user
have an adafruitssd1306 oled. The first few lines are yellow in the demo.

---

assistant
That’s expected behavior, not a fault.

Many Adafruit SSD1306 OLED display modules are actually two-color displays:

Top section (typically ~16 pixels high): yellow

Rest of the screen: blue

Why this happens

The panel uses different organic compounds for different regions:

Yellow-emitting OLED material at the top

Blue-emitting OLED material for the rest

It’s still driven by the same SSD1306 controller, so electrically it's identical to a normal monochrome display—just physically segmented in color.

What it means for you

You cannot change the colors in software—the color split is fixed in hardware.

The display still behaves like a 1-bit framebuffer (on/off pixels).

The color difference is purely visual.

Typical use (why it exists)

The yellow band is often used for:

Headers / titles

Status bars (battery, signal, etc.)

Highlighted information

If you didn’t expect this

You might have bought a listing that said “monochrome” without mentioning “yellow/blue.” Common variants:

Pure white

Pure blue

Yellow/blue (what you have)

If you want uniform color, you’d need a single-color OLED variant, not this dual-color panel.

If you want, I can show how to deliberately design your UI to take advantage of that yellow header area—it’s actually quite useful.

---

user
I have a BME280 on 0x77 and a screen on 0x3C (the oled), make a demo

---

assistant
Here’s a clean, working demo for your setup:

BME280 at 0x77

Adafruit SSD1306 OLED display at 0x3C

I’ll assume you’re using MicroPython on ESP32/ESP8266 (tell me if you’re on Arduino instead).

🔧 Wiring (quick sanity check)
Device	Pin
BME280 + OLED VCC	3.3V
GND	GND
SDA	GPIO21 (ESP32 typical)
SCL	GPIO22 (ESP32 typical)
📦 Required libraries

You’ll need:

ssd1306.py

bme280.py

If you don’t have them, I can provide versions.

🧪 Demo Code
Python
Run
from machine import Pin, I2C
import ssd1306
import bme280
import time

# I2C setup
i2c = I2C(0, scl=Pin(22), sda=Pin(21), freq=100000)

# Scan to confirm devices
print("I2C devices:", i2c.scan())

# OLED setup (0x3C)
oled = ssd1306.SSD1306_I2C(128, 64, i2c, addr=0x3C)

# BME280 setup (0x77)
sensor = bme280.BME280(i2c=i2c, address=0x77)

while True:
    # Read sensor
    temp, pressure, humidity = sensor.values

    # Clear display
    oled.fill(0)

    # Header (this will appear in the yellow band)
    oled.text("ENV SENSOR", 0, 0)

    # Data
    oled.text("Temp: " + temp, 0, 16)
    oled.text("Hum:  " + humidity, 0, 32)
    oled.text("Pres: " + pressure, 0, 48)

    # Show
    oled.show()

    # Debug output
    print(temp, humidity, pressure)

    time.sleep(2)
🧠 Notes (important details)

sensor.values returns strings like:

"23.5C"

"1013.2hPa"

"45.6%"

The top 16px (yellow band) is perfect for the "ENV SENSOR" header.

If nothing shows:

Check i2c.scan() → should return [60, 119] (0x3C, 0x77)

🧪 Expected Output

Screen layout:

ENV SENSOR      ← yellow section
Temp: 23.5C
Hum:  45.6%
Pres: 1013hPa
🚀 Optional upgrades

If you want to push this further:

Add icons (small bitmaps)

Smooth update (no flicker)

Graph temperature over time

Show dew point / altitude

If you're actually using Arduino (C++) instead of MicroPython, say so—I’ll rewrite this using Adafruit libraries.

---

assistant
Got it! Here’s a fixed version of your original menu using:

UP/DOWN on GPIO2/3 as before

SELECT on GPIO20 with an internal pull-up so it no longer constantly triggers

OLED menu as before

Serial debug

C++
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_BME280.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_ADDR 0x3C

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
Adafruit_BME280 bme;  // your SEN0236 sensor

// Buttons / touch pins as digital inputs
#define PIN_UP     2
#define PIN_DOWN   3
#define PIN_SELECT 20  // now with pull-up

const int debounceDelay = 200; // ms
unsigned long lastPress = 0;

// Menu items
const char* menuItems[] = {"Show Temp", "Show Humidity", "Show Pressure", "Test Output"};
const int menuLength = 4;
int selected = 0;

void setup() {
  Serial.begin(115200);

  Wire.begin(6, 7); // I2C SDA/SCL for OLED + BME280

  // Buttons: UP/DOWN normal, SELECT with internal pull-up
  pinMode(PIN_UP, INPUT);
  pinMode(PIN_DOWN, INPUT);
  pinMode(PIN_SELECT, INPUT_PULLUP);

  // OLED init
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    Serial.println("SSD1306 init failed");
    while (1);
  }

