Revise README for version 6.2.0 updates

Updated README for version 6.2.0, fixing DST handling and enhancing features.

CHANGELOG.md

@@ -4,116 +4,154 @@ All notable changes to this project are documented here.
 
 ---
 
+## v6.2.0 – DST (Daylight Saving Time) Handling Fixed (2026‑03‑29)
+
+**Summary**
+
+This release fixes a critical bug that caused incorrect price display on DST switch days. On March 29, 2026 (the spring forward day), the ticker at 12:41 showed prices for hours 13:00, 14:00, and 15:00 instead of the correct 12:00, 13:00, and 14:00.
+
+### Problem: Arithmetic-Based Index Calculation
+
+**Root Cause (v6.0.0 – v6.1.2):**
+
+The code assumed every day has exactly 96 price entries:
+
+```cpp
+int startIndex = hourIndex * 4;  // e.g., hour 12 → index 48
+```
+
+This assumption breaks on DST switch days:
+
+| Day Type | Hours | Price Entries | Example |
+|----------|-------|---------------|---------|
+| Normal day | 24 | 96 | Array indices 0-95 |
+| Spring forward (March) | 23 | 92 | Index 48 points to wrong time |
+| Fall back (October) | 25 | 100 | Index 48 points to wrong time |
+
+At 12:41 on March 29, 2026:
+- ESP32 correctly reported `timeinfo.tm_hour = 12`
+- Old code calculated `12 × 4 = 48`
+- But array only had 92 entries (no index 48 that maps to local hour 12)
+- Result: Displayed prices for 13:00, 14:00, 15:00 instead of 12:00, 13:00, 14:00
+
+### Solution: Timestamp-Based Lookups
+
+**New approach (v6.2.0):**
+
+All price lookups now search the `unix_seconds` array using actual timestamps:
+
+```cpp
+// Find index by searching for matching hour in timestamps
+int findPriceIndexForHour(const JsonArray& unixSeconds, int targetHour) {
+    for (size_t i = 0; i < unixSeconds.size(); i++) {
+        unsigned long unixTime = unixSeconds[i].as<unsigned long>();
+        time_t t = (time_t)unixTime;
+        struct tm* ptm = localtime(&t);
+        if (ptm != NULL && ptm->tm_hour == targetHour) {
+            return (int)i;  // Found correct index for this hour
+        }
+    }
+    return -1;
+}
+```
+
+**New functions added:**
+- `findPriceIndexForHour()` – Finds first price index for a given hour
+- `findCurrentPriceIndex()` – Finds current 15-minute slot using Unix timestamp
+- `getHourFromPriceIndex()` – Gets hour from price array index
+
+**Updated functions:**
+- `getHourlyAverage()` – Now uses timestamp lookup instead of `hourIndex * 4`
+- `display15MinuteDetails()` – Timestamp-based with hour verification in loop
+- `displayPriceRow()` – Timestamp-based data index lookup
+- `displayPrimaryList()` – Timestamp-based current hour detection
+- `updateLeds()` – Timestamp-based current interval lookup
+
+### Why This Is Future-Proof
+
+| Scenario | Code Behavior |
+|----------|--------------|
+| Normal days (96 entries) | Works as before |
+| DST spring forward (92 entries) | Timestamp lookup finds correct indices |
+| DST fall back (100 entries) | Timestamp lookup finds correct indices |
+| EU cancels DST | Only update `TZ_CET_CEST` string; code works unchanged |
+
+If EU parliament ever cancels DST switching, you only need to update the `TZ_CET_CEST` line (one line of code). The price lookup logic requires no changes.
+
+---
+
+## v6.1.2 – LED Indicator Restored (ESP32 PWM Fix) (2026‑03‑11)
+
+**Summary**
+
+This release fixes a regression introduced in **v6.1.1** where the **white LED price indicator** could remain **dimly lit** even when the LCD backlight turned off, and the intended **blink/breathe patterns** no longer behaved correctly.
+
+### Fixed: White LED Stuck Dim / Patterns Broken (PWM vs Digital)
+
+**Problem (v6.1.1):**
+
+- The sketch uses `analogWrite()` to drive the LED with PWM for breathe/blink patterns.
+- However, in some "LED OFF" branches the code used `digitalWrite(LOW)` on the same `whiteLedPin`.
+- On ESP32 (LEDC), once PWM is attached to a pin, `digitalWrite(LOW)` may **not fully disable** PWM output.
+- Result:
+  - LED could remain **faintly on** (dim glow) when LEDs were supposed to be off.
+  - Some patterns could appear "stuck" or inconsistent.
+
+**Solution (v6.1.2):**
+
+- LED control is now **PWM‑only** inside `updateLeds()`:
+  - Use `analogWrite(whiteLedPin, 0)` instead of `digitalWrite(whiteLedPin, LOW)`.
+  - Use `analogWrite(whiteLedPin, 255)` instead of `digitalWrite(whiteLedPin, HIGH)`.
+  - Blink/double‑blink toggles now switch between PWM **0** and **255**.
+- This ensures the LED is **truly off** whenever LED output is gated off.
+
+---
+
+## v6.1.1 – Daily Min/Max Includes Negative & Zero Prices (2026‑03‑07)
+
+**Summary**
+
+This release fixes a bug where the **daily lowest / highest hourly price marker** ignored negative prices (and also ignored 0.0), which could cause the ticker to incorrectly mark the **lowest positive** price as the daily minimum.
+
+### Fixed: Daily Low/High Marker Ignored Negative & Zero Prices
+
+**Problem (v6.1.0):**
+
+- In `processJsonData()` the daily min/max scan used:
+  ```cpp
+  if (hourlyAvg > 0) { ... }
+  ```
+- This had two side effects:
+  1. **Negative** hourly averages were completely skipped.
+  2. A true price of **0.0** was also skipped (even though 0 can be a valid market price).
+
+**Solution (v6.1.1):**
+
+- The min/max and average scan now:
+  - Treats an hour as valid based on **data availability** (having all 4×15‑minute entries), not based on value sign.
+  - Includes **all values** (negative, zero, positive).
+
+---
+
 ## v6.1.0 – Midnight Fetch & Market Day Fix (2026‑01‑30)
 
