98 lines
3.3 KiB
Python
98 lines
3.3 KiB
Python
import time
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from machine import RTC
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from pimoroni_i2c import PimoroniI2C
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from pimoroni import BREAKOUT_GARDEN_I2C_PINS # or PICO_EXPLORER_I2C_PINS or HEADER_I2C_PINS
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from breakout_encoder_wheel import BreakoutEncoderWheel, NUM_LEDS
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"""
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Displays a 12 hour clock on Encoder Wheel's LED ring, getting time from the system.
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Press Ctrl+C to stop the program.
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"""
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# Datetime Indices
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HOUR = 4
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MINUTE = 5
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SECOND = 6
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# Constants
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BRIGHTNESS = 1.0 # The brightness of the LEDs
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UPDATES = 50 # How many times the LEDs will be updated per second
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UPDATE_RATE_US = 1000000 // UPDATES
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# Handy values for the number of milliseconds
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MILLIS_PER_SECOND = 1000
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MILLIS_PER_MINUTE = MILLIS_PER_SECOND * 60
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MILLIS_PER_HOUR = MILLIS_PER_MINUTE * 60
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MILLIS_PER_HALF_DAY = MILLIS_PER_HOUR * 12
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# Create a new BreakoutEncoderWheel
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i2c = PimoroniI2C(**BREAKOUT_GARDEN_I2C_PINS)
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wheel = BreakoutEncoderWheel(i2c)
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# Access the built-in RTC
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rtc = RTC()
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# Sleep until a specific time in the future. Use this instead of time.sleep() to correct for
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# inconsistent timings when dealing with complex operations or external communication
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def sleep_until(end_time):
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time_to_sleep = time.ticks_diff(end_time, time.ticks_us())
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if time_to_sleep > 0:
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time.sleep_us(time_to_sleep)
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# Simple function to clamp a value between a minimum and maximum
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def clamp(n, smallest, largest):
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return max(smallest, min(n, largest))
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# Calculates the brightness of an LED based on its index and a position along the LED ring
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def led_brightness_at(led, position, half_width=1, span=1):
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brightness = 0.0
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upper = position + half_width
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lower = position - half_width
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if led > position:
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brightness = clamp((upper - led) / span, 0.0, 1.0)
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else:
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brightness = clamp((led - lower) / span, 0.0, 1.0)
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# Handle the LEDs being in a circle
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if upper >= NUM_LEDS:
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brightness = clamp(((upper - NUM_LEDS) - led) / span, brightness, 1.0)
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elif lower < 0.0:
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brightness = clamp((led - (lower + NUM_LEDS)) / span, brightness, 1.0)
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return int(brightness * BRIGHTNESS * 255)
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# Make rainbows
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while True:
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# Record the start time of this loop
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start_time = time.ticks_us()
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# Get the current system time
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now = rtc.datetime()
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# Convert the seconds, minutes, and hours into milliseconds (this is done to give a smoother animation, particularly for the seconds hand)
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sec_as_millis = (now[SECOND] * MILLIS_PER_SECOND)
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min_as_millis = (now[MINUTE] * MILLIS_PER_MINUTE) + sec_as_millis
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hour_as_millis = ((now[HOUR] % 12) * MILLIS_PER_HOUR) + min_as_millis
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# Calculate the position on the LED ring that the, second, minute, and hour hands should be
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sec_pos = min(sec_as_millis / MILLIS_PER_MINUTE, 1.0) * NUM_LEDS
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min_pos = min(min_as_millis / MILLIS_PER_HOUR, 1.0) * NUM_LEDS
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hour_pos = min(hour_as_millis / MILLIS_PER_HALF_DAY, 1.0) * NUM_LEDS
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for i in range(NUM_LEDS):
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# Turn on the LEDs close to the position of the current second, minute, and hour
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r = led_brightness_at(i, sec_pos)
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g = led_brightness_at(i, min_pos)
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b = led_brightness_at(i, hour_pos)
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wheel.set_rgb(i, r, g, b)
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wheel.show()
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# Sleep until the next update, accounting for how long the above operations took to perform
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sleep_until(time.ticks_add(start_time, UPDATE_RATE_US))
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