commit 1

lib/hx710b.py

@@ -0,0 +1,116 @@
+from machine import Pin
+import time
+import json
+import os
+
+CALIB_FILE = "calibration.cfg"
+
+
+# ---------------------------------------------------------
+# Calibration File Helpers
+# ---------------------------------------------------------
+
+def save_calibration(zero_offset, scale_factor):
+    """Save calibration values to internal flash."""
+    data = {
+        "zero_offset": zero_offset,
+        "scale_factor": scale_factor
+    }
+    with open(CALIB_FILE, "w") as f:
+        json.dump(data, f)
+    print("✔ Calibration saved.")
+
+
+def load_calibration():
+    """Load existing calibration or return defaults."""
+    if CALIB_FILE not in os.listdir():
+        print("⚠ No calibration file found, using defaults.")
+        return 0, 1
+
+    try:
+        with open(CALIB_FILE, "r") as f:
+            data = json.load(f)
+        print("✔ Calibration loaded.")
+        return data.get("zero_offset", 0), data.get("scale_factor", 1)
+    except Exception as e:
+        print("⚠ Calibration load error:", e)
+        return 0, 1
+
+
+# ---------------------------------------------------------
+# HX710B Class
+# ---------------------------------------------------------
+
+class HX710B:
+    def __init__(self, dout_pin, sck_pin):
+        self.dout = Pin(dout_pin, Pin.IN)
+        self.sck = Pin(sck_pin, Pin.OUT)
+        self.sck.value(0)
+
+        # Load previous calibration (or defaults)
+        self.zero_offset, self.scale_factor = load_calibration()
+
+    # -----------------------------------------------------
+    # Low-level raw ADC read
+    # -----------------------------------------------------
+    def read_raw(self):
+        """Read the 24-bit raw ADC value."""
+        while self.dout.value():
+            pass  # wait for data ready
+
+        count = 0
+        for _ in range(24):
+            self.sck.value(1)
+            count = (count << 1) | self.dout.value()
+            self.sck.value(0)
+
+        # 25th pulse to set gain for next reading
+        self.sck.value(1)
+        self.sck.value(0)
+
+        # Signed 24-bit conversion
+        if count & 0x800000:
+            count -= 0x1000000
+
+        return count
+
+    # -----------------------------------------------------
+    # Zero Calibration
+    # -----------------------------------------------------
+    def calibrate_zero(self, samples=20):
+        """Measure 0 kPa and determine zero offset."""
+        total = 0
+        for _ in range(samples):
+            total += self.read_raw()
+            time.sleep_ms(5)
+
+        self.zero_offset = total / samples
+        save_calibration(self.zero_offset, self.scale_factor)
+
+        print("✔ Zero calibrated:", self.zero_offset)
+        return self.zero_offset
+
+    # -----------------------------------------------------
+    # Full-scale / Known Pressure Calibration
+    # -----------------------------------------------------
+    def calibrate_full(self, known_kpa, samples=20):
+        """Measure raw ADC at known pressure and compute scaling."""
+        total = 0
+        for _ in range(samples):
+            total += self.read_raw()
+            time.sleep_ms(5)
+
+        raw_avg = total / samples
+        self.scale_factor = known_kpa / (raw_avg - self.zero_offset)
+
+        save_calibration(self.zero_offset, self.scale_factor)
+
+        print("✔ Scale calibrated:", self.scale_factor)
+        return self.scale_factor
+
+    # -----------------------------------------------------
+    # Convert raw → kPa using saved calibration
+    # -----------------------------------------------------
+    def read_kpa(self):
+        raw = self.read_raw()
+        return (raw - self.zero_offset) * self.scale_factor

lib/ssd1306.py

@@ -0,0 +1,89 @@
+# ssd1306.py
+# MicroPython SSD1306 OLED driver (I2C)
+# Compatible with 128x64 and 128x32 displays
+
+from machine import I2C, Pin
+import framebuf
+import time
+
+# SSD1306 commands
+SET_CONTRAST = 0x81
+DISPLAY_ALL_ON_RESUME = 0xA4
+DISPLAY_ALL_ON = 0xA5
+NORMAL_DISPLAY = 0xA6
+INVERT_DISPLAY = 0xA7
+DISPLAY_OFF = 0xAE
+DISPLAY_ON = 0xAF
+SET_DISPLAY_OFFSET = 0xD3
+SET_COM_PINS = 0xDA
+SET_VCOM_DETECT = 0xDB
+SET_DISPLAY_CLOCK_DIV = 0xD5
+SET_PRECHARGE = 0xD9
+SET_MULTIPLEX = 0xA8
+SET_LOW_COLUMN = 0x00
+SET_HIGH_COLUMN = 0x10
+SET_START_LINE = 0x40
+MEMORY_MODE = 0x20
+COLUMN_ADDR = 0x21
+PAGE_ADDR = 0x22
+COM_SCAN_INC = 0xC0
+COM_SCAN_DEC = 0xC8
+SEG_REMAP = 0xA0
+CHARGE_PUMP = 0x8D
+EXTERNAL_VCC = 0x1
+SWITCH_CAP_VCC = 0x2
+
+class SSD1306_I2C(framebuf.FrameBuffer):
+    def __init__(self, width, height, i2c, addr=0x3c):
+        self.width = width
+        self.height = height
+        self.i2c = i2c
+        self.addr = addr
+        self.pages = self.height // 8
+        self.buffer = bytearray(self.pages * self.width)
+        super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
+        self.init_display()
+
+    def write_cmd(self, cmd):
+        self.i2c.writeto(self.addr, bytearray([0x00, cmd]))
+
+    def init_display(self):
+        for cmd in (
+            DISPLAY_OFF,
+            SET_DISPLAY_CLOCK_DIV, 0x80,
+            SET_MULTIPLEX, self.height - 1,
+            SET_DISPLAY_OFFSET, 0x00,
+            SET_START_LINE | 0x00,
+            CHARGE_PUMP, 0x14,
+            MEMORY_MODE, 0x00,
+            SEG_REMAP | 0x1,
+            COM_SCAN_DEC,
+            SET_COM_PINS, 0x12 if self.height == 64 else 0x02,
+            SET_CONTRAST, 0xCF,
+            SET_PRECHARGE, 0xF1,
+            SET_VCOM_DETECT, 0x40,
+            DISPLAY_ALL_ON_RESUME,
+            NORMAL_DISPLAY,
+            DISPLAY_ON
+        ):
+            self.write_cmd(cmd)
+        self.fill(0)
+        self.show()
+
+    def show(self):
+        for page in range(self.pages):
+            self.write_cmd(0xB0 + page)
+            self.write_cmd(SET_LOW_COLUMN)
+            self.write_cmd(SET_HIGH_COLUMN)
+            start = self.width * page
+            end = start + self.width
+            self.i2c.writeto(self.addr, b'\x40' + self.buffer[start:end])
+
+    def poweroff(self):
+        self.write_cmd(DISPLAY_OFF)
+
+    def poweron(self):
+        self.write_cmd(DISPLAY_ON)
+
+    def invert(self, invert):
+        self.write_cmd(INVERT_DISPLAY if invert else NORMAL_DISPLAY)