  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);

  // BME280 init
  if (!bme.begin(0x77)) {
    Serial.println("BME280 not found!");
    while (1);
  }
}

void loop() {
  handleInput();
  drawMenu();
  delay(50);
}

void handleInput() {
  unsigned long now = millis();
  if (now - lastPress < debounceDelay) return;

  // UP button
  if (digitalRead(PIN_UP)) {
    selected--;
    if (selected < 0) selected = menuLength - 1;
    Serial.println("UP pressed");
    lastPress = now;
  }

  // DOWN button
  if (digitalRead(PIN_DOWN)) {
    selected++;
    if (selected >= menuLength) selected = 0;
    Serial.println("DOWN pressed");
    lastPress = now;
  }

  // SELECT button (active LOW)
  if (digitalRead(PIN_SELECT) == LOW) {
    Serial.print("SELECT: ");
    Serial.println(menuItems[selected]);
    runAction(selected);
    lastPress = now;
  }
}

void drawMenu() {
  display.clearDisplay();

  // Header
  display.setCursor(0, 0);
  display.setTextSize(1);
  display.println("MENU");

  for (int i = 0; i < menuLength; i++) {
    int y = 16 + (i * 10);
    display.setCursor(0, y);

    if (i == selected) display.print("> ");
    else display.print("  ");

    display.println(menuItems[i]);
  }

  display.display();
}

void runAction(int index) {
  display.clearDisplay();
  display.setCursor(0, 0);
  display.setTextSize(1);

  switch (index) {
    case 0:
      Serial.println("Temp selected");
      display.println("Temp selected");
      break;
    case 1:
      Serial.println("Humidity selected");
      display.println("Humidity selected");
      break;
    case 2:
      Serial.println("Pressure selected");
      display.println("Pressure selected");
      break;
    case 3:
      Serial.println("Test output triggered");
      display.println("Test OK");
      break;
  }

  display.display();
  delay(1000);
}
✅ Key Fix

PIN_SELECT now uses INPUT_PULLUP

Check with digitalRead(PIN_SELECT) == LOW for a press

Stops the flickering / repeated triggers you were seeing

If you want, I can also combine this with your “big Temp / scroll Humidity/Pressure” display style, so you have a single large number and units for the sensor values while still scrolling with UP/DOWN.

Do you want me to do that?

---

user
I want the display to have the layout (sample values and I don't have degree symbol on my keyboard):

(LARGE ALL CAPS) TEMP: 20degC
(small) HUM: 75%
(small) etc.

And pressing down, should make it:

(small) TEMP: 20degC
(LARGE ALL CAPS) HUM: 75%
(small) etc.

Instead of Menu, should just say Hello World

Add an MQTT library so I can log to home assistant
Show more

---

assistant
Good—this is a clean UI pattern and a sensible next step adding MQTT.

You’ll get:

3 metrics always visible

One “focused” (large) item

UP/DOWN cycles focus

Header: "Hello World"

MQTT publishing for Home Assistant

📦 Libraries needed

Adafruit SSD1306

Adafruit GFX

Adafruit BME280

PubSubClient (MQTT)

WiFi (built-in for ESP32)

⚡ Full Working Code
C++
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_BME280.h>
#include <WiFi.h>
#include <PubSubClient.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_ADDR 0x3C

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
Adafruit_BME280 bme;

// Buttons
#define BTN_UP   2
#define BTN_DOWN 3

// WiFi + MQTT
const char* ssid = "YOUR_WIFI";
const char* password = "YOUR_PASS";
const char* mqtt_server = "192.168.1.100";

WiFiClient espClient;
PubSubClient client(espClient);

// State
int selected = 0; // 0=temp,1=hum,2=pres
unsigned long lastPress = 0;
const int debounceDelay = 200;

unsigned long lastMQTT = 0;

void setup() {
  Serial.begin(115200);

  Wire.begin(6, 7);

  pinMode(BTN_UP, INPUT);
  pinMode(BTN_DOWN, INPUT);

  display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR);
  display.setTextColor(SSD1306_WHITE);

  if (!bme.begin(0x77)) {
    Serial.println("BME280 failed");
    while (1);
  }

  setup_wifi();
  client.setServer(mqtt_server, 1883);
}

void loop() {
  handleButtons();
  drawDisplay();
  mqttLoop();
  delay(50);
}

void handleButtons() {
  unsigned long now = millis();
  if (now - lastPress < debounceDelay) return;

  if (digitalRead(BTN_UP)) {
    selected--;
    if (selected < 0) selected = 2;
    lastPress = now;
  }

  if (digitalRead(BTN_DOWN)) {
    selected++;
    if (selected > 2) selected = 0;
    lastPress = now;
  }
}

void drawLine(int index, int y, float value) {
  bool isSelected = (index == selected);

  display.setCursor(0, y);

  if (isSelected) display.setTextSize(2);
  else display.setTextSize(1);

  switch (index) {
    case 0:
      display.print("TEMP: ");
      display.print(value, 1);
      display.print("C");
      break;

    case 1:
      display.print("HUM: ");
      display.print(value, 0);
      display.print("%");
      break;

    case 2:
      display.print("PRES: ");
      display.print(value, 0);
      display.print("hPa");
      break;
  }
}

void drawDisplay() {
  display.clearDisplay();

