The Raspberry Pi Pico is a versatile microcontroller that serves as the brain for a wide range of electronic projects. It excels at communicating with various components like LED lights, sensors, and displays, making it a perfect starting point for anyone interested in electronics.
To get started, your Pico needs two things: energy and instructions. You can power it in a couple of ways:
You can write instructions for the Pico using either MicroPython or C/C++. These instructions are saved as files directly on the Pico's memory (e.g., ledBlink.py, sensor.py).
To write and run your MicroPython programs, you'll need to connect the Pico to your laptop and use an IDE like Thonny. A special file named main.py will automatically run whenever the Pico is powered on, making it ideal for dedicated applications.
The Pico has a set of General-Purpose Input/Output (GPIO) pins that you can control. You can set the value of a pin to be high (1) or low (0).
When a pin is set to high, it outputs 3.3V. You can use this to power components like an LED. Remember to always use a resistor in series with the LED to limit the current, and connect the other end to a ground (GND) pin to complete the circuit.
The GPIO pins on the Pico are digital, meaning they can only be fully on or fully off. So how can you achieve something like dimming an LED to 50% brightness?
The answer is Pulse-Width Modulation (PWM). Instead of providing a constant lower voltage, we can switch the pin between 3.3V and 0V very quickly. For example, if we turn the pin on for half the time and off for the other half, the LED will appear to be at 50% brightness. This is because the switching is so fast that our eyes perceive the average voltage.
The percentage of time the signal is high is called the duty cycle. A 50% duty cycle, as in our example, results in 50% brightness. By adjusting the duty cycle, you can control the speed of a motor, the brightness of a light, and much more.