# This example shows how to read the voltage from a LiPo battery connected to a Raspberry Pi Pico via our Pico Lipo SHIM
# and uses this reading to calculate how much charge is left in the battery.
# It then displays the info on the screen of Pico Display.
# Remember to save this code as main.py on your Pico if you want it to run automatically!

from machine import ADC, Pin, I2C
import time
from sh1106 import SH1106_I2C

i2c = I2C(1, scl=27,sda=26)
oled = SH1106_I2C(128, 64, i2c)
oled.rotate(True)

vsys = ADC(29)                 # reads the system input voltage
charging = Pin(24 , Pin.IN)     # reading GP24 tells us whether or not USB power is connected
#plugged = Pin('WL_GPIO2', Pin.IN)
conversion_factor = 3 * 3.3 / 65535

full_battery = 4.3                 # these are our reference voltages for a full/empty battery, in volts
empty_battery = 3.0                # the values could vary by battery size/manufacturer so you might need to adjust them

while True:
    # convert the raw ADC read into a voltage, and then a percentage
    voltage = vsys.read_u16() * conversion_factor
    percentage = 100 * ((voltage - empty_battery) / (full_battery - empty_battery))

    if charging.value() == 1:
#    if plugged.value() == 1:         # if it's plugged into USB power...
        print("--- Charging! --")
        print('{:.2f}'.format(voltage) + "v")
        print('{:.0f}%'.format(percentage))
        oled.fill(0)
        oled.text("--- Charging! --", 0, 2)
        oled.hline(0, 12, 128, 10)
        oled.text("V: " + str(voltage), 5, 25)
        oled.text("%: " + str(percentage), 5, 35)       
        oled.show()
        time.sleep(2)

    else:                             # if not, display the battery stats
        print('{:.2f}'.format(voltage) + "v")
        print('{:.0f}%'.format(percentage))

        oled.fill(0)
        oled.text("V: " + str(voltage), 0, 10)
        oled.text("%: " + str(percentage), 0, 30)
        oled.show()

        time.sleep(2)