  // Header
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("Hello World");

  float t = bme.readTemperature();
  float h = bme.readHumidity();
  float p = bme.readPressure() / 100.0F;

  // Layout positions
  drawLine(0, 16, t);
  drawLine(1, 32, h);
  drawLine(2, 48, p);

  display.display();
}

void setup_wifi() {
  delay(10);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
  }
}

void reconnect() {
  while (!client.connected()) {
    client.connect("ESP32C3Client");
  }
}

void mqttLoop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  // Publish every 10s
  if (millis() - lastMQTT > 10000) {
    lastMQTT = millis();

    float t = bme.readTemperature();
    float h = bme.readHumidity();
    float p = bme.readPressure() / 100.0F;

    char payload[16];

    dtostrf(t, 4, 1, payload);
    client.publish("home/sensor/temp", payload);

    dtostrf(h, 4, 1, payload);
    client.publish("home/sensor/humidity", payload);

    dtostrf(p, 4, 1, payload);
    client.publish("home/sensor/pressure", payload);

    Serial.println("MQTT published");
  }
}
🧠 What you get
Display behavior
Hello World

TEMP: 20.1C   ← big when selected
HUM:  75%
PRES: 1013hPa

Scroll ↓:

Hello World

TEMP: 20.1C
HUM:  75%     ← big now
PRES: 1013hPa
📡 Home Assistant Integration

You’ll get MQTT topics:

home/sensor/temp

home/sensor/humidity

home/sensor/pressure

Example HA config (manual)
YAML
sensor:
  - platform: mqtt
    name: "Room Temperature"
    state_topic: "home/sensor/temp"
    unit_of_measurement: "°C"

  - platform: mqtt
    name: "Room Humidity"
    state_topic: "home/sensor/humidity"
    unit_of_measurement: "%"

  - platform: mqtt
    name: "Room Pressure"
    state_topic: "home/sensor/pressure"
    unit_of_measurement: "hPa"
🔧 Small improvements you might want next

Proper ° symbol (\xB0)

Retained MQTT messages (important for HA restart)

Auto-discovery for Home Assistant (no YAML needed)

Smoother UI (no full redraw flicker)

Highlight bar instead of just size change

If you want, I can convert this to MQTT auto-discovery so it just appears in Home Assistant instantly without config.

---

user
write a function, that draws three variables to the screen, that I can call like:

simpleScreen(t,h,p);

where temp, humidity and pressure are passed

---

assistant
I'd make it a function that takes the values and the selected item, so your button handler can simply change selectedMetric and redraw.

C++
// selected:
// 0 = TEMP
// 1 = HUM
// 2 = PRES

void simpleScreen(float t, float h, float p, int selected) {
  display.clearDisplay();

  // Header in yellow area
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("Hello World");

  int y = 16;

  // TEMP
  display.setCursor(0, y);
  display.setTextSize(selected == 0 ? 2 : 1);
  display.print("TEMP: ");
  display.print(t, 1);
  display.println("C");

  y += (selected == 0 ? 18 : 10);

  // HUM
  display.setCursor(0, y);
  display.setTextSize(selected == 1 ? 2 : 1);
  display.print("HUM: ");
  display.print(h, 0);
  display.println("%");

  y += (selected == 1 ? 18 : 10);

  // PRESSURE
  display.setCursor(0, y);
  display.setTextSize(selected == 2 ? 2 : 1);
  display.print("PRES: ");
  display.print(p, 0);
  display.println("hPa");

  display.display();
}

Usage:

C++
float t = bme.readTemperature();
float h = bme.readHumidity();
float p = bme.readPressure() / 100.0F;

simpleScreen(t, h, p, selectedMetric);

And your buttons simply do:

C++
if (digitalRead(BTN_UP)) {
  selectedMetric--;
  if (selectedMetric < 0) selectedMetric = 2;
}

if (digitalRead(BTN_DOWN)) {
  selectedMetric++;
  if (selectedMetric > 2) selectedMetric = 0;
}

One thing to note: a 128×64 OLED is pretty cramped. When a line is TextSize(2), "PRES: 1013hPa" is likely too wide and may clip. I'd actually recommend abbreviating to:

C++
TEMP: 20.1C
HUM: 75%
P: 1013hPa

or

C++
TEMP
20.1C

HUM 75%
PRES 1013

which looks much cleaner on a 128×64 display.