Initial commit

calibrate.py

@@ -0,0 +1,107 @@
+import time
+import ntptime
+import json
+import os
+from hx710b import HX710B    # Correct driver
+from config import *
+
+CALIB_FILE = "calibration.cfg"
+
+tz_offset = 0
+utc = time.localtime()
+local = time.localtime(time.mktime(utc) + tz_offset * 3600)
+ctime = f"{local[0]:02}-{local[1]:02}-{local[2]:02} {local[3]:02}:{local[4]:02}:{local[5]:02}"
+#print("Time =", local)
+print("Time =", ctime)
+
+# ---------------------------------------------------------
+# USER INPUT
+# ---------------------------------------------------------
+# Water depth (meters)
+# KNOWN_DEPTH_M = 1.680
+
+# Pressure created by water column (kPa)
+KNOWN_PRESSURE_KPA = KNOWN_DEPTH_M * 9.81
+
+print(
+    "\nUsing depth {:.3f} m → expected pressure {:.3f} kPa".format(
+        KNOWN_DEPTH_M, KNOWN_PRESSURE_KPA
+    )
+)
+
+# ---------------------------------------------------------
+# SAVE CALIBRATION
+# ---------------------------------------------------------
+def save_calibration(ctime, zero_offset, raw_at_pressure, scale_factor):
+    data = {
+        "zero_offset": zero_offset,
+        "raw_at_pressure": raw_at_pressure,        
+        "scale_factor": scale_factor,
+        "Date_Time": ctime
+    }
+
+    with open(CALIB_FILE, "w") as f:
+        json.dump(data, f)
+
+    print("\n✔ Saved calibration:")
+    print("   Date_Time       =", ctime)
+    print("   zero_offset     =", zero_offset)
+    print("   raw_at_pressure =", raw_at_pressure)
+    print("   scale_factor    =", scale_factor)
+
+
+# ---------------------------------------------------------
+# RAW AVERAGING
+# ---------------------------------------------------------
+def read_average(hx, samples=30):
+    total = 0
+    for _ in range(samples):
+        total += hx.read_raw()
+        time.sleep_ms(5)
+    return total / samples
+
+
+# ---------------------------------------------------------
+# CALIBRATION PROCESS
+# ---------------------------------------------------------
+print("\n=== HX710B Depth-Based Calibration ===")
+
+hx = HX710B(dout_pin=0, sck_pin=1)
+
+# Step 1 — ZERO PRESSURE
+print("\n➡ Ensure tank is OPEN TO AIR (0 kPa)...")
+time.sleep(3)
+
+zero_offset = read_average(hx)
+print("Zero offset captured:", zero_offset)
+
+# Step 2 — APPLY KNOWN PRESSURE
+print(
+    "\n➡ Now apply EXACTLY {:.3f} kPa (depth {:.3f} m)...".format(
+        KNOWN_PRESSURE_KPA, KNOWN_DEPTH_M
+    )
+)
+time.sleep(10)
+
+raw_at_pressure = read_average(hx)
+print("Raw at known depth:", raw_at_pressure)
+
+# Compute scale factor
+scale_factor = KNOWN_PRESSURE_KPA / (raw_at_pressure - zero_offset)
+
+# Save calibration (INCLUDING raw value)
+save_calibration(ctime, zero_offset, raw_at_pressure, scale_factor)
+
+print("\n=== Calibration Complete ===")
+
+# ---------------------------------------------------------
+# VERIFY
+# ---------------------------------------------------------
+hx.zero_offset = zero_offset
+hx.scale_factor = scale_factor
+
+test = hx.read_kpa()
+
+print("\nVerification reading:", test, "kPa")
+print("Expected:", KNOWN_PRESSURE_KPA, "kPa")
+print("\nDone.\n")