Test Harness for Pololu QTR Library
Dependencies: PololuQTRSensors mbed
Diff: main.cpp
- Revision:
- 0:4a43061bfa34
- Child:
- 1:f3aee4ff2b19
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Tue Aug 25 02:50:22 2015 +0000 @@ -0,0 +1,112 @@ +#include "mbed.h" +#include "QTRSensors.h" +#define NUM_SENSORS 7 +Serial pc(USBTX, USBRX); + +DigitalOut myled(LED1); + +// create an object for four QTR-xRC sensors on digital pins 0 and 9, and on analog +// inputs 1 and 3 (which are being used as digital inputs 15 and 17 in this case) + +QTRSensorsAnalog qtra((PinName[]) {A5, A4, A3, A2, A1, A0, PA_3}, NUM_SENSORS, 4, D7); +// PA_3, PA_2, PA_10, PB_3, PB_5, PB_4, PB_10 + +void setup(void); +void readSensors(void); +void readSensorsPlain(void); + +int main() { + pc.printf("Setup!\r\n"); + setup(); + pc.printf("Start Loop!\r\n"); + while(1) { + pc.printf("Read Sensors!\r\n"); + readSensorsPlain(); + } +} + +void setup() +{ + // optional: wait for some input from the user, such as a button press + + // then start calibration phase and move the sensors over both + // reflectance extremes they will encounter in your application: + int i; + for (i = 0; i < 50; i++) // make the calibration take about 5 seconds + // originally i < 250 + { + pc.printf("Calibrate Session %d\r\n",i); + qtra.calibrate(QTR_EMITTERS_ON); + wait_ms(20); + } + + for (i = 0; i < NUM_SENSORS; i++) + { + pc.printf("Min On %d \r\n", qtra.calibratedMinimumOn[i]); + } + + // optional: signal that the calibration phase is now over and wait for further + // input from the user, such as a button press +} + +void readSensors() +{ + unsigned int sensors[NUM_SENSORS]; + // get calibrated sensor values returned in the sensors array, along with the line position + // position will range from 0 to 2000, with 1000 corresponding to the line over the middle + // sensor. + int position = qtra.readLine(sensors); + + // if all three sensors see very low reflectance, take some appropriate action for this + // situation. + if (sensors[0] > 750 && sensors[1] > 750 && sensors[2] > 750) + { + // do something. Maybe this means we're at the edge of a course or about to fall off + // a table, in which case, we might want to stop moving, back up, and turn around. + pc.printf("do something. Maybe this means we're at the edge of a course or about to fall off a table, in which case, we might want to stop moving, back up, and turn around."); + + //return; + } + + // compute our "error" from the line position. We will make it so that the error is zero + // when the middle sensor is over the line, because this is our goal. Error will range from + // -1000 to +1000. If we have sensor 0 on the left and sensor 2 on the right, a reading of + // -1000 means that we see the line on the left and a reading of +1000 means we see the + // line on the right. + int error = position - 1000; + + int leftMotorSpeed = 200; + int rightMotorSpeed = 200; + if (error < -500) // the line is on the left + leftMotorSpeed = 20; // turn left + if (error > 500) // the line is on the right + rightMotorSpeed = 20; // turn right + + pc.printf("Left Motor %d, Right Motor %d\r\n", leftMotorSpeed, rightMotorSpeed); + myled = 1; // LED is ON + wait_ms(leftMotorSpeed); // 200 ms + myled = 0; // LED is OFF + wait(rightMotorSpeed); // 1 sec + + + // set motor speeds using the two motor speed variables above +} + + +void readSensorsPlain() +{ + unsigned int sensors[NUM_SENSORS]; + // get calibrated sensor values returned in the sensors array, along with the line position + // position will range from 0 to 2000, with 1000 corresponding to the line over the middle + // sensor. + pc.printf("before\r\n"); + qtra.readCalibrated(sensors, QTR_EMITTERS_ON); + pc.printf("after\r\n"); + + for (unsigned int i = 0; i < NUM_SENSORS; i++) { + + pc.printf("Sensor Value[%d] %d Min %d Max %d \r\n", i, sensors[i], qtra.calibratedMinimumOn[i], qtra.calibratedMaximumOn[i]); + + } + // set motor speeds using the two motor speed variables above +} \ No newline at end of file