65 lines
2.4 KiB
Python
65 lines
2.4 KiB
Python
# This example reads the voltage from a LiPo battery connected to Pimoroni Pico LiPo
|
|
# and uses this reading to calculate how much charge is left in the battery.
|
|
# It then displays the info on the screen of Pico Explorer.
|
|
# With Pimoroni Pico LiPo, you can read the battery percentage while it's charging.
|
|
# Save this code as main.py on your Pico if you want it to run automatically!
|
|
|
|
from machine import ADC, Pin
|
|
import time
|
|
from pimoroni import Buzzer
|
|
from picographics import PicoGraphics, DISPLAY_PICO_EXPLORER
|
|
|
|
display = PicoGraphics(display=DISPLAY_PICO_EXPLORER)
|
|
|
|
buzzer = Buzzer(0)
|
|
|
|
vsys = ADC(29) # reads the system input voltage
|
|
charging = Pin(24, Pin.IN) # reading GP24 tells us whether or not USB power is connected
|
|
conversion_factor = 3 * 3.3 / 65535
|
|
|
|
full_battery = 4.2 # reference voltages for a full/empty battery, in volts
|
|
empty_battery = 2.8 # the values could vary by battery size/manufacturer so you might need to adjust them
|
|
|
|
# Create some pen colours for drawing with
|
|
BLACK = display.create_pen(0, 0, 0)
|
|
GREY = display.create_pen(190, 190, 190)
|
|
GREEN = display.create_pen(0, 255, 0)
|
|
RED = display.create_pen(255, 0, 0)
|
|
|
|
while True:
|
|
buzzer.set_tone(0)
|
|
|
|
# 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 percentage > 100:
|
|
percentage = 100
|
|
|
|
# draw the battery outline
|
|
display.set_pen(BLACK)
|
|
display.clear()
|
|
display.set_pen(GREY)
|
|
display.rectangle(0, 0, 220, 135)
|
|
display.rectangle(220, 40, 20, 55)
|
|
display.set_pen(BLACK)
|
|
display.rectangle(3, 3, 214, 129)
|
|
|
|
# draw a green box for the battery level
|
|
display.set_pen(GREEN)
|
|
display.rectangle(5, 5, int((210 / 100) * percentage), 125)
|
|
|
|
# add text
|
|
display.set_pen(RED)
|
|
if charging.value() == 1: # if it's plugged into USB power...
|
|
display.text("Charging!", 15, 90, 240, 4)
|
|
|
|
display.text('{:.2f}'.format(voltage) + "v", 15, 10, 240, 5)
|
|
display.text('{:.0f}%'.format(percentage), 15, 50, 240, 5)
|
|
|
|
# Low battery alarm! (you'll need to have GP0 and AUDIO connected with a jumper wire)
|
|
if percentage < 5: # if the battery is less than 5%
|
|
buzzer.set_tone(262) # then make an annoying noise
|
|
|
|
display.update()
|
|
time.sleep(0.5)
|