62 lines
2.5 KiB
Python
62 lines
2.5 KiB
Python
# This example reads the voltage from a LiPo battery connected to Pimoroni Pico LiPo...
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# ...and uses this reading to calculate how much charge is left in the battery.
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# It then displays the info on the screen of Pico Display or Pico Explorer.
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# With Pimoroni Pico LiPo, you can read the battery percentage while it's charging.
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# Save this code as main.py on your Pico if you want it to run automatically!
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from machine import ADC, Pin
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import time
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# Uncomment one of these lines, depending on what display you have
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import picodisplay as display
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# import picodisplay2 as display
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# import picoexplorer as display
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# Set up and initialise display
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buf = bytearray(display.get_width() * display.get_height() * 2)
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display.init(buf)
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display.set_backlight(0.8) # comment out this line if you have a Pico Explorer, it doesn't have a controllable backlight
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vsys = ADC(29) # reads the system input voltage
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charging = Pin(24, Pin.IN) # reading GP24 tells us whether or not USB power is connected
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conversion_factor = 3 * 3.3 / 65535
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full_battery = 4.2 # reference voltages for a full/empty battery, in volts
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empty_battery = 2.8 # the values could vary by battery size/manufacturer so you might need to adjust them
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while True:
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# convert the raw ADC read into a voltage, and then a percentage
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voltage = vsys.read_u16() * conversion_factor
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percentage = 100 * ((voltage - empty_battery) / (full_battery - empty_battery))
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if percentage > 100:
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percentage = 100
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# draw the battery outline
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display.set_pen(0, 0, 0)
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display.clear()
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display.set_pen(190, 190, 190)
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display.rectangle(0, 0, 220, 135)
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display.rectangle(220, 40, 20, 55)
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display.set_pen(0, 0, 0)
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display.rectangle(3, 3, 214, 129)
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# draw a green box for the battery level
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display.set_pen(0, 255, 0)
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display.rectangle(5, 5, int((210 / 100) * percentage), 125)
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# add text
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display.set_pen(255, 0, 0)
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if charging.value() == 1: # if it's plugged into USB power...
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display.text("Charging!", 15, 90, 240, 4)
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display.text('{:.2f}'.format(voltage) + "v", 15, 10, 240, 5)
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display.text('{:.0f}%'.format(percentage), 15, 50, 240, 5)
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# uncomment for low battery alarm (Pico Explorer only, you'll need to have GP0 and AUDIO connected with a jumper wire)
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# display.set_audio_pin(0)
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# if percentage < 5: # if the battery is less than 5%
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# display.set_tone(262) # then make an annoying noise
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display.update()
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time.sleep(0.5)
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