Fix battery voltage scale and cleanup

ThomasFarstrike · ThomasFarstrike · commit 272989dc48fa · 2025-10-09T14:49:31.000+02:00
diff --git a/internal_filesystem/boot.py b/internal_filesystem/boot.py
@@ -82,6 +82,6 @@
 
 # Battery voltage ADC measuring
 import mpos.battery_voltage
-mpos.battery_voltage.init_adc(5)
+mpos.battery_voltage.init_adc(5, 262 / 100000)
 
 print("boot.py finished")
diff --git a/internal_filesystem/boot_fri3d-2024.py b/internal_filesystem/boot_fri3d-2024.py
@@ -214,6 +214,6 @@ def keypad_read_cb(indev, data):
 
 # Battery voltage ADC measuring
 import mpos.battery_voltage
-mpos.battery_voltage.init_adc(13)
+mpos.battery_voltage.init_adc(13, 2 / 1000)
 
 print("boot.py finished")
diff --git a/internal_filesystem/lib/mpos/battery_voltage.py b/internal_filesystem/lib/mpos/battery_voltage.py
@@ -1,72 +1,25 @@
+import time
+
+MIN_VOLTAGE = 3.15
+MAX_VOLTAGE = 4.15
+
 adc = None
-have_adc=True
+scale_factor = 0
 
 # This gets called by (the device-specific) boot*.py
-def init_adc(pinnr):
+def init_adc(pinnr, scale_factor):
     global adc
     try:
         from machine import ADC, Pin
-        print("setting adc")
+        print("Initializing ADC pin {pinnr} with scale_factor {scale_factor}")
         adc = ADC(Pin(pinnr))
-        print("adc set")
         # Set ADC to 11dB attenuation for 0–3.3V range (common for ESP32)
         adc.atten(ADC.ATTN_11DB)
     except Exception as e:
         print("Info: this platform has no ADC for measuring battery voltage")
-        have_adc=False
-
-import time
 
-# ADC parameters
-VREF = 3.3  # Reference voltage (3.3V for most boards, adjust if different)
-ADC_MAX = 4095  # 12-bit ADC resolution
-VOLTAGE_DIVIDER = 3  # (R1 + R2) / R2 = (200k + 100k) / 100k = 3
-
-MIN_VOLTAGE = 3.7
-MAX_VOLTAGE = 4.2
-
-# On fri3d-2024, it's 2367 for full
-# Battery voltage ranges from 3.15V (0%) to 4.15 (100%) as datasheet specifies
-# 3.0 +/- 0.1V (discharge cut-off) to 4.2V (no margin of error provided, assuming 0.05V)
-# Charger stops charging at 4.07V (92%) to reduce battery wear.
-#define RG_BATTERY_CALC_PERCENT(raw) (((raw) * 2.f - 3150.f) / (4150.f - 3150.f) * 100.f)
-#define RG_BATTERY_CALC_VOLTAGE(raw) ((raw) * 2.f * 0.001f)
-
-
-# USB connected, full battery: VBAT 4.179 5V: 5.1
-# read_battery_voltage raw_value: 1598.4
-# read_battery_voltage raw_value: 1598.1
-# read_battery_voltage raw_value: 1596.5
-# on display: 1596.8
-# => FULL is 1597 at 4.193V so * 2.6255 / 1000
-#
-# unplugged: VBAT: 4.157 5V: 0
-# 1591.3: 4.157		2.6123
-# 1588.5: 4.156
-# 1580.4: 4.14		2.619
-# 1577.8: 4.12
-# 1561.2: 4.08		2.61
-# 1555: 4.06
-# 1505: 3.95		2.624
-# 1489: 3.90
-# 1470: 3.85		2.61
-# 1454: 3.8
-# 1445: 3.81
-# 1412 should be empty 3.7
-#
-# USB connected, no battery:
-# 1566 * 0.00261 = 4.08V = 75%
-# 1566 * 0.00241 = 3.77V = 14%
-# 1564-1567
-#
-# quite empty and charging:
-# 1594: 4.18V
-# 16..
-#
-# logically, it should be * 0.00241758241758 but emperically, it seems to be * 0.00261 which is 8% higher
-# => Let's go with 0.00262
 def read_battery_voltage():
-    if not have_adc:
+    if not adc:
         import random
         random_voltage = random.randint(round(MIN_VOLTAGE*100),round(MAX_VOLTAGE*100)) / 100
         #print(f"returning random voltage: {random_voltage}")
@@ -79,23 +32,12 @@ def read_battery_voltage():
         total = total + adc.read()
     raw_value = total / 10
     #print(f"read_battery_voltage raw_value: {raw_value}")
-    # Convert to voltage, accounting for divider and reference
-    #voltage = (raw_value / ADC_MAX) * VREF * VOLTAGE_DIVIDER
-    #voltage = raw_value * 262 / 100000 # 2inch
-    voltage = raw_value * 2 / 1000 # fri3d-2024
+    voltage = raw_value * scale_factor
     # Clamp to 0–4.2V range for LiPo battery
     voltage = max(0, min(voltage, MAX_VOLTAGE))
-    #return raw_value
     return voltage
 
 # Could be interesting to keep a "rolling average" of the percentage so that it doesn't fluctuate too quickly
 def get_battery_percentage():
     return (read_battery_voltage() - MIN_VOLTAGE) * 100 / (MAX_VOLTAGE - MIN_VOLTAGE)
 
-
-# Main loop to read and print battery voltage
-if False:
-#for _ in range(10):
-    battery_voltage = read_battery_voltage()
-    print("Battery Voltage: {:.2f} V".format(battery_voltage))
-    time.sleep(1)  # Wait 1 second
diff --git a/internal_filesystem/lib/mpos/ui/topmenu.py b/internal_filesystem/lib/mpos/ui/topmenu.py
@@ -1,6 +1,8 @@
 import lvgl as lv
 
 import mpos.ui
+import mpos.battery_voltage
+
 from mpos.ui.anim import WidgetAnimator
 
 NOTIFICATION_BAR_HEIGHT=24
