kopia lustrzana https://github.com/pimoroni/pimoroni-pico
82 wiersze
2.6 KiB
Python
82 wiersze
2.6 KiB
Python
# This example reads the voltage from a battery connected to Tufty 2040
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# and uses this reading to calculate how much charge is left in the battery.
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from picographics import PicoGraphics, DISPLAY_TUFTY_2040
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from machine import ADC, Pin
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import time
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display = PicoGraphics(display=DISPLAY_TUFTY_2040)
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display.set_backlight(0.8)
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# set up the ADCs for measuring battery voltage
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vbat_adc = ADC(29)
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vref_adc = ADC(28)
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vref_en = Pin(27)
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vref_en.init(Pin.OUT)
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vref_en.value(0)
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usb_power = Pin(24, Pin.IN) # reading GP24 tells us whether or not USB power is connected
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# Reference voltages for a full/empty battery, in volts
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# the values could vary by battery size/manufacturer so you might need to adjust them
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# Values for a Galleon 400mAh LiPo:
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full_battery = 3.7
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empty_battery = 2.5
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# set up some colours to draw with
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WHITE = display.create_pen(255, 255, 255)
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BLACK = display.create_pen(0, 0, 0)
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GREY = display.create_pen(190, 190, 190)
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GREEN = display.create_pen(0, 255, 0)
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RED = display.create_pen(255, 0, 0)
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display.set_font("bitmap8")
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while True:
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# The voltage reference on Tufty means we can measure battery voltage precisely, even when batteries are low.
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# Enable the onboard voltage reference
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vref_en.value(1)
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# Calculate the logic supply voltage, as will be lower that the usual 3.3V when running off low batteries
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vdd = 1.24 * (65535 / vref_adc.read_u16())
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vbat = (
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(vbat_adc.read_u16() / 65535) * 3 * vdd
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) # 3 in this is a gain, not rounding of 3.3V
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# Disable the onboard voltage reference
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vref_en.value(0)
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# Print out the voltage
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print("Battery Voltage = ", vbat, "V", sep="")
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# convert the raw ADC read into a voltage, and then a percentage
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percentage = 100 * ((vbat - empty_battery) / (full_battery - empty_battery))
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if percentage > 100:
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percentage = 100
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if percentage < 0:
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percentage = 0
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# draw the battery outline
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display.set_pen(BLACK)
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display.clear()
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display.set_pen(GREY)
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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(WHITE)
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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(GREEN)
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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(RED)
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if usb_power.value() == 1: # if it's plugged into USB power...
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display.text("USB power!", 15, 90, 240, 4)
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display.text('{:.2f}'.format(vbat) + "v", 15, 10, 240, 5)
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display.text('{:.0f}%'.format(percentage), 15, 50, 240, 5)
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display.update()
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time.sleep(0.5)
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