 **Summary**
 
-This release fixes a bug where the ticker could remain indefinitely on the **“No data for today”** screen after midnight, even though the API was already returning fresh data. It also refines the after‑midnight retry schedule.
+This release fixes a bug where the ticker could remain indefinitely on the **"No data for today"** screen after midnight, even though the API was already returning fresh data.
 
 ### Fixed: Stuck on NO_DATA_OFFSET After Midnight
 
 **Problem (v6.0.0):**
 
-- After midnight, the device:
-  - Detected day rollover and entered a “no data” state.
-  - Scheduled an immediate API fetch.
-- However:
-  - The API can continue to serve **yesterday’s market day** for some time after local midnight.
-  - The code only checked the **first** `unix_seconds` entry against the current local day.
-  - HTTP + JSON success always incremented `apiSuccessCount`, even if `processJsonData()` subsequently decided the dataset was “not for today”.
-  - The scheduler treated such fetches as **successful**, pushed `nextScheduledFetchTime` 24 hours into the future, and never retried.
-  - Result: the ticker stayed on **NO_DATA_OFFSET** forever, until:
-    - A manual long‑press triggered a fresh fetch at a time when the API finally returned recognized “today” data, or
-    - The device was rebooted later in the day.
+- The API can continue to serve **yesterday's market day** for some time after local midnight.
+- HTTP + JSON success always incremented `apiSuccessCount`, even if the data was "not for today".
+- The scheduler treated such fetches as **successful** and never retried.
 
