openWB_OLEDDisplay

OpenWB status display using ESP8266 and 0.96" OLED Display. Displays current EVU (grid), PV and combined power of all charging ports plus SoC and status of up to the first two loadpoints (LP1 / LP2). The display automatically cycles between LP1 and LP2 if a second loadpoint is present.

Allows OTA updates via integrated WebBrowser on /update

Migration Note (HTTP Polling vs. MQTT)

This version replaces the previous MQTT subscription mechanism with periodic HTTP polling of a single configured host/endpoint. All power and status values are now parsed from a JSON payload returned by that HTTP endpoint.

Why the change?

• Simplifies setup (no MQTT broker credentials / topics required)
• Centralizes all data in one HTTP request
• Makes polling interval configurable (POLL_INTERVAL_MS)

What you need to configure now

In openWB_OLEDDisplay.ino near the top:

const char* HTTP_HOST = "192.168.10.140";   // openWB host/IP
const uint16_t HTTP_PORT = 80;               // Port (usually 80)
const char* HTTP_PATH = "/api/status";      // Path to JSON status
const unsigned long POLL_INTERVAL_MS = 5000; // Polling interval in ms

Adjust these to match your backend HTTP API. If your API path or JSON structure differs, adapt either HTTP_PATH (jq filter) or the parsing logic in parser.cpp (ParseEvccState).

Expected / Minimized JSON structure (EVCC example)

The sketch targets the evcc state endpoint with a jq filter that reduces the payload to only required fields for up to two loadpoints:

/api/state?jq={gridPower:.grid.power,pvPower:.pvPower,loadpoints:[.loadpoints[0],.loadpoints[1]]|map(select(.!=null)|{chargePower:.chargePower,soc:(.vehicleSoc//.soc),charging:.charging,plugged:(.connected//.plugged)})}

Resulting minimized JSON (example with two loadpoints):

{
  "gridPower": -1234,   // W (negative = export, positive = import)
  "pvPower": 3456,      // W PV generation
  "loadpoints": [
    {"chargePower": 2100, "soc": 78, "charging": true,  "plugged": true},
    {"chargePower":    0, "soc": 55, "charging": false, "plugged": true}
  ]
}

Field Mapping:

• gridPower -> EVU / Grid (import/export). Display shows absolute value; direction arrow uses sign.
• pvPower -> PV power (always treated as generation, absolute value shown).
• Sum of loadpoints[*].chargePower -> total charge power (LP_all_W).
• Each element of loadpoints (up to 2) -> internal loadpoint array (lps[0], lps[1]) with soc, charging, plugged.

If only one loadpoint exists, the array has a single entry and cycling is disabled automatically.

If your backend differs, adjust the jq filter in HTTP_PATH or extend the parsing logic in parser.cpp.

Library dependency

• ArduinoJson (install via Arduino Library Manager) for JSON parsing.

Legacy MQTT status endpoint

The built-in web endpoint / still works for health checks. The previous MQTT status handler now simply reports that MQTT is disabled.

Sketch assumes SPI Display, wiring for Wemos D1 & compatible:

• SCL: D1
• SDA: D2
• GND: GND
• VCC: 3.3V

Configuration

1. Enter your WiFi ssid and pass in the source file.
2. Update HTTP_HOST, HTTP_PATH, and optionally POLL_INTERVAL_MS.
3. Install ArduinoJson if not already available.
4. Optionally adjust LP_CYCLE_INTERVAL_MS (default 7000 ms) to change how fast the screen switches between LP1 and LP2 when two loadpoints are present.
5. Flash the sketch. First successful poll will update the display.

If you see only LP1, verify a second loadpoint is exposed by the backend and included by the jq filter.

If data does not appear, open the serial monitor (115200 baud) to inspect log lines for HTTP / JSON parse errors.

Runtime Log Zugriff über HTTP

Zusätzlich zur seriellen Ausgabe werden die letzten Log-Zeilen im RAM gepuffert und stehen unter folgenden Endpunkten zur Verfügung:

• /logs – Plain-Text Liste der letzten ca. 120 Zeilen (FIFO, älteste zuerst)
• /logs/clear – Puffer leeren (fügt danach eine Marker-Zeile <log cleared> ein)

Anpassung der Puffergröße über LOG_BUFFER_LINES und max. Zeilenlänge über LOG_MAX_LINE_LEN im Sketch.

Example

Graphic Symbols

Add #define UI_GRAPHIC_STYLE to change from text output to graphic output. There are symbols for energy import/export and charging status (unplugged | plugged | charging). Output is in Watt (W) if less than 1000 W and in kilo Watt (kW) if ≥ 1000 W. Above 10 kW it shows fewer decimal digits.

Examples for Graphic Symbols

Example plugged car

Example for charging car

Symbols: Import of energy

Export of energy

Unplugged

Plugged

Charging