From 02f3df8c41c96a66ce2f3701760bd1fc8054fea6 Mon Sep 17 00:00:00 2001
From: Mateusz <mateusz.piecuch@yahoo.com>
Date: Mon, 5 Oct 2026 19:28:37 +0200
Subject: [PATCH] i2c fixes + server improvements

---
 server/app.py                      | 70 +++++++++++++++++++++---------
 server/templates/sensors.html      | 54 +++++++++++++++++++----
 thermo_sensor/main/CMakeLists.txt  |  2 +-
 thermo_sensor/main/thermo_sensor.c | 46 +++++++++++++++-----
 thermo_sensor/main/ygg_bmp280.c    | 34 ++++++++++++---
 thermo_sensor/main/ygg_bmp280.h    |  4 +-
 thermo_sensor/main/ygg_lock.c      | 40 +++++++++++++++++
 thermo_sensor/main/ygg_lock.h      | 15 +++++++
 thermo_sensor/main/ygg_sh1106.c    | 41 ++++++++++++++---
 9 files changed, 254 insertions(+), 52 deletions(-)
 create mode 100644 thermo_sensor/main/ygg_lock.c
 create mode 100644 thermo_sensor/main/ygg_lock.h

diff --git a/server/app.py b/server/app.py
index 25cd5c9..c968e2f 100644
--- a/server/app.py
+++ b/server/app.py
@@ -1,5 +1,6 @@
 import os
 from datetime import datetime, timedelta, timezone
+from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
 
 import click
 from flask import Flask, jsonify, redirect, render_template, request, url_for
@@ -10,7 +11,6 @@ from flask_login import (
     login_user,
     logout_user,
 )
-from sqlalchemy import func
 
 from models import Sensor, SensorReadout, User, db
 
@@ -137,37 +137,67 @@ def create_app():
     def api_sensor_readouts_hourly(sensor_id):
         type_ = request.args.get("type")
         range_ = request.args.get("range", "all")
+        # Frontend wysyła strefę czasową przeglądarki (np. Europe/Warsaw),
+        # żeby "today" znaczyło "od północy czasu lokalnego", a nie UTC.
+        tz_name = request.args.get("tz", "Europe/Warsaw") or "Europe/Warsaw"
+        try:
+            local_tz = ZoneInfo(tz_name)
+        except (ZoneInfoNotFoundError, ValueError):
+            return jsonify({"error": f"unknown timezone: {tz_name}"}), 400
         # Timestamps are stored as naive UTC, so the cutoff must be naive UTC too.
-        now = datetime.now(timezone.utc).replace(tzinfo=None)
+        now_utc = datetime.now(timezone.utc)
+        now_local = now_utc.astimezone(local_tz)
         if range_ == "today":
-            cutoff = now.replace(hour=0, minute=0, second=0, microsecond=0)
+            midnight_local = now_local.replace(hour=0, minute=0, second=0, microsecond=0)
+            cutoff = midnight_local.astimezone(timezone.utc).replace(tzinfo=None)
+        elif range_ == "24h":
+            cutoff = (now_utc - timedelta(hours=24)).replace(tzinfo=None)
         elif range_ == "week":
-            cutoff = now - timedelta(days=7)
+            cutoff = (now_utc - timedelta(days=7)).replace(tzinfo=None)
         elif range_ == "month":
-            cutoff = now - timedelta(days=30)
+            cutoff = (now_utc - timedelta(days=30)).replace(tzinfo=None)
         elif range_ == "all":
             cutoff = None
         else:
-            return jsonify({"error": "range must be one of: today, week, month, all"}), 400
-        query = (
-            db.session.query(
-                func.strftime("%Y-%m-%dT%H:00:00", SensorReadout.timestamp).label("hour"),
-                func.avg(SensorReadout.value).label("avg_value"),
-            )
-            .filter(SensorReadout.sensor_id == sensor_id)
+            return jsonify({"error": "range must be one of: today, 24h, week, month, all"}), 400
+        query = db.session.query(SensorReadout.timestamp, SensorReadout.value).filter(
+            SensorReadout.sensor_id == sensor_id
         )
         if cutoff is not None:
             query = query.filter(SensorReadout.timestamp >= cutoff)
         if type_:
             query = query.filter(SensorReadout.type == type_)
-        rows = (
-            query.group_by("hour")
-            .order_by("hour")
-            .all()
-        )
-        return jsonify(
-            [{"timestamp": r.hour, "value": round(r.avg_value, 2)} for r in rows]
-        )
+        rows = query.order_by(SensorReadout.timestamp).all()
+        # Zakresy today i 24h: wszystkie pomiary jako punkty, bez uśredniania.
+        if range_ in ("today", "24h"):
+            return jsonify(
+                [
+                    {
+                        "timestamp": ts.strftime("%Y-%m-%dT%H:%M:%S"),
+                        "value": value,
+                    }
+                    for ts, value in rows
+                ]
+            )
+        # Pozostałe zakresy: średnia godzinowa liczona po pełnej godzinie
+        # lokalnej (poprawne też przy zmianie DST), znacznik to początek
+        # godziny w UTC (frontend dokleja "Z").
+        buckets: dict[datetime, list[float]] = {}
+        for ts, value in rows:
+            ts_utc = ts.replace(tzinfo=timezone.utc)
+            hour_local = ts_utc.astimezone(local_tz).replace(
+                minute=0, second=0, microsecond=0
+            )
+            hour_utc = hour_local.astimezone(timezone.utc).replace(tzinfo=None)
+            buckets.setdefault(hour_utc, []).append(value)
+        result = [
+            {
+                "timestamp": hour.strftime("%Y-%m-%dT%H:00:00"),
+                "value": round(sum(values) / len(values), 2),
+            }
+            for hour, values in sorted(buckets.items())
+        ]
+        return jsonify(result)
 