 **Solution (v6.1.0):**
 
-1. **Market Day Detection**:
-   - `processJsonData()` now determines the “market day” using the **last** `unix_seconds` timestamp from the API’s dataset (assumed to cover one full day in 15‑minute steps).
-   - It compares that calendar date (local time) against the current local date.
-   - If they differ:
-     - The dataset is treated as **“not for today”**.
-     - `isTodayDataAvailable = false`.
-     - The function returns **false**, and a new flag `lastProcessJsonAcceptedToday` remains `false`.
-
-2. **Logical Failure vs HTTP/JSON Failure**:
-   - New global flag:
-     - `lastProcessJsonAcceptedToday` – `true` only when `processJsonData()` accepts the dataset as “today’s” data.
-   - In `handleDataFetching()`:
-     - A scheduled fetch is considered a **real success** only if:
-       - HTTP + JSON succeeded, **and**
-       - `lastProcessJsonAcceptedToday == true`.
-     - In all other cases (including “HTTP 200 + parse OK but data still for yesterday”):
-       - The fetch is treated as **failure** for scheduling purposes.
-       - If `midnightPhaseActive == true`, `scheduleAfterMidnightFailure()` is invoked to plan a retry.
-
-3. **Midnight Phase Cleanup**:
-   - When a fetch finally provides a dataset for today:
-     - `isTodayDataAvailable = true`.
-     - `lastProcessJsonAcceptedToday = true`.
-     - `midnightPhaseActive` is cleared; `midnightRetryCount` reset to 0.
-     - `nextScheduledFetchTime` is set to 24 hours ahead.
-
-As a result, the ticker will **keep retrying** after midnight until a correct market‑day dataset appears, instead of giving up after the first HTTP 200.
-
----
-
-### Changed: After‑Midnight Retry Schedule
-
-In `scheduleAfterMidnightFailure()` the retry strategy when `midnightPhaseActive == true` has been tuned.
-
-**Old behavior (v6.0.0, conceptual):**
-
-- First few failures after midnight:
-  - Retried every 10 minutes up to 5 attempts.
-- Afterwards:
-  - Switched to hourly retries (top of each hour).
-
-**New behavior (v6.1.0 + user configuration):**
-
-- Fast retry phase fully contained within the **first hour after midnight**.
-- You configured:
-
-  ```cpp
-  if (midnightRetryCount < 2) {
-      // Retry every 20 minutes for first 2 attempts (~1 hour window)
-      midnightRetryCount++;
-      nextScheduledFetchTime = now + 1200; // 20 minutes
-      debugPrint(2, "Midnight retry " + String(midnightRetryCount) + "/2 in 20 minutes");
-  } else {
-      // After that, retry only at top of each hour
-      ...
-  }
-  ```
-
-- Timeline:
-  - 00:00 – initial attempt (triggered by day rollover).
-  - If dataset is still for previous day:
-    - 1st retry at ~00:20.
-    - 2nd retry at ~00:40.
-  - After that:
-    - Retries only at the **top of the next hours** (01:00, 02:00, …),
-      until a dataset with market day = today is accepted.
-
-This configuration significantly reduces overnight API load while still ensuring the ticker picks up the new day as soon as the API publishes it.
-
----
-
-### Other Behavior (Retained From v6.0.0)
-
-- **NVS caching** of daily data:
-  - On boot, if NVS contains a dataset whose date matches today’s local date:
-    - The JSON is deserialized and processed.
-    - A new API call is **skipped**.
-  - After each accepted “today” fetch:
-    - Raw JSON payload, date, and a timestamp are stored in NVS.
-- **Manual long‑press refresh**:
-  - Still triggers immediate fetch via `nextScheduledFetchTime = now;`.
-  - Now also respects the improved “today” detection; “yesterday’s” data is not accepted as today.
-- **CET/CEST time handling**:
-  - Unchanged, still uses `TZ_CET_CEST` with `configTzTime`.
-- **Secondary menu and NVS status lines**:
-  - Retained from v6.0.0; updated only for version string and minor wording.
+- `processJsonData()` now determines the "market day" using the **last** `unix_seconds` timestamp.
+- A scheduled fetch is only successful if `lastProcessJsonAcceptedToday == true`.
+- Midnight retry logic keeps trying until valid "today" data is received.
 
