Output device
A. What are Output Devices?
Output devices are hardware that help computers communicate with us by displaying or producing information. In simple terms, they take the data from the computer and turn it into something we can see, hear, or feel.
B. Touch Sensor with LED
The outcome I was aiming for was simple: when I touched the sensor, the LED should turn on, and when I removed my finger, the LED should turn off. It was a basic way to link an input (the sensor) with an output (the LED).
Connections
I connected the touch sensor to my PCB board so that it could detect my touch.
| Component | XIAO RP2040 Pin | Notes |
|---|---|---|
| Touch Sensor VCC | 3.3V | Power supply for the sensor |
| Touch Sensor GND | GND | Ground connection for the sensor |
| Touch Sensor OUT | D2 (GPIO2) | Digital input pin for touch sensor |
| LED Anode (+) | D3 (GPIO3) | Output pin to control LED |
| LED Cathode (-) | GND | Ground connection for the LED |
Then, I connected an LED to the PCB board, which is the output device. The idea was that the LED would light up when the sensor was touched.
I wrote a program to make the LED turn on or off depending on whether the touch sensor was activated.
This was just to try out simple functioning output on my PCB Board.
C. Servo Motor Positioning
The goal was to get the servo motor to rotate to a specific angle when triggered. This worked out well, and I was able to control the servo's movement through the signals from the PCB board.
Connections
Connected the servo motor to my PCB board, so it could move based on signals from the board.
| Servo Motor Pin | XIAO RP2040 Pin | Notes |
|---|---|---|
| VCC (Red) | 3.3V or 5V (if external) | 5V (for MG995) |
| GND (Black/Brown) | GND | GND |
| Signal (Yellow/Orange) | GPIO3 (or any PWM pin) | - |
The whole reason I kept things simple at first was because I wanted to test things directly on the PCB board and make sure everything was working before adding any complexity. By using basic devices like the touch sensor, LED, and servo motor, I was able to see how input and output devices interacted in a real-world setup. Testing on the board made everything so much easier to troubleshoot and adjust, which helped me learn how each component worked in action.
D. Connecting NeoPixel Ring
I wanted to make my NeoPixel Ring glow using an RP2040 board (Raspberry Pi Pico). Turns out, it’s pretty simple once you know what to do!
Connections
| NeoPixel Ring Pin | RP2040 Pin | Notes |
|---|---|---|
| DIN (Data In) | GP6 | Data pin for NeoPixel Ring |
| VCC (Power) | 3.3V or 5V | Power supply for NeoPixel (choose 5V for more brightness) |
| GND (Ground) | GND | Ground connection |
What was Next?
1.Made each LED light up one by one (looked like a moving dot ).
2.Changed colors from red to green to blue in a loop.
3.Made a smooth rainbow effect (this looked SO good!).
4.Tried a random color sparkle effect—it was super fun!
E. TM1637 Multiplication Displaying
Instead of using a clock, I decided to focus on multiplication for this project. I wanted to play around with numbers and show how they multiply, which could have practical uses like teaching multiplication, creating math games, or even for interactive displays in educational tools or apps. It was a fun way to experiment
Connections
| TM1637 Pin | RP2040 Pin | Notes |
|---|---|---|
| CLK (Clock) | GP2 | Clock signal for the TM1637 (for data transfer) |
| DIO (Data) | GP3 | Data signal for communication with the TM1637 |
| VCC | 3.3V | Power supply to the TM1637 (usually 3.3V) |
| GND | GND | Ground connection |
F. Text on 8x8 Matrix
I’d use an 8x8 LED matrix to create cool pixel art and make things blink, like I’m in a retro video game! I started by experimenting with writing text and seeing how it looked on the display.
Connections
| MAX7219 Pin | RP2040 Pin | Notes |
|---|---|---|
| VCC | 3.3V or 5V | Power supply to the MAX7219 (choose 5V for higher brightness) |
| GND | GND | Ground connection |
| DIN (Data) | GP3 | Data input pin for communication with MAX7219 |
| CS (Chip Select) | GP4 | Chip select pin for selecting the MAX7219 |
| CLK (Clock) | GP5 | Clock pin for serial data transfer to the MAX7219 |
About the Codes
Most of the codes I used in my projects were ChatGPT-tied. It made things a lot easier, but I still had to tweak a few things—changing pin numbers, adjusting for my board, and making sure everything actually worked. It’s a great support, but you can’t just copy-paste and expect it to run perfectly.
I realized it’s more important to understand how things work rather than just getting the code. Like:
Power matters – Some components say they work on 3.3V, but they run much better on 5V. Always check.
Signal levels – The RP2040 runs on 3.3V logic, so if a module expects 5V, a level shifter might be needed.
Polling vs. interrupts – If I keep checking a sensor in the loop, it slows things down. Interrupts are way more efficient.
Library choice – Not all libraries are the same. Some are lightweight, some have extra features. Picking the right one makes a difference.
Making it my own – Sure, I can display numbers on an LED matrix, but what if I want it to scroll? Or detect patterns on a touch sensor instead of just ON/OFF?
So yeah, getting code from ChatGPT is just the start. The real work is understanding it and making it work for my project.