Create README.md

soilProbeNode/README.md

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+<br/>
+<div align="center">
+<a href="https://github.com/programmingPug/plantpal">
+<img src="https://imgur.com/BdczfrQ.png" alt="Logo" width="80" height="80">
+</a>
+<h3 align="center">PlantPal</h3>
+<p align="center">
+Because knowing when to water your plants is hard
+</p>
+</div>
+
+## Probe node's features
+
+### Battery Monitoring:
+
+- The probe node reads the battery voltage from the analog input (A0) using 10 samples and calculates an average.
+- Using a resistor divider (220 kΩ resistors) and known voltage parameters, it converts the ADC reading into an estimated battery voltage.
+- The voltage is then mapped to a percentage (for a typical 3.7V LiPo, for example, with 4.2 V as 100% and 3.0 V as 0%) so that you always know the current battery state.
+
+### Soil Moisture Sensing:
+
+- The sensor on A3 is read using 20 samples spaced 0.1 seconds apart. This creates an average raw reading that is then mapped into a moisture percentage.
+- Calibration values (dry and wet) are used to translate the raw sensor value into a meaningful moisture percentage.
+
+### Calibration Mode:
+
+- A physical button on D1 is used to trigger calibration.
+1) First press: Enters dry calibration mode. After a 10‑second delay, the device takes 20 samples and averages them to determine the "dry" value.
+2) Second press: Enters wet calibration mode with the same process to record the "wet" value.
+3) Third press: Finalizes calibration, saves the new calibration values to EEPROM, and exits calibration mode.
+- If no user calibration has been performed (or if no valid calibration is present in EEPROM), the node falls back on predefined default calibration values so that it is still usable.
+
+### BLE Server & Advertising:
+
+- The probe node sets up a BLE server using the predefined service and characteristic UUIDs.
+- It advertises its data (both soil moisture and battery percentage) as BLE characteristics so that a reporter node can connect, read, and process the data.
+- The BLE characteristics are updated periodically with the latest sensor readings and notify connected clients.
+
+### Deep Sleep for Energy Efficiency:
+
+- For battery-powered operation, once data is reported (or if the device has been awake for a set period), the probe node enters deep sleep (for example, 6 hours). This helps to conserve battery life, yet the device can be woken up—by a button press—for calibration or other interactions.
+
+### Overall Integration:
+
+- The node uses EEPROM to store calibration data so that values persist across power cycles.
+- The code is structured to average multiple readings (to avoid outliers) and uses delay intervals that ensure stable sensor data.
+- Debug output via Serial is available (and can be disabled for production) to assist during development and troubleshooting.