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Assignment 9 - Sensors, actuators and displays.This week was spent mostly working on my final project, so I don't have much sensor/actuator/display content for you. However, there are 2 items of interest for this page:
solenoids revisitedIn assignment 3, Axel and I learned how to drive solenoids. And I'm using them for my final project too. We figured out how to give them the current they need using the DRV101 solenoid driver, I made little PCB boards to drive them, but there was still one problem:Solenoids need to have something to pull them back into place after the current turns off - else they are likely to stick in the current-on position. Here's what JoeP had to say on the matter: Use a spring. That's how all of them essentially work. Or gravity.So what I did was to epoxy some little washers to the bottom of my solenoids. Then I could hook a spring through the washers, and hook the other end of the spring to some similar apparati underneath the solenoids. Here are some close-ups of how this all pans out:
ir sensorI have an IR sensor that kicks my great machine (see final project) into motion. From the manual:... consist(s) of an infared emitting diode and an NPN silicon phototransistor mounted side-by-side in black a plastic housing. The phototransistor reponds to radiation from the emitter only when a reflective object passes within its field of view...read the datasheet
To activate the sensor I have a little acrylic "fin" that dips down in front of it. The surface of the fin is apparently reflective enough to trigger the response from the phototransistor. However, a bright light will also trigger the response - so it probably won't work outside or in the path of a direct light.
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