Switches and Relays
Now lets cover some key components for the course (and electronics in general): switches and relays. We will begin with switches as relays are a more advanced version of a switch. Switches are basically components used for toggling on/off portions of the circuit, by closing (or opening, depending on the switch) the circuit when pressed, and doing the opposite when released. There are many forms of switches: SPST (single-pole-single-throw), SPDT (single-pole-double-throw), DPDT (double-pole-double-throw), etc. A relay is a more advanced type of switch that uses a component called an inductor along with a type of switch mentioned above. When current flows through the inductor, it creates a magnetic field, which in turn attracts the switch, thus pulling it into a new position, toggling the state of the switch as long as the current holds. Below are pictures of a relay in use (the orange box).
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When the switch is not pressed, the top LED lights up. |
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However, when pressed, the switch causes current to flow, thus creating a magnetic field in the inductor, and toggling the state of the relay. Now the bottom LED is lit. |
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Now for a variant. By adding a capacitor, we can make a oscillator. |
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Relay Oscillator: A variant of the previous circuit. When the switch is pressed, the magnetic field's induced voltage in tandem with the capacitor causes the state of the relay to oscillate-meaning that it toggles states at high frequency; thus alternating between which LED is lit quite frequently. One of the LEDs appears brighter because it is turning on more often than the other. |
VEX
What this course will work up towards is the use of robotics. VEX is a brand of robotics products that aims at teaching the basics and advanced skills. Before we can begin building however, we needed to stop and first inventory a large portion of the parts (just to make sure we know what we're working with).
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Inside the box was a removable tray with many screws/bolts, and various other parts. |
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We see wheels and frame parts for the robot. |
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Above we see the antennae for the robot, some push-button sensors, and limit switches. |
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No moving robot is complete without sensors... |
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Or a large book to keep track of it all. |
After much time and effort, our first version of the robot is complete! We will come back to these later, after we learn another important tool to robotics: programming!
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