it under the terms of the GNU Affero General Public License as |
| 4 | published by the Free Software Foundation, either version 3 of the |
| 5 | License, or (at your option) any later version. |
| 6 | |
| 7 | This program is distributed in the hope that it will be useful, |
| 8 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 9 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 10 | GNU Affero General Public License for more details. |
| 11 | |
| 12 | You should have received a copy of the GNU Affero General Public License |
| 13 | along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 14 | */ |
| 15 | int left_echo_pin = 11; |
| 16 | int left_trigger_pin = 12; |
| 17 | |
| 18 | int ping_microseconds = 0; |
| 19 | double sound_cm_per_microsecond_at_sea_level = 0.034029; |
| 20 | int count = 0; |
| 21 | |
| 22 | void setup(){ |
| 23 | Serial.begin(9600); |
| 24 | pinMode(left_echo_pin, INPUT); |
| 25 | pinMode(left_trigger_pin, OUTPUT);} |
| 26 | |
| 27 | void loop(){ |
| 28 | // make sure trigger pin is off, a.k.a. LOW |
| 29 | digitalWrite(left_trigger_pin, LOW); |
| 30 | delayMicroseconds(2); |
| 31 | |
| 32 | // send a 10 microsecond HIGH pulse to the trigger pin |
| 33 | digitalWrite(left_trigger_pin, HIGH); |
| 34 | delayMicroseconds(10); // leave the pin on for 10 microseconds |
| 35 | digitalWrite(left_trigger_pin, LOW); |
| 36 | |
| 37 | ping_microseconds = pulseIn(left_echo_pin, HIGH); |
| 38 | |
| 39 | // wait for the sonar sensor hardware to recover from pinging |
| 40 | delayMicroseconds(50); |
| 41 | |
| 42 | // print out the pulse time |
| 43 | Serial.print(ping_microseconds); |
| 44 | Serial.print(" = ping time (microseconds), "); |
| 45 | Serial.print(ping_microseconds * sound_cm_per_microsecond_at_sea_level / 2); |
| 46 | Serial.print(" = distance (cm). #"); |
| 47 | Serial.println(count++); |
| 48 | |
| 49 | // wait so it's easier to read the serial monitor. |
| 50 | // change delay to 0 for fullspeed. |
| 51 | // default is 333, which is about 1/3 of a second |
| 52 | delay(333);} |