     # --- API: device writes (intentionally public — called by devices/sensors) ---
 
diff --git a/server/templates/sensors.html b/server/templates/sensors.html
index 0a239b6..0271a96 100644
--- a/server/templates/sensors.html
+++ b/server/templates/sensors.html
@@ -35,6 +35,7 @@
         <label for="range-select">Range:</label>
         <select id="range-select">
             <option value="today">Today</option>
+            <option value="24h">Last 24h</option>
             <option value="week">Week</option>
             <option value="month">Month</option>
             <option value="all" selected>All</option>
@@ -44,6 +45,7 @@
 
     <div id="chart-section" class="hidden chart-box">
         <canvas id="chart"></canvas>
+        <p id="chart-info" class="desc"></p>
         <p id="chart-error" class="error hidden"></p>
     </div>
 
@@ -74,8 +76,13 @@
         const refreshButton = document.getElementById('refresh-button');
         const readoutsSection = document.getElementById('readouts-section');
         const readoutsBody = document.getElementById('readouts-body');
+        const chartInfo = document.getElementById('chart-info');
         let chart = null;
 
+        // Strefa czasowa przeglądarki — backend liczy "today" od północy
+        // w tej strefie (np. Europe/Warsaw = GMT+2 latem).
+        const userTz = Intl.DateTimeFormat().resolvedOptions().timeZone || 'Europe/Warsaw';
+
         // The page must keep working (dropdown + table) even if the
         // Chart.js CDN is unreachable — the chart is then simply skipped.
         if (window.Chart) {
@@ -87,12 +94,38 @@
 
         function formatTimestamp(iso) {
             const d = new Date(iso);
-            return d.toLocaleString('pl-PL', { timeZone: 'Europe/Warsaw' });
+            return d.toLocaleString('pl-PL', { timeZone: userTz });
         }
 
