LEGO MINDSTORMS Robots Manual page 140

#define FORWARD_MESSAGE 16
#define SPIN_MESSAGE 17
#define STOP_MESSAGE 18
#define GRAB_MESSAGE 19
#define RELEASE_MESSAGE 20
#define HEARTBEAT_MESSAGE 21
#define HEARTBEAT_TIME 20
task main() {
SetSensor(SENSOR_1, SENSOR_LIGHT);
SetSensor(SENSOR_2, SENSOR_TOUCH);
SetSensor(SENSOR_3, SENSOR_TOUCH);
start lightWatcher;
start touchWatcher;
start heartbeat;
}
task touchWatcher() {
while (true) {
if (SENSOR_2 == 1) {
SendMessage (FORWARD_MESSAGE);
Wait(10);
until (SENSOR_2 == 0);
SendMessage (STOP_MESSAGE);
}
if (SENSOR_3 == 1) {
SendMessage (SPIN_MESSAGE);
Wait(10);
until (SENSOR_3 == 0);
SendMessage (STOP_MESSAGE);
}
}
}
#define TOLERANCE 3
int current;
int minimum;
int maximum;
int midline;
int lastArmMessage;
task lightWatcher() {
minimum = 100;
maximum = 0;
while (true) {
current = SENSOR_1;
if (current < minimum) minimum = current;
if (current > maximum) maximum = current;
midline = minimum + (maximum - minimum) / 2;
if (SENSOR_1 <= (midline - TOLERANCE) &&
lastArmMessage != RELEASE_MESSAGE) {
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