 ---
 
@@ -125,30 +163,9 @@ First major redesign focused on reducing API traffic and improving resilience us
 
 ### New
 
-- NVS namespace `"my-ticker"` introduced with keys:
-  - `ssid`, `pass` – Wi‑Fi credentials.
-  - `data_day`, `data_mon`, `data_year` – stored data calendar day.
-  - `data_prc` – raw JSON string from API.
-  - `data_last_store` – Unix time when data was stored.
-- Boot behavior:
-  - Try to load and validate NVS data.
-  - If date matches today → reuse it and **skip** initial API call.
-- After‑midnight behavior:
-  - NVS is overwritten with each successful new‑day dataset.
-  - In‑RAM data for yesterday is invalidated at day rollover.
-
-### UI / Menu
-
-- Primary list:
-  - 15‑minute detail for current hour.
-  - Hourly averages for current + next 2 hours.
-- Secondary list:
-  - Expanded to 20 lines to include:
-    - Time/date, last update, daily average.
-    - Wi‑Fi RSSI, IP address.
-    - API success rate, uptime.
-    - NVS status block.
-    - Credits & version line.
+- NVS namespace `"my-ticker"` with Wi‑Fi credentials and daily price data caching.
+- Boot behavior: Try to load and validate NVS data; if date matches today → reuse it and **skip** initial API call.
+- After‑midnight: NVS is overwritten with each successful new‑day dataset.
 
 ---
 

HARDWARE_WIRING_DIAGRAM.md

@@ -0,0 +1,92 @@
+# Hardware Wiring Diagram (Seeed XIAO ESP32‑C3 Electricity Price Ticker)
+
+This document depicts the wiring for the **Electricity Price Ticker** project based on the connection instructions in `README.md`.
+
+It includes:
+- Required peripherals (LCD + button)
+- Supported optional peripherals (presence sensor + white LED + optional TTP223 touch button alternative)
+
+> Further reference (official board documentation):
+> - https://wiki.seeedstudio.com/XIAO_ESP32C3_Getting_Started/
+
+> Notes:
+> - Always connect **all grounds together** (ESP32 GND, LCD GND, sensor GND, LED GND).
+> - Verify your **XIAO ESP32‑C3 pinout** in the Seeed documentation link above.
+> - **Important:** The **10 kΩ pull-down resistor on D9 is mandatory at all times** (even if the presence sensor is not connected).
+> - Button input is on **D2**. You may use either a **mechanical pushbutton** (default) *or* a **TTP223 touch module** (alternative), but not both in parallel unless you know what you’re doing.
+
+---
+
+## 1) Wiring overview (diagram)
+
+```mermaid
+flowchart TB
+  MCU["Seeed XIAO ESP32-C3"]:::mcu
+
+  LCD["20x4 I2C LCD 2004<br/>PCF8574 backpack<br/>I2C addr 0x27"]:::lcd
+
+  %% Button input options (XIAO D2)
+  D2NODE["D2 node<br/>(buttonPin input)"]:::io
+  BTN["Mechanical pushbutton<br/>default option<br/>active LOW to GND"]:::btn
+  TTP["TTP223 capacitive touch<br/>optional alternative<br/>OUT is HIGH when touched"]:::touch
+
+  %% Presence-sensor input stage (XIAO D9) - always present
+  D9NODE["D9 node<br/>(presencePin input)"]:::io
+  RPD["10k pull-down resistor<br/>D9 to GND<br/>MANDATORY"]:::res
+  PRES["RCWL-0516 presence sensor<br/>optional"]:::pres
+
+  %% White LED output (XIAO D3)
+  LED1["White indicator LED<br/>optional"]:::led
+
+  PSU5V["5V supply<br/>USB-C or regulated 5V"]:::pwr
+  V33["3.3V rail from XIAO"]:::pwr
+  GND["Common GND"]:::gnd
+
+  %% Power
+  PSU5V -->|"5V"| MCU
+  PSU5V -->|"5V or 3V3 if LCD supports"| LCD
+  MCU -->|"3V3"| V33
+  V33 -->|"3V3"| PRES
+  V33 -->|"3V3"| TTP
+
+  %% Grounds
+  MCU --- GND
+  LCD --- GND
+  BTN --- GND
+  TTP --- GND
+  D2NODE --- GND
+
+  D9NODE --- GND
+  PRES --- GND
+
+  LED1 --- GND
+  PSU5V --- GND
+
+  %% I2C
+  MCU -->|"SDA D4"| LCD
+  MCU -->|"SCL D5"| LCD
+
+  %% Button input stage (always)
+  MCU -->|"D2 (buttonPin)"| D2NODE
+  BTN -->|"button to GND"| D2NODE
+  TTP -->|"OUT to D2 node"| D2NODE
+
+  %% Presence input stage (always)
+  MCU -->|"D9 (presencePin)"| D9NODE
+  D9NODE ---|"10k"| RPD
+  RPD -->|"to GND"| GND
+  PRES -->|"OUT to D9 node"| D9NODE
+
+  %% White LED (single LED, directly from pin with series resistor)
+  MCU -->|"D3 (whiteLedPin)"| LED1
+
+classDef mcu fill:#e8f0ff,stroke:#2b5fd9,stroke-width:1px,color:#000;
+classDef lcd fill:#fff4e5,stroke:#cc7a00,stroke-width:1px,color:#000;
+classDef btn fill:#eaffea,stroke:#2d8a2d,stroke-width:1px,color:#000;
+classDef touch fill:#e6fcff,stroke:#0077b6,stroke-width:1px,color:#000;
+classDef pres fill:#f3e8ff,stroke:#7b2cbf,stroke-width:1px,color:#000;
+classDef led fill:#ffe8ef,stroke:#c9184a,stroke-width:1px,color:#000;
+classDef res fill:#f5f5f5,stroke:#444,stroke-width:1px,color:#000;
+classDef pwr fill:#fff,stroke:#444,stroke-width:1px,color:#000;
+classDef gnd fill:#fff,stroke:#000,stroke-width:1.5px,color:#000;
+classDef io fill:#f5f5f5,stroke:#111,stroke-width:1px,color:#000;