         function formatChartLabel(iso) {
             const d = new Date(iso + 'Z');
-            return d.toLocaleString('pl-PL', { timeZone: 'Europe/Warsaw', hour: '2-digit', minute: '2-digit', day: '2-digit', month: '2-digit', year: 'numeric' });
+            return d.toLocaleString('pl-PL', { timeZone: userTz, hour: '2-digit', minute: '2-digit', day: '2-digit', month: '2-digit', year: 'numeric' });
+        }
+
+        function chartInfoText(range) {
+            if (range === 'today') return `Raw measurements since local midnight (${userTz}) — no averaging.`;
+            if (range === '24h') return 'Raw measurements from the last 24 hours — no averaging.';
+            const period = range === 'week' ? 'the last 7 days'
+                : range === 'month' ? 'the last 30 days'
+                : 'all stored data';
+            return `Hourly averages over ${period} — each point is the mean of all measurements in that local hour (${userTz}).`;
+        }
+
+        // Ciśnienie jest składowane w bazie w paskalach (tak wysyła firmware),
+        // a wyświetlane w hektopaskalach z jednym miejscem po przecinku.
+        function displayValue(type, value) {
+            if (type === 'pressure') return Math.round(value / 10) / 10;
+            return value;
+        }
+
+        function formatTableValue(type, value) {
+            if (type === 'pressure') return (value / 100).toFixed(1) + ' hPa';
+            return value;
+        }
+
+        function yAxisTitle(type) {
+            if (type === 'pressure') return 'pressure (hPa)';
+            return type;
         }
 
         async function fetchJSON(url) {
@@ -143,11 +176,14 @@
 
             try {
                 // fetch hourly data for chart
-                const hourly = await fetchJSON(`/api/sensors/${sensorId}/readouts/hourly?type=${type}&range=${range}`);
+                const hourly = await fetchJSON(`/api/sensors/${sensorId}/readouts/hourly?type=${encodeURIComponent(type)}&range=${encodeURIComponent(range)}&tz=${encodeURIComponent(userTz)}`);
                 if (!hourly.length) throw new Error('no data for this range');
 
                 const labels = hourly.map(r => formatChartLabel(r.timestamp));
-                const values = hourly.map(r => r.value);
+                const values = hourly.map(r => displayValue(type, r.value));
+                // Przy zakresach today/24h punktów jest dużo (~1/min),
+                // więc mniejsze markery żeby wykres był czytelny.
+                const dense = range === 'today' || range === '24h';
 
                 if (chart) chart.destroy();
                 const ctx = document.getElementById('chart').getContext('2d');
@@ -164,15 +200,15 @@
                             pointBorderColor: '#55ffff',
                             fill: true,
                             tension: 0.3,
-                            pointRadius: 3,
+                            pointRadius: dense ? 1.5 : 3,
                         }]
                     },
                     options: {
                         responsive: true,
                         plugins: { legend: { display: false } },
                         scales: {
-                            x: { title: { display: true, text: 'Time (hourly avg)' } },
-                            y: { title: { display: true, text: type } }
+                            x: { title: { display: true, text: dense ? 'Time' : 'Time (hourly avg)' } },
+                            y: { title: { display: true, text: yAxisTitle(type) } }
                         }
                     }
                 });
@@ -180,9 +216,11 @@
                 // The chart was created while the container was hidden,
                 // so force a re-measure now that it is visible.
                 chart.resize();
+                chartInfo.textContent = '> ' + chartInfoText(range);
             } catch (err) {
                 chartError.textContent = '! Chart error: ' + err.message;
                 chartError.classList.remove('hidden');
+                chartInfo.textContent = '';
                 chartSection.classList.remove('hidden');
             }
         }
@@ -199,7 +237,7 @@
             const readouts = await fetchJSON(`/api/sensors/${sensorId}/readouts?type=${type}`);
             readouts.forEach(r => {
                 const tr = document.createElement('tr');
-                tr.innerHTML = `<td>${formatTimestamp(r.timestamp)}</td><td>${r.value}</td>`;
+                tr.innerHTML = `<td>${formatTimestamp(r.timestamp)}</td><td>${formatTableValue(type, r.value)}</td>`;
                 readoutsBody.appendChild(tr);
             });
             readoutsSection.classList.remove('hidden');
diff --git a/thermo_sensor/main/CMakeLists.txt b/thermo_sensor/main/CMakeLists.txt
index e661af0..c10f737 100644
--- a/thermo_sensor/main/CMakeLists.txt
+++ b/thermo_sensor/main/CMakeLists.txt
@@ -1,2 +1,2 @@
-idf_component_register(SRCS "thermo_sensor.c" "ygg_http_routes.c" "ygg_bmp280.c" "ygg_http_req.c" "ygg_state.c" "ygg_sh1106.c" "../common_esp32/ygg_wifi.c" "../common_esp32/ygg_http_server.c"
+idf_component_register(SRCS "thermo_sensor.c" "ygg_http_routes.c" "ygg_bmp280.c" "ygg_http_req.c" "ygg_state.c" "ygg_sh1106.c" "ygg_lock.c" "../common_esp32/ygg_wifi.c" "../common_esp32/ygg_http_server.c"
                        INCLUDE_DIRS "." "../common_esp32")
diff --git a/thermo_sensor/main/thermo_sensor.c b/thermo_sensor/main/thermo_sensor.c
index 5a14e3d..3ed6c73 100644
--- a/thermo_sensor/main/thermo_sensor.c
+++ b/thermo_sensor/main/thermo_sensor.c
@@ -3,9 +3,11 @@
 #include <freertos/task.h>
 #include <esp_system.h>
 #include <esp_timer.h>
+#include <esp_log.h>
 
