Lab 04 - Blinking an LED

Student Information

Ewan Pedersen CS2210 10 • 09 • 2024

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6. Add a yellow LED that is ON while the red LED is OFF (alternating LEDs). Take a picture of your completed circuit on the breadboard, connected to your pi.

Screenshot

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7. What is the current in milliamps?

Ohm’s Law:

$$I=\frac{V_{supply}-V_{forward,red}}{R}Substitutingthevalues:$$

Red LED:

• $V_{supply}=3.3V$
• $V_{forward,red}=2.0V$
• $R=220ohms$

Plugging in values:

$$I_{red}=\frac{3.3V-2.0V}{220\Omega }=\frac{1.3V}{220\Omega }=0.00591\text{A}=5.91\text{mA}$$

Yellow LED:

• $V_{supply}=3.3V$
• $V_{forward,yellow}=2.1V$
• $R=220ohms$

Plugging in values:

$$I_{yellow}=\frac{3.3V-2.1V}{220\Omega }=\frac{1.2V}{220\Omega }=0.00545\text{A}=5.45\text{mA}$$

Results:

$RED=5.91mA$ $YELLOW=5.45mA$

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8. Use https://www.lucidchart.com (free account with a .edu email address), or https://www.draw.io to create a circuit diagram of your final circuit (with both LEDs). Take a screenshot of your diagram.

You can’t see it from the screenshot, but the glow follows your cursor as you hover over the card.

Screenshot

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Completed Code from Steps 5 and 6

Since I am on a Raspberry Pi 5 and not 4, the code had to be changed a bit during troubleshooting, so might be a bit unconventional.

Step 5:

Screenshot

Step 6:

Screenshot