1. The George Washington University Department of ECE ECE Intro: Electrical & Computer Engineering
Dr. S. Ahmadi
Class 4

2. Touch Sensors Is a type of digital sensor: - Returns a 0 if NOT hit
- Returns a 1 if HIT
- As with any digital sensor, it is either “ON” or “OFF”
- Digital sensors connect to digital ports (7-15) on the “lower deck” of the handyboard
(see diagram of the handyboard on the next slide)

3. Digital Ports

4. Touch Sensor Digital sensor
Connect to digital ports 8-15 on the KIPR Link
Access with function digital(port#)
1 indicates switch is closed
0 indicates switch is open

5. Utilizing the touch sensor to help robot turn intelligently
Write an IC program that does the following:
runs forward for an unspecified amount of time
detects a “hit” using a digital sensor attached to the front of the robot and then backs up (for x seconds --- you decide what number is best for x – HINT use a variable!)
Download and run

6. Simple Example To Use Bumpers
// Program to make a robot go forward.
// If hit detected, go backwards for 4 seconds.
int main() {
while( a_button()==0 ){ } // Waits for user to press start button.
while(1)
motor (1,70); // Turn on motor 3% of speed.
motor (3,70); // Turn on motor 3% of speed.
if ( digital(13)==1 ) // Check sensor connected to port
motor (1, -70); // Turn on motor 3% of speed in opposite direction.
motor (3, -70); // Turn on motor 3% of speed in opposite direction.
sleep(4); }
return 0

7. Classwork AA1FB int main() { } fd(2); sleep(3); bk(0); bk(2); ao();

8. Classwork AA2Sen int main(){ while(1){
printf("Sensor reading : %d\n", analog10(0));
msleep(500); }
return 0;

9. Classwork AA3FSenB_once int main(){ bk(0); bk(2);
int color_threshold = 200;
while(1){
if(analog10(0) > color_threshold &&
analog10(1) > color_threshold)
break;
fd(0);
fd(2);
msleep(100); }
bk(0);
bk(2);
sleep(2);
ao();
return 0; }

10. Classwork AA4FSenB_loop int main(){ int color_threshold = 200; bk(0);
while(1){
if(analog10(0) > color_threshold &&
analog10(1) > color_threshold)
break;
fd(0);
fd(2);
msleep(100); }
bk(0);
bk(2);
sleep(2);
ao();
msleep(100); }
return 0;

11. Classwork AA5SenB_three int main(){ int color_threshold = 200; bk(0);
int n = 1;
while(n <= 3){
while(1){
if(analog10(0) > color_threshold &&
analog10(1) > color_threshold)
break;
fd(0);
fd(2);
msleep(100); }
bk(0);
bk(2);
sleep(2);
ao();
n = n+1;
msleep(100); }
return 0;