And Done.

Dave and I finished our ece 315 lab today with the completion of the bench exam. It went fairly well, though it took us all but the last 3 minutes of the 3-hr timeslot to finish. Below is a video clip of our functional final project, er… functioning.

The idea was to drive the stepper motor at a rate of 10 steps per second, while flashing ‘0’ on the 7-segment display at a rate of 5 Hz. The stepper motor would turn until reaching the optical sensor, at which point it stops and allows the user to manually move it to a new position. When the pushbutton is pressed, the stepper motor turns back on and moves to the optical sensor again.

The cooler part was that on power-up, we also perfectly center the bar underneath the optical sensor by swinging back and forth to detect both edges. That looked really sweet but I didn’t think to record it. Oh well.

Here’s the final construction board after 6 labs’ worth of adding parts:

And here’s the aforementioned clip of the functioningness: (Requires QuickTime, or VLC, or something)

2 thoughts on “And Done.

  1. Colin M

    It controls a stepper motor by means of an optical sensor. First when you turn it on (not shown in video), it spins one way and then the other to calculate the exact width of the bar attached to the rotor. Then it turns off power to the motor, allowing you to turn it freely to any location. When you release the bar and press the pushbutton (shown in video), it spins the bar again until it breaks the optical sensor, taking steps at a 10 Hz (I think) rate, while flashing 0 on the 7-seg display at 5 Hz (or something like that). Not precisly useful, though I guess you could use it to automatically close a door or something, but that was the project we had to do for the bench exam, without preparation time to make an elaborate program. Pretty cool, nonetheless.

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