Merge pull request #2241 from adafruit/TheKitty-patch-1

Files for the Clue Coffee Scale Guide

Clue_Scale/README.md

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+Files for the ADafruit Learning System guide Clue Coffee Scale
+https://learn.adafruit.com/clue-coffee-scale/overview

Clue_Scale/clue_scale_calibrator.py

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+# SPDX-FileCopyrightText: 2022 Jan Goolsbey for Adafruit Industries
+# SPDX-License-Identifier: MIT
+#
+# clue_scale_calibrator.py
+# 2022-07-29 v1.1.0
+#
+# Clue Scale Calibrator - Single Channel Version
+# Adafruit NAU7802 Stemma breakout example
+
+import time
+import board
+from adafruit_clue import clue
+from cedargrove_nau7802 import NAU7802
+
+clue.pixel.brightness = 0.2  # Set NeoPixel brightness
+clue.pixel[0] = clue.YELLOW  # Set status indicator to yellow (initializing)
+
+SAMPLE_AVG = 500  # Number of sample values to average
+DEFAULT_GAIN = 128  # Default gain for internal PGA
+
+# Instantiate 24-bit load sensor ADC
+nau7802 = NAU7802(board.I2C(), address=0x2A, active_channels=1)
+
+
+def zero_channel():
+    """Initiate internal calibration and zero the current channel. Use after
+    power-up, a new channel is selected, or to adjust for measurement drift.
+    Can be used to zero the scale with a tare weight."""
+    nau7802.calibrate("INTERNAL")
+    nau7802.calibrate("OFFSET")
+
+
+def read(samples=100):
+    # Read and average consecutive raw sample values; return average raw value
+    sample_sum = 0
+    sample_count = samples
+    while sample_count > 0:
+        if nau7802.available:
+            sample_sum = sample_sum + nau7802.read()
+            sample_count -= 1
+    return int(sample_sum / samples)
+
+
+# Activate the NAU780 internal analog circuitry, set gain, and calibrate/zero
+nau7802.enable(True)
+nau7802.gain = DEFAULT_GAIN  # Use default gain
+zero_channel()  # Calibrate and zero
+
+print("-----------------------------------")
+print(" NAU7802 SINGLE CHANNEL CALIBRATOR")
+print("-----------------------------------")
+print("Place a calibration weight on the")
+print("load cell.")
+print("To re-zero the load cell, remove")
+print("any weights then press and hold A.")
+print("-----------------------------------")
+print("")
+
+# Play "welcome" tones
+clue.play_tone(1660, 0.15)
+clue.play_tone(1440, 0.15)
+
+# Main loop: Read sample and display value
+while True:
+    clue.pixel[0] = clue.GREEN  # Set status indicator to green
+
+    # Read the raw value; print raw value, gain setting, and % of full-scale
+    value = read(SAMPLE_AVG)
+    print(f"CHAN_{nau7802.channel:1.0f} RAW VALUE: {value:7.0f}")
+    print(f"GAIN: x{DEFAULT_GAIN}  full-scale: {(value / ((2**23) - 1)) * 100:3.2f}%")
+    print("===================================")
+
+    time.sleep(0.1)
+
+    if clue.button_a:
+        # Zero and recalibrate the NAU780
+        clue.play_tone(1660, 0.3)  # Play "button pressed" tone
+        clue.pixel[0] = clue.RED  # Set status indicator to red (stopped)
+        zero_channel()
+        while clue.button_a:
+            # Wait until button is released
+            time.sleep(0.1)
+        print("RECALIBRATED")
+        clue.play_tone(1440, 0.5)  # Play "reset completed" tone