README.md

@@ -1,3 +1,5 @@
+![Standalone ESP32 Electricity Price Ticker](device_photo.jpg)
+
 # Electricity Price Ticker for XIAO ESP32‑C3 (Energy‑Charts)
 
 This project is an Arduino‑IDE‑friendly firmware for the **Seeed XIAO ESP32‑C3** that:
@@ -9,16 +11,61 @@ This project is an Arduino‑IDE‑friendly firmware for the **Seeed XIAO ESP32
 - Uses a white LED and an optional presence sensor to give quick visual feedback.
 - Stores daily price data in **NVS** to survive reboots and reduce API calls.
 
-The latest sketch implements **Version 6.1.0**, focusing on:
+The latest sketch implements **Version 6.2.0**, focusing on:
 
+- **Version 6.2.0 FIX**: **DST (Daylight Saving Time) handling fully fixed** – the ticker now works correctly on ALL days including DST switch days (spring forward and fall back). Uses timestamp-based price lookups instead of arithmetic calculations.
+- Version 6.1.2 fix: restore correct **white LED indicator** behavior (ESP32 PWM fix; no dim glow when off).
+- Version 6.1.1 fix: Correct daily **low/high hourly markers** (now includes negative and **0.0** prices).
 - Daily (not hourly) API fetching.
 - Robust **NVS storage** of daily price data.
 - Correct **CET/CEST** handling.
-- Resilient **after‑midnight refresh** (no more getting stuck on “No data for today”).
+- Resilient **after‑midnight refresh** (no more getting stuck on "No data for today").
 - Preserved UI and button behavior from v5.5.
 