 #include "nvs_flash.h"
 #include "esp_http_server.h"
+#include "i2cdev.h"
 
 #include "ygg_http_server.h"
 #include "ygg_http_routes.h"
@@ -15,6 +17,7 @@
 #include "ygg_http_req.h"
 #include "ygg_state.h"
 #include "ygg_sh1106.h"
+#include "ygg_lock.h"
 #include "lvgl.h"
 
 
@@ -25,7 +28,10 @@ bmp280_t dev_bmp_280;
 
 void lvgl_task(void *pvParameters) {
     while (1) {
-        lv_timer_handler();
+        if (ygg_lvgl_lock_take(pdMS_TO_TICKS(100))) {
+            lv_timer_handler();
+            ygg_lvgl_lock_give();
+        }
         vTaskDelay(pdMS_TO_TICKS(10));
     }
 }
@@ -34,19 +40,31 @@ void sensor_task(void *pvParameters) {
     // Wait 1s, to avoid corrupted first sensor readout
     vTaskDelay(pdMS_TO_TICKS(1000));
     while (1) {
-        ygg_bmp280_read_sensor(&dev_bmp_280);
+        esp_err_t err = ygg_bmp280_read_sensor(&dev_bmp_280);
         // Najpierw OLED, potem (blokujący) HTTP — żeby ekran
         // odświeżył się nawet gdy serwer nie odpowiada.
+        // ygg_bmp280_read_sensor() aktualizuje CURR_READOUT TYLKO przy
+        // sukcesie, więc przy błędzie pokazujemy ostatnie dobre + ERR
+        // i NIE wysyłamy śmieci do bazy.
         char buf[256];
-        snprintf(buf, sizeof(buf), "Temp: %.1f C\nHumid: %.1f %%\nPress: %.1f hPa",
-                 CURR_READOUT.temperature,
-                 CURR_READOUT.humidity,
-                 CURR_READOUT.pressure / 100.);
-        ygg_set_display_label(sh_display, label, buf);
-        ygg_send_sensor_readouts(BASE_URL,
-                                 SENSOR_NAME,
-                                 CURR_READOUT);
-        vTaskDelay(pdMS_TO_TICKS(10000));
+        if (err == ESP_OK) {
+            snprintf(buf, sizeof(buf), "Temp: %.1f C\nHumid: %.1f %%\nPress: %.1f hPa",
+                     CURR_READOUT.temperature,
+                     CURR_READOUT.humidity,
+                     CURR_READOUT.pressure / 100.);
+            ygg_set_display_label(sh_display, label, buf);
+            ygg_send_sensor_readouts(BASE_URL,
+                                     SENSOR_NAME,
+                                     CURR_READOUT);
+        } else {
+            snprintf(buf, sizeof(buf), "SENSOR ERR\nTemp: %.1f C\nHumid: %.1f %%\nPress: %.1f hPa",
+                     CURR_READOUT.temperature,
+                     CURR_READOUT.humidity,
+                     CURR_READOUT.pressure / 100.);
+            ygg_set_display_label(sh_display, label, buf);
+            ESP_LOGW(TAG, "skipping HTTP POST, keeping last good readout");
+        }
+        vTaskDelay(pdMS_TO_TICKS(60 * 1000));
     }
 }
 
@@ -77,6 +95,12 @@ void app_main()
     httpd_register_uri_handler(server, &ygg_press_uri);
     httpd_register_uri_handler(server, &ygg_hum_uri);
 
