QTI line sensor demo

26Apr07

For my final for sensor workshop, lead by Jamie Allen, i took on the task of documenting the QTI line sensor by parallax. Here’s a link to the report, where you can find sample code.

Besides reporting on how the sensor works, we also had to demonstrate an application, and since this sensor can function both as analog(outputting values ranging from 0 -1023) and digital ( 1 or 0), i did both. For the former, i had it read 8 different gray values printed on two sheets of paper taped together and had those values read into Processing. Once in processing, the value was scaled to 255 and then subtracted from 255 since the IR receiver outputs white was 0 and black as an absence of reflection 255.

Thus, the color on the paper was presented on the screen with a corresponding sound output frequency as well, just for kicks, using the ESS library.

very exciting – mmmmmmm gray…

For the latter, I made a little two wheeled vehicle, controlled by an Arduino, switching two tip120 transistors to drive the little dc motors. The sensor, mounted on the front, switches when it read white, stops the motor and has it slowly turn left until it sees black again. Here a link to a QuicTime movie of it running.

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