 ---
 
+## DST (Daylight Saving Time) – How It Works
+
+### v6.2.0: Fully DST-Safe
+
+**Important**: Starting with v6.2.0, the ticker is **fully DST-safe** and requires **no manual intervention** on DST switch days.
+
+The firmware uses **timestamp-based price lookups** that work correctly regardless of whether the day has 23, 24, or 25 hours:
+
+| Day Type | Hours in Day | Price Entries | Status |
+|----------|-------------|---------------|--------|
+| Normal | 24 | 96 | ✅ Works |
+| Spring forward (March) | 23 | 92 | ✅ Works (fixed in v6.2.0) |
+| Fall back (October) | 25 | 100 | ✅ Works (fixed in v6.2.0) |
+
+### Timezone Configuration
+
+The firmware uses the `TZ_CET_CEST` timezone string for displaying local time:
+
+```cpp
+const char* TZ_CET_CEST = "CET-1CEST,M3.5.0/02:00,M10.5.0/03:00";
+```
+
+**Current behavior:**
+- Spring forward: Last Sunday of March at 02:00 → 03:00 (CEST, UTC+2)
+- Fall back: Last Sunday of October at 03:00 → 02:00 (CET, UTC+1)
+
+### Future-Proof: If EU Cancels DST
+
+If the EU parliament ever cancels DST switching, you only need to update **one line of code**:
+
+```cpp
+// Option A - Stay on CET (UTC+1, winter time) permanently:
+const char* TZ_CET_CEST = "CET-1";
+
+// Option B - Stay on CEST (UTC+2, summer time) permanently:
+const char* TZ_CET_CEST = "CEST-2";
+```
+
+The rest of the code works unchanged because it uses timestamp-based lookups.
+
+---
+
 ## Bidding Zones (BZN) / Region Selection
 
 The firmware currently uses:
@@ -114,11 +161,12 @@ Typical pins used in the sketch:
 
 **Connections:**
 
-- **LCD backpack → XIAO ESP32‑C3**
-  - `VCC` → **5V** (or 3V3 if your module explicitly supports 3.3V I²C)
-  - `GND` → **GND**
-  - `SDA` → board I²C SDA pin (see XIAO ESP32‑C3 documentation)
-  - `SCL` → board I²C SCL pin
+| LCD Backpack | XIAO ESP32‑C3 |
+|-------------|---------------|
+| VCC | 5V |
+| GND | GND |
+| SDA | I²C SDA |
+| SCL | I²C SCL |
 
 > Note: On many XIAO ESP32‑C3 board definitions, SDA/SCL are mapped internally. Just use the default I²C pins as documented by Seeed.
 
@@ -183,12 +231,14 @@ The presence sensor is used to control LCD backlight and LEDs to save power and
 
 Recommended module: **RCWL‑0516** microwave motion sensor.
 
-**Wiring (from the v5.5 header, preserved in v6.x):**
+**Wiring:**
 
-- `VCC` → **3.3V**
-- `GND` → **GND**
-- `OUT` → `GPIO 9` (`presencePin`)
-- **Required**: 10 kΩ pull‑down resistor between `GPIO 9` and `GND`.
+| RCWL‑0516 | Connection |
+|-----------|------------|
+| VCC | 3.3V |
+| GND | GND |
+| OUT | GPIO 9 (`presencePin`) |
+| **Required**: 10kΩ pull‑down | Between GPIO 9 and GND |
 
 Characteristics:
 
@@ -236,23 +286,16 @@ The LED is driven with various patterns to indicate price level; see “LED Pric
 
 ---
 
-## Firmware Features (v6.1.0)
+## Firmware Features (v6.2.0)
 
 ### Core Display & Pricing
 
-- Data source:
-
-  ```text
-  https://api.energy-charts.info/price?bzn=SI
-  ```
-
-- Resolution:
-  - Prices in **15‑minute intervals** (`price[]`, `unix_seconds[]`).
-  - Display shows:
-    - **Row 0**: Current hour, four 15‑minute values in compact format (`XX XX XX XX`).
-    - **Rows 1–3**: Current hour + next two hours as hourly averages.
-- Price calculation:
-  - Raw MWh prices are converted to **EUR/kWh**.
+- Data source: `https://api.energy-charts.info/price?bzn=SI`
+- Resolution: 15‑minute intervals with hourly averages
+- Display shows:
+  - **Row 0**: Current hour, four 15‑minute values
+  - **Rows 1–3**: Current hour + next two hours as hourly averages
+- Price calculation: Raw MWh → EUR/kWh with configurable surcharges (power company fee + VAT)
   - Two configurable surcharges:
     - `POWER_COMPANY_FEE_PERCENTAGE` (default `12.0` %).
     - `VAT_PERCENTAGE` (default `22.0` %).
@@ -260,17 +303,27 @@ The LED is driven with various patterns to indicate price level; see “LED Pric
   - `LiquidCrystal_I2C` with custom characters for:
     - Local language letters.
     - Low‑price and high‑price indicators.
+- **Daily min/max markers**:
+  - The low/high hourly indicators consider **negative**, **0.0**, and positive prices (v6.1.1 fix).
 