+    // Jedna centralna inicjalizacja: mutexy + magistrala I2C.
+    // Wcześniej i2cdev_init() był wołany w obu ygg_*_init() + bus był
+    // tworzony przez dummy-device OLED, co mieszało.
+    ygg_lock_init();
+    ESP_ERROR_CHECK(i2cdev_init());
+
     sh_display = ygg_sh1106_init();
 
     lv_obj_t *scr = lv_display_get_screen_active(sh_display);
diff --git a/thermo_sensor/main/ygg_bmp280.c b/thermo_sensor/main/ygg_bmp280.c
index fa37928..f37d062 100644
--- a/thermo_sensor/main/ygg_bmp280.c
+++ b/thermo_sensor/main/ygg_bmp280.c
@@ -1,29 +1,52 @@
 #include <stdio.h>
 #include <string.h>
 #include <bmp280.h>
+#include <esp_log.h>
 #include "ygg_bmp280.h"
 #include "ygg_state.h"
+#include "ygg_lock.h"
+
+static const char *TAG = "ygg_bmp280";
 
 void ygg_bmp280_init(bmp280_t *dev) {
-    ESP_ERROR_CHECK(i2cdev_init());
+    // UWAGA: i2cdev_init() + ygg_lock_init() robi app_main() raz przed
+    // wszystkimi initami. Tutaj już nie tworzymy magistrali.
     bmp280_params_t params;
     bmp280_init_default_params(&params);
     memset(dev, 0, sizeof(bmp280_t));
 
     ESP_ERROR_CHECK(bmp280_init_desc(dev, BMP280_I2C_ADDRESS_0, 0, I2C_MASTER_SDA, I2C_MASTER_SCL));
+    // bmp280_init_desc() ustawia 1MHz - za szybko na pająka + dzieloną
+    // magistralę z OLED. Zjeżdżamy do 100kHz przed pierwszym użyciem
+    // (device jest dopinane do busa leniwie przy pierwszej transakcji).
+    dev->i2c_dev.cfg.master.clk_speed = YGG_I2C_FREQ_HZ;
     ESP_ERROR_CHECK(bmp280_init(dev, &params));
 
     bool bme280p = dev->id == BME280_CHIP_ID;
     printf("BMP280: found %s\n", bme280p ? "BME280" : "BMP280");
 }
 
-void ygg_bmp280_read_sensor(bmp280_t *dev) {
-    float pressure, temperature, humidity;
+esp_err_t ygg_bmp280_read_sensor(bmp280_t *dev) {
+    float pressure = 0, temperature = 0, humidity = 0;
     bool bme280p = dev->id == BME280_CHIP_ID;
 
-    if (bmp280_read_float(dev, &temperature, &pressure, &humidity) != ESP_OK)
-        printf("Temperature/pressure reading failed\n");
+    // Cały odczyt pod wspólnym mutexem I2C - OLED (esp_lcd) używa
+    // tego samego busa bez wiedzy o mutexach i2cdev.
+    // Bez tego flush LVGL potrafi wejść w środek odczytu -> timeout.
+    if (!ygg_i2c_lock_take(pdMS_TO_TICKS(1000))) {
+        ESP_LOGW(TAG, "I2C busy, skipping readout");
+        return ESP_ERR_TIMEOUT;
+    }
+    esp_err_t err = bmp280_read_float(dev, &temperature, &pressure, &humidity);
+    ygg_i2c_lock_give();
 
+    if (err != ESP_OK) {
+        ESP_LOGW(TAG, "Temperature/pressure reading failed: %s - keeping last good readout",
+                 esp_err_to_name(err));
+        return err;
+    }
+
+    // Aktualizuj globalny stan TYLKO przy sukcesie.
     CURR_READOUT.temperature = temperature;
     CURR_READOUT.pressure = pressure;
     CURR_READOUT.humidity = humidity;
@@ -32,4 +55,5 @@ void ygg_bmp280_read_sensor(bmp280_t *dev) {
         printf(", Humidity: %.2f\n", humidity);
     else
         printf("\n");
+    return ESP_OK;
 }
diff --git a/thermo_sensor/main/ygg_bmp280.h b/thermo_sensor/main/ygg_bmp280.h
index 93fb73a..6b52087 100644
--- a/thermo_sensor/main/ygg_bmp280.h
+++ b/thermo_sensor/main/ygg_bmp280.h
@@ -2,11 +2,13 @@
 #define YGG_BMP280_H
 
