91 lines
3.0 KiB
Python
91 lines
3.0 KiB
Python
import gc
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import time
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from machine import Pin
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from pimoroni import Analog, AnalogMux, Button
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from plasma import WS2812
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from servo import ServoCluster, servo2040
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"""
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An example of how to use Servo 2040's current measuring
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ability and display the value on the onboard LED bar.
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Press "Boot" to exit the program.
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NOTE: ServoCluster and Plasma WS2812 use the RP2040's PIO system,
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and as such may have problems when running code multiple times.
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If you encounter issues, try resetting your board.
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"""
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BRIGHTNESS = 0.4 # The brightness of the LEDs
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UPDATES = 50 # How many times to update LEDs and Servos per second
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MAX_CURRENT = 3.0 # The maximum current, in amps, to show on the meter
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SAMPLES = 50 # The number of current measurements to take per reading
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TIME_BETWEEN = 0.001 # The time between each current measurement
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# Free up hardware resources ahead of creating a new ServoCluster
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gc.collect()
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# Create a servo cluster for pins 0 to 7, using PIO 0 and State Machine 0
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START_PIN = servo2040.SERVO_1
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END_PIN = servo2040.SERVO_8
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servos = ServoCluster(pio=0, sm=0, pins=list(range(START_PIN, END_PIN + 1)))
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# Set up the shared analog inputs
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cur_adc = Analog(servo2040.SHARED_ADC, servo2040.CURRENT_GAIN,
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servo2040.SHUNT_RESISTOR, servo2040.CURRENT_OFFSET)
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# Set up the analog multiplexer, including the pin for controlling pull-up/pull-down
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mux = AnalogMux(servo2040.ADC_ADDR_0, servo2040.ADC_ADDR_1, servo2040.ADC_ADDR_2,
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muxed_pin=Pin(servo2040.SHARED_ADC))
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# Create the LED bar, using PIO 1 and State Machine 0
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led_bar = WS2812(servo2040.NUM_LEDS, 1, 0, servo2040.LED_DATA)
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# Create the user button
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user_sw = Button(servo2040.USER_SW)
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# Start updating the LED bar
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led_bar.start()
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# Enable all servos (this puts them at the middle).
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# The servos are not going to be moved, but are activated to give a current draw
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servos.enable_all()
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# Read sensors until the user button is pressed
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while not user_sw.raw():
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# Select the current sense
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mux.select(servo2040.CURRENT_SENSE_ADDR)
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# Read the current sense several times and average the result
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current = 0
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for i in range(SAMPLES):
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current += cur_adc.read_current()
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time.sleep(TIME_BETWEEN)
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current /= SAMPLES
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# Print out the current sense value
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print("Current =", round(current, 4))
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# Convert the current to a percentage of the maximum we want to show
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percent = (current / MAX_CURRENT)
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# Update all the LEDs
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for i in range(servo2040.NUM_LEDS):
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# Calculate the LED's hue, with Red for high currents and Green for low
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hue = (1.0 - i / (servo2040.NUM_LEDS - 1)) * 0.333
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# Calculate the current level the LED represents
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level = (i + 0.5) / servo2040.NUM_LEDS
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# If the percent is above the level, light the LED, otherwise turn it off
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if percent >= level:
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led_bar.set_hsv(i, hue, 1.0, BRIGHTNESS)
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else:
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led_bar.set_hsv(i, hue, 1.0, 0.0)
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# Disable the servos
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servos.disable_all()
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# Turn off the LED bar
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led_bar.clear()
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