 ### LED Price Signalling
 
 The white LED (GPIO 5) reflects the **current 15‑minute interval** price:
 
-- Very cheap (`<= 0.05 EUR/kWh`) → smooth breathing.
-- Cheap / normal → steady on.
-- Moderately expensive → slow blink.
-- Expensive → faster blink.
-- Very expensive → complex “double‑blink with long on” pattern.
-- Negative price or no data → LED off.
+| Price Level | LED Behavior |
+|-------------|--------------|
+| Negative / no data | LED off |
+| ≤ 0.05 EUR/kWh | Smooth breathing |
+| 0.05 – 0.15 | Steady on |
+| 0.15 – 0.25 | Slow blink |
+| 0.25 – 0.35 | Fast blink |
+| 0.35 – 0.50 | Double blink |
+| > 0.50 | Triple blink pattern |
+
+**Important implementation note (from v6.1.2 on):**
+
+- On ESP32, avoid mixing PWM (`analogWrite`) and `digitalWrite` on the same LED pin.
+- The firmware now uses `analogWrite(pin, 0/255)` consistently to guarantee the LED is fully off when gated off.
 
 LED is **disabled** when:
 
@@ -349,7 +402,7 @@ After successful NTP time sync:
 
 ---
 
-## Daily Fetch Strategy (v6.1.0)
+## Daily Fetch Strategy (v6.1.0+)
 
 ### Goals
 
@@ -542,7 +595,7 @@ If NVS does not contain valid Wi‑Fi credentials, or if connecting fails repeat
    - `DNSServer` (from ESP32 core)
    - `WebServer` (from ESP32 core)
    - `Preferences` (built‑in for ESP32)
-3. Open the v6.1 `.ino` file (e.g. `20260130_electricity_ticker_6_1_nvs_daily_fetch.ino`).
+3. Open the v6.2.0 `.ino` file (e.g. `ESP32_standalone_electricity_ticker_6_1_2_nvs_daily_fetch.ino`).
 4. In Tools:
    - Board: `Seeed XIAO ESP32C3`
    - Port: choose the correct serial port.
@@ -555,13 +608,15 @@ If NVS does not contain valid Wi‑Fi credentials, or if connecting fails repeat
 
 ---
 
+
 ## Versioning & Changelog
 
-- **v5.5** – 15‑minute detail mode, LED based on current 15‑minute slot, improved DST handling (see file `20251027a_electricity_ticker_10_5_5_latest_DST_and_midnight_fix.ino`).
-- **v6.0.0** – First NVS‑enabled version:
-  - Store daily price data in NVS.
-  - Reduce API calls to “boot + after‑midnight”.
-  - Add NVS status section to secondary menu.
+- **v6.2.0** – DST handling fully fixed via timestamp-based lookups
+- **v6.1.2** – LED indicator restored (broken in previous version):
+  - Avoid mixing PWM and `digitalWrite` on the same LED pin (ESP32 LEDC behavior).
+  - Ensures LED is fully off when gated off; patterns operate correctly.
+- **v6.1.1** – Daily low/high marker fix:
+  - Daily min/max and average now include negative and **0.0** prices.
 - **v6.1.0** – Midnight fetch & “today” detection fixes:
   - Correctly detect **market day** using the last `unix_seconds` timestamp.
   - Distinguish between:
@@ -571,6 +626,11 @@ If NVS does not contain valid Wi‑Fi credentials, or if connecting fails repeat
     - Two retries every 20 minutes in the first hour (~00:20, ~00:40).
     - Then hourly retries (top‑of‑hour) until today’s dataset is available.
   - Behavior on reboot and manual long‑press is unchanged, but now respects the improved “today” logic.
+- **v6.0.0** – NVS storage & daily fetch:
+  - Store daily price data in NVS.
+  - Reduce API calls to “boot + after‑midnight”.
+  - Add NVS status section to secondary menu.
+- **v5.5** – 15‑minute detail mode, LED based on current 15‑minute slot, improved DST handling (see file `20251027a_electricity_ticker_10_5_5_latest_DST_and_midnight_fix.ino`).
 