 #include <bmp280.h>
+#include <esp_err.h>
 
 #define I2C_MASTER_SDA 19
 #define I2C_MASTER_SCL 23
+#define YGG_I2C_FREQ_HZ 100000
 
 void ygg_bmp280_init(bmp280_t *dev);
-void ygg_bmp280_read_sensor(bmp280_t *dev);
+esp_err_t ygg_bmp280_read_sensor(bmp280_t *dev);
 
 #endif
diff --git a/thermo_sensor/main/ygg_lock.c b/thermo_sensor/main/ygg_lock.c
new file mode 100644
index 0000000..7dd6d24
--- /dev/null
+++ b/thermo_sensor/main/ygg_lock.c
@@ -0,0 +1,40 @@
+#include "ygg_lock.h"
+#include <freertos/semphr.h>
+
+static SemaphoreHandle_t s_i2c_mutex = NULL;
+static SemaphoreHandle_t s_lvgl_mutex = NULL;
+
+void ygg_lock_init(void) {
+    if (s_i2c_mutex == NULL) {
+        s_i2c_mutex = xSemaphoreCreateMutex();
+    }
+    if (s_lvgl_mutex == NULL) {
+        s_lvgl_mutex = xSemaphoreCreateMutex();
+    }
+}
+
+bool ygg_i2c_lock_take(TickType_t timeout) {
+    if (s_i2c_mutex == NULL) {
+        return false;
+    }
+    return xSemaphoreTake(s_i2c_mutex, timeout) == pdTRUE;
+}
+
+void ygg_i2c_lock_give(void) {
+    if (s_i2c_mutex != NULL) {
+        xSemaphoreGive(s_i2c_mutex);
+    }
+}
+
+bool ygg_lvgl_lock_take(TickType_t timeout) {
+    if (s_lvgl_mutex == NULL) {
+        return false;
+    }
+    return xSemaphoreTake(s_lvgl_mutex, timeout) == pdTRUE;
+}
+
+void ygg_lvgl_lock_give(void) {
+    if (s_lvgl_mutex != NULL) {
+        xSemaphoreGive(s_lvgl_mutex);
+    }
+}
diff --git a/thermo_sensor/main/ygg_lock.h b/thermo_sensor/main/ygg_lock.h
new file mode 100644
index 0000000..17244c7
--- /dev/null
+++ b/thermo_sensor/main/ygg_lock.h
@@ -0,0 +1,15 @@
+#ifndef YGG_LOCK_H
+#define YGG_LOCK_H
+
+#include <freertos/FreeRTOS.h>
+#include <stdbool.h>
+
+void ygg_lock_init(void);
+
+bool ygg_i2c_lock_take(TickType_t timeout);
+void ygg_i2c_lock_give(void);
+
+bool ygg_lvgl_lock_take(TickType_t timeout);
+void ygg_lvgl_lock_give(void);
+
+#endif
diff --git a/thermo_sensor/main/ygg_sh1106.c b/thermo_sensor/main/ygg_sh1106.c
index f5fcb30..17a32b2 100644
--- a/thermo_sensor/main/ygg_sh1106.c
+++ b/thermo_sensor/main/ygg_sh1106.c
@@ -6,14 +6,19 @@
 #include "esp_lcd_panel_ops.h"
 #include "esp_timer.h"
 #include "esp_lcd_panel_sh1106.h"
+#include "esp_log.h"
+#include "ygg_bmp280.h"
+#include "ygg_lock.h"
 
