Initial commit: Simple Sensor firmware for Heltec T114 with BME280

- MeshCore-based Simple Sensor firmware
- Heltec T114 without display
- BME280 sensor support (temp/humidity/pressure)
- Radio: 868.856018 MHz, SF7, BW62.5 kHz, CR4/7
- 2-byte path hash
- PlatformIO project

variants/ikoka_nano_nrf/IkokaNanoNRFBoard.h

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <MeshCore.h>
+#include <Arduino.h>
+#include <helpers/NRF52Board.h>
+
+#ifdef XIAO_NRF52
+
+class IkokaNanoNRFBoard : public NRF52BoardDCDC {
+public:
+  IkokaNanoNRFBoard() : NRF52Board("XIAO_NRF52_OTA") {}
+  void begin();
+
+#if defined(P_LORA_TX_LED)
+  void onBeforeTransmit() override {
+    digitalWrite(P_LORA_TX_LED, LOW);   // turn TX LED on
+    #if defined(LED_BLUE)
+       // turn off that annoying blue LED before transmitting
+       digitalWrite(LED_BLUE, HIGH);
+    #endif
+  }
+  void onAfterTransmit() override {
+    digitalWrite(P_LORA_TX_LED, HIGH);   // turn TX LED off
+    #if defined(LED_BLUE)
+       // do it after transmitting too, just in case
+       digitalWrite(LED_BLUE, HIGH);
+    #endif
+  }
+#endif
+
+  uint16_t getBattMilliVolts() override {
+    // Please read befor going further ;)
+    // https://wiki.seeedstudio.com/XIAO_BLE#q3-what-are-the-considerations-when-using-xiao-nrf52840-sense-for-battery-charging
+
+    // We can't drive VBAT_ENABLE to HIGH as long 
+    // as we don't know wether we are charging or not ...
+    // this is a 3mA loss (4/1500)
+    digitalWrite(VBAT_ENABLE, LOW);
+    int adcvalue = 0;
+    analogReadResolution(12);
+    analogReference(AR_INTERNAL_3_0);  
+    delay(10);
+    adcvalue = analogRead(PIN_VBAT);
+    return (adcvalue * ADC_MULTIPLIER * AREF_VOLTAGE) / 4.096;
+  }
+
+  const char *getManufacturerName() const override {
+    return MANUFACTURER_STRING;
+  }
+};
+
+#endif