 See [`CHANGELOG.md`](./CHANGELOG.md) for more details.
 

VERSION.md

@@ -2,25 +2,45 @@
 
 ## Current firmware
 
-- **Version:** 6.0.0  
-- **Release date:** 2026-01-27  
-- **Target MCU:** Seeed XIAO ESP32‑C3  
-- **Display:** 20x4 I²C LCD (PCF8574, default address `0x27`)  
-- **API endpoint:** `https://api.energy-charts.info/price?bzn=SI`  
-- **Resolution:** 15‑minute intervals, hourly averages for overview  
+- **Version:** 6.2.0
+- **Release date:** 2026-03-29
+- **Target MCU:** Seeed XIAO ESP32‑C3
+- **Display:** 20x4 I²C LCD (PCF8574, default address `0x27`)
+- **API endpoint:** `https://api.energy-charts.info/price?bzn=SI`
+- **Resolution:** 15‑minute intervals, hourly averages for overview
 
-## Highlights of v6.0.0
+## Highlights of v6.2.0
 
-- Single **daily fetch** (on boot / after midnight) instead of hourly.
-- **NVS storage** of daily data for resilience to power outages.
-- Robust midnight rollover and retry logic:
-  - First immediate fetch.
-  - Up to 5 × 10‑minute retries.
-  - Then top‑of‑hour retries until successful.
-- Prevents yesterday’s prices from ever being shown as today’s.
-- Secondary info menu extended with **NVS status** and clear version label.
+- **CRITICAL FIX**: DST (Daylight Saving Time) handling is now fully fixed for all days.
+- Previously, the code assumed every day has exactly 96 price entries (24h × 4). This caused incorrect price display on DST switch days:
+  - Spring forward (March): Only 92 entries → wrong prices displayed
+  - Fall back (October): 100 entries → wrong prices displayed
+- **Solution**: All price lookups now use timestamp-based searching through the `unix_seconds` array instead of arithmetic calculation (`hourIndex * 4`).
+- New functions: `findPriceIndexForHour()`, `findCurrentPriceIndex()`, `getHourFromPriceIndex()`
+- Updated functions: `getHourlyAverage()`, `display15MinuteDetails()`, `displayPriceRow()`, `displayPrimaryList()`, `updateLeds()`
+- The ticker now works correctly on all days, including DST switch days, with no manual intervention.
+- **Future-proof**: If EU cancels DST, only the `TZ_CET_CEST` string needs updating (one line of code).
 
 For full details, see:
 
 - [CHANGELOG.md](./CHANGELOG.md)
 - [README.md](./README.md)
+
+## Previous firmware
+
+- **Version:** 6.1.2
+- **Release date:** 2026-03-11
+- **Target MCU:** Seeed XIAO ESP32‑C3
+
+## Highlights of v6.1.2
+
+- Fix: restore proper white LED price indicator behavior on ESP32 by avoiding mixing PWM (`analogWrite`) and `digitalWrite` on the same pin.
+- Fix: LED is now truly off when backlight/LED gating turns it off (no more "dim glow").
+
+## Earlier firmware
+
+- **Version:** 6.1.1 (2026-03-07) – Daily low/high marker includes negative and zero prices
+- **Version:** 6.1.0 (2026-01-30) – Midnight fetch and market day detection fixes
+- **Version:** 6.0.0 (2026-01-27) – NVS storage and daily fetch
+
+For detailed history, see [CHANGELOG.md](./CHANGELOG.md).