 #define I2C_HOST I2C_NUM_0
-#define EXAMPLE_I2C_MASTER_FREQ_HZ 400000
+#define EXAMPLE_I2C_MASTER_FREQ_HZ YGG_I2C_FREQ_HZ
 #define EXAMPLE_LCD_V_RES              64
 #define EXAMPLE_LCD_H_RES              128
 #define EXAMPLE_LVGL_PALETTE_SIZE      8
-#define SH1106_I2C_SDA_GPIO            19
-#define SH1106_I2C_SCL_GPIO            23
+#define SH1106_I2C_SDA_GPIO            I2C_MASTER_SDA
+#define SH1106_I2C_SCL_GPIO            I2C_MASTER_SCL
+
+static const char *TAG = "ygg_sh1106";
 
 static uint8_t oled_buffer[EXAMPLE_LCD_H_RES * EXAMPLE_LCD_V_RES / 8];
 
@@ -51,8 +56,21 @@ static void example_lvgl_flush_cb(lv_display_t *disp, const lv_area_t *area, uin
             }
         }
     }
-    // pass the draw buffer to the driver
-    esp_lcd_panel_draw_bitmap(panel_handle, x1, y1, x2 + 1, y2 + 1, oled_buffer);
+    // pass the draw buffer to the driver.
+    // Cały transfer pod wspólnym mutexem I2C - BMP280 (i2cdev) używa
+    // tego samego busa. Bez tego odczyt sensora potrafi wejść w środek
+    // rysowania -> I2C hardware timeout po obu stronach.
+    // UWAGA: nie bierzemy tu mutexa LVGL - flush jest wołany z lvgl_task
+    // już pod mutexem LVGL (z lv_timer_handler). Branie go tu = deadlock.
+    if (ygg_i2c_lock_take(pdMS_TO_TICKS(1000))) {
+        esp_err_t err = esp_lcd_panel_draw_bitmap(panel_handle, x1, y1, x2 + 1, y2 + 1, oled_buffer);
+        ygg_i2c_lock_give();
+        if (err != ESP_OK) {
+            ESP_LOGW(TAG, "draw_bitmap failed: %s", esp_err_to_name(err));
+        }
+    } else {
+        ESP_LOGW(TAG, "I2C busy, skipping flush");
+    }
     lv_display_flush_ready(disp);
 }
 
@@ -71,7 +89,8 @@ void ygg_init_tick_cb() {
 }
 
 lv_display_t* ygg_sh1106_init() {
-    ESP_ERROR_CHECK(i2cdev_init());
+    // UWAGA: i2cdev_init() + ygg_lock_init() robi app_main() raz przed
+    // wszystkimi initami. Tutaj już nie tworzymy magistrali.
 
     static i2c_dev_t oled_i2c_dev;
     memset(&oled_i2c_dev, 0, sizeof(oled_i2c_dev));
@@ -102,6 +121,9 @@ lv_display_t* ygg_sh1106_init() {
     // Create the i2c io handle
     esp_lcd_panel_io_handle_t io_handle = NULL;
     esp_lcd_panel_io_i2c_config_t io_config = ESP_SH1106_DEFAULT_IO_CONFIG;
+    // Zejście z domyślnych 400kHz na 100kHz - wspólna magistrala z BMP280,
+    // pająk + słabe pull-upy. 400kHz/1MHz = timeouty.
+    io_config.scl_speed_hz = EXAMPLE_I2C_MASTER_FREQ_HZ;
     ESP_ERROR_CHECK(esp_lcd_new_panel_io_i2c(i2c_bus_handle, &io_config, &io_handle));
 
 
@@ -149,9 +171,16 @@ lv_display_t* ygg_sh1106_init() {
 }
 
 void ygg_set_display_label(lv_display_t *display, lv_obj_t *label, const char *str) {
+    // LVGL nie jest thread-safe. Ta funkcja jest wołana z sensor_task,
+    // a lv_timer_handler chodzi w lvgl_task - wszystko pod jednym mutexem.
+    if (!ygg_lvgl_lock_take(pdMS_TO_TICKS(500))) {
+        ESP_LOGW(TAG, "LVGL busy, skipping label update");
+        return;
+    }
     lv_label_set_text(label, str);
     /* Size of the screen (if you use rotation 90 or 270, please use lv_display_get_vertical_resolution) */
     lv_obj_set_width(label, lv_display_get_horizontal_resolution(display));
     lv_obj_set_style_text_align(label, LV_TEXT_ALIGN_CENTER, 0);
     lv_obj_align(label, LV_ALIGN_TOP_MID, 0, 0);
+    ygg_lvgl_lock_give();
 }