From fccf95c125e11032574b77c2cfcdfeaca4356485 Mon Sep 17 00:00:00 2001
From: thiswillbeyourgithub <github@32mail.33mail.comm>
Date: Wed, 16 Mar 2022 15:55:27 +0100
Subject: [PATCH] fix: smoothen battery voltage

Signed-off-by: thiswillbeyourgithub <github@32mail.33mail.comm>
---
 wasp/drivers/battery.py | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/wasp/drivers/battery.py b/wasp/drivers/battery.py
index e866920..e339fdc 100644
--- a/wasp/drivers/battery.py
+++ b/wasp/drivers/battery.py
@@ -26,6 +26,7 @@ class Battery(object):
         self._battery = ADC(battery)
         self._charging = charging
         self._power = power
+        self._cache = set()
 
     @micropython.native
     def charging(self):
@@ -33,7 +34,7 @@ class Battery(object):
 
         :returns: True if the battery is charging, False otherwise.
         """
-        return self._charging.value() 
+        return self._charging.value()
 
     def power(self):
         """Check whether the device has external power.
@@ -50,10 +51,21 @@ class Battery(object):
 
         Assumes a 50/50 voltage divider and a 3.3v power supply
 
+        The last values is kept in a cache and only the minium cached value is
+        shown to the user, this is to avoid the battery level
+        going up and down because of the lack of precision of the mv.
+        Note that this will underestimate battery level.
+
         :returns: Battery voltage, in millivolts.
         """
         raw = self._battery.read_u16()
-        return (2 * 3300 * raw) // 65535
+        mv = (2 * 3300 * raw) // 65535
+
+        if mv not in self._cache:
+            self._cache.add(mv)
+            while len(self._cache) > 2:
+                self._cache.remove(max(self._cache))
+        return min(self._cache)
 
     def level(self):
         """Estimate the battery level.
@@ -61,15 +73,12 @@ class Battery(object):
         The current the estimation approach is extremely simple. It is assumes
         the discharge from 4v to 3.5v is roughly linear and 4v is 100% and
         that 3.5v is 5%. Below 3.5v the voltage will start to drop pretty
-        sharply to we will drop from 5% to 0% pretty fast... but we'll
+        sharply so we will drop from 5% to 0% pretty fast... but we'll
         live with that for now.
 
         :returns: Estimate battery level in percent.
         """
         mv = self.voltage_mv()
         level = ((19 * mv) // 100) - 660
-        if level > 100:
-            return 100
-        if level < 0:
-            return 0
+        level = min(100, max(0, level))
         return level