in which Julia revisits PicoBlocks to interface with simple circuits
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| Breadboard-computer connection: wires through a microchip to a USB cable. |
Today we began our adventures assembling programmable circuitry with solderless breadboards! After spending many hours as a small child delightedly wiring batteries to power small fans and miniature lightbulbs, this was a source of much personal joy. I was especially enthused to interpret the pins of the microchip, as last semester I studied an IC chip for a materials science course at Olin (the source of the background, an SEM image of a 555 Timer IC). In this first introduction we interfaced with the circuit via the simple programming language PicoBlocks and a LogoChip; as shown below, we used several resistors and capacitors (as well as some switches) to change the color and brightness of a red-green bicolor LED.
With a similar circuit, we were later able to monitor the current flow with an oscilloscope. Adding a voltage regulator kept the voltage at about 2.5 V, the optimum level for the LogoChip (instead of the 3.3 V from fresh batteries). Adding a photosensor (which changes resistance depending on the incident photons) allowed further creativity in programming; we were able to match the computer's output from the photoresistor (measured via the input gate of the LogoChip) with the oscilloscope's current flow readings.
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| A simple LogoChip circuit to regulate current to the LED--can be programmed to brighten, dim, or flash LED. |
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| Adding the voltage regulator, photosensor, and oscilloscope leads to monitor the current.
Next lab: Thevenin's Good Idea--voltage dividers and fun with motors!
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