Important information : Since ohm’s law tells us that I (current) = V (voltage) / R (ohm) rounding up the resistor value will lower the actual current being drawn a little. In this case we would round up to 100 ohm. To solve this we can either combine multiple resistors, or round up to a standard size. Unfortunately 80 ohm is not a standard size of a resistor. We can then calculate the resistor size needed to limit the current to the LED’s maximum forward current (IF) using ohm’s law like this: Additionally we need to know the output voltage of the Raspberry Pi which is 3.3V. A regular red LED has a forward voltage (VF) of 1.7V and forward current of 20mA (IF).
Specifically we need to find the forward voltage (VF) and the forward current (IF). To calculate the resistor value we need to examine the specifications of the LED. Without the resistor the LED would run at too high of a voltage, resulting in too much current being drawn which in turn would instantly burn the LED, and likely also the GPIO port on the Raspberry Pi. The resistor is used to limit the current that is being drawn and is called a current limiting resistor. The first step in this project is to design a simple LED circuit. Then we will make the LED circuit controllable from the Raspberry Pi by connecting the circuit to the general purpose input/output (GPIO) pins on the Raspberry Pi.Ī simple LED circuit consists of a LED and resistor. Raspberry Pi 3 setup with monitor and USB Mouse & Keyboard.
We will need the following tools to complete the project: This tutorial will guide you through setting up the circuit, connecting it to the Raspberry Pi and how to write the Python script that makes the LED blink. A great way to get started with electronics and the Raspberry Pi is hooking up a red LED and making it blink using a Python script.
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