Output Devices

Group Assignment:

• measure the power consumption of an output device

Individual Assignment:

• add an output device to a microcontroller board you've designed and program it to do something

OLED

OLED is a self-illuminating display technology that provides superior image quality with perfect blacks, high contrast, and fast response times. It's widely used in premium displays but has limitations including potential burn-in and shorter lifespan compared to some alternatives. (From Claude, Prompt: What are OLED?)

I started by using an OLED from the fab inventory. It is very simple to connect VCC, GND, SDA, and SCL. But make sure you connect it correctly, as I did not and fried one screen. I plugged it in, went to connect my microcontroller, and then there was smoke and it was dead. Second try it worked, and I was able to display text on the screen. Next, I went to Claude and asked it to change the script I got from Adrian and made it count how many times I pressed a button. When I was about to take a video, the screen decided to stop working. Once I figure that out, I will add a video here.

(Video)

Here is the code

#include <U8g2lib.h>

// OLED display using SSD1306 driver
U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset= */ U8X8_PIN_NONE);

const int buttonPin = D7;  // Button connected to 3.3V
int buttonState = LOW;     // Current state of the button
int lastButtonState = LOW; // Previous state of the button
int pressCount = 0;        // Number of button presses
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;

void setup(void) {
  Serial.begin(115200);
  while (!Serial) {}
  delay(100);
  Serial.println("OLED Button Counter - Setup (3.3V logic)");

  pinMode(buttonPin, INPUT);  // For 3.3V button, use INPUT with external pulldown
  u8g2.begin();
}

void loop(void) {
  int reading = digitalRead(buttonPin);

  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading != buttonState) {
      buttonState = reading; 

      // Count only when button is pressed (HIGH)
      if (buttonState == HIGH) {
        pressCount++;
      }
    }
  }

  lastButtonState = reading;

  // Display on OLED
  u8g2.clearBuffer();
  u8g2.setFont(u8g2_font_ncenB08_tr);
  u8g2.drawStr(0, 10, "Puffin has entered:");
  char buf[20];
  snprintf(buf, sizeof(buf), "%d times", pressCount);
  u8g2.drawStr(0, 30, buf);
  u8g2.sendBuffer();

  delay(50);
}

E-ink

E-Ink is a paper-like display technology that uses electrically charged particles to create images, offering high readability and extremely low power consumption, but with slower refresh rates than conventional displays. (From Claude, Prompt: What is E-Ink?)

I used the E-Ink breakout board from Seeed. It was a bit of a hassle to get working. One thing to note here is the screen takes a while to update, so it confused me when nothing was happening, but I just had to wait a little bit. Also, you have to let the screen rest in between refreshes; otherwise, it will not turn white. I used this documentation from Seeed and the example clock script. Here is an image:

LoRa

LoRa is a long-range, low-power wireless technology designed for IoT applications that enables devices to communicate over several kilometers while maintaining battery life for years, though with limited data capacity compared to other wireless technologies. (From Claude, Prompt: What is Lora?)

To begin, I want to say that I am not a fan of LoRa. This was insanely frustrating to try to get working. We bought an M2 gateway from seed and that was simple to setup but after that i got sucked down a massive rabbit hole as there are so many different sites, different documentations, and different setups. I spent an entire day trying to get a Grove Wio E5 LoRa to work with a gateway. There is no good documentation that I have found, so I am kind of lost here. I don't know where to start and am kind of stuck in an endless loop. So if anyone knows of good documentation that explains LoRa, I would really appreciate it.