Clue_Scale/code.py

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+# SPDX-FileCopyrightText: 2022 Jan Goolsbey for Adafruit Industries
+# SPDX-License-Identifier: MIT
+#
+# clue_scale_code.py
+# 2022-07-29 v1.2.0
+#
+# Clue Scale - Single Channel Version
+# Adafruit NAU7802 Stemma breakout example
+
+# import clue_scale_calibrator  # Uncomment to run calibrator method
+
+import time
+import board
+from simpleio import map_range
+from adafruit_clue import clue
+from adafruit_display_shapes.circle import Circle
+from adafruit_display_text.label import Label
+from adafruit_bitmap_font import bitmap_font
+import displayio
+from cedargrove_nau7802 import NAU7802
+
+clue.pixel.brightness = 0.2  # Set NeoPixel brightness
+clue.pixel[0] = clue.YELLOW  # Set status indicator to yellow (initializing)
+
+# Set Scale Defaults
+MAX_GR = 100  # Maximum (full-scale) display range in grams
+DEFAULT_GAIN = 128  # Default gain for internal PGA
+SAMPLE_AVG = 100  # Number of sample values to average
+SCALE_NAME_1 = "COFFEE"  # 6 characters maximum
+SCALE_NAME_2 = "SCALE"  # 6 characters maximum
+
+"""Enter the calibration ratio for the individual load cell in-use. The ratio is
+composed of the reference weight in grams divided by the raw reading. For
+example, a raw reading of 215300 for a 100 gram weight results in a calibration
+ratio of 100 / 215300. Use the clue_scale_single_calibrate method to obtain the
+raw value.
+FYI: A US dime coin weighs 2.268 grams or 0.079 ounces."""
+CALIB_RATIO = 100 / 215300  # load cell serial#4540-02
+
+# Instantiate the Sensor and Display
+nau7802 = NAU7802(board.I2C(), address=0x2A, active_channels=1)
+
+display = board.DISPLAY
+scale_group = displayio.Group()
+
+FONT_0 = bitmap_font.load_font("/fonts/Helvetica-Bold-24.bdf")
+FONT_1 = bitmap_font.load_font("/fonts/OpenSans-16.bdf")
+FONT_2 = bitmap_font.load_font("/fonts/OpenSans-9.bdf")
+
+# Display the Background Bitmap Image
+bkg = displayio.OnDiskBitmap("/clue_scale_bkg.bmp")
+_background = displayio.TileGrid(bkg, pixel_shader=bkg.pixel_shader, x=0, y=0)
+scale_group.append(_background)
+
+# Define and Display the Text Labels and Graphic Elements
+# Place the project name on either side of the graduated scale
+scale_name_1 = Label(FONT_1, text=SCALE_NAME_1, color=clue.CYAN)
+scale_name_1.anchor_point = (0.5, 0.5)
+scale_name_1.anchored_position = (40, 96)
+scale_group.append(scale_name_1)
+
+scale_name_2 = Label(FONT_1, text=SCALE_NAME_2, color=clue.CYAN)
+scale_name_2.anchor_point = (0.5, 0.5)
+scale_name_2.anchored_position = (199, 96)
+scale_group.append(scale_name_2)
+
+# Define the zeroing button graphic
+zero_button_circle = Circle(14, 152, 14, fill=None, outline=clue.RED, stroke=2)
+scale_group.append(zero_button_circle)
+
+zero_button_label = Label(FONT_1, text="Z", color=clue.RED)
+zero_button_label.x = 8
+zero_button_label.y = 150
+scale_group.append(zero_button_label)
+
+# Place tickmark labels next to the graduated scale
+for i in range(-1, 6):
+    tick_value = Label(FONT_2, text=str((MAX_GR) // 5 * i), color=clue.CYAN)
+    if i == -1:
+        tick_value.anchor_point = (1.0, 1.1)
+    elif i == 5:
+        tick_value.anchor_point = (1.0, 0.0)
+    else:
+        tick_value.anchor_point = (1.0, 0.5)
+    tick_value.anchored_position = (99, 201 - (i * 40))
+    scale_group.append(tick_value)
+
+# Place the grams and ounces labels and values near the bottom of the display
+grams_label = Label(FONT_0, text="grams", color=clue.BLUE)
+grams_label.anchor_point = (1.0, 0)
+grams_label.anchored_position = (80, 216)
+scale_group.append(grams_label)
+
+ounces_label = Label(FONT_0, text="ounces", color=clue.BLUE)
+ounces_label.anchor_point = (1.0, 0)
+ounces_label.anchored_position = (230, 216)
+scale_group.append(ounces_label)
+
+grams_value = Label(FONT_0, text="0.0", color=clue.WHITE)
+grams_value.anchor_point = (1.0, 0.5)
+grams_value.anchored_position = (80, 200)
+scale_group.append(grams_value)
+
+ounces_value = Label(FONT_0, text="0.00", color=clue.WHITE)
+ounces_value.anchor_point = (1.0, 0.5)
+ounces_value.anchored_position = (230, 200)
+scale_group.append(ounces_value)
+
+# Define the moveable indicator bubble
+indicator_group = displayio.Group()
+bubble = Circle(120, 200, 10, fill=clue.YELLOW, outline=clue.YELLOW, stroke=3)
+indicator_group.append(bubble)
+
+scale_group.append(indicator_group)
+display.show(scale_group)
+
+
+# Helpers
+def zero_channel():
+    """Prepare internal amplifier settings and zero the current channel. Use
+    after power-up, a new channel is selected, or to adjust for measurement
+    drift. Can be used to zero the scale with a tare weight.
+    The nau7802.calibrate function used here does not calibrate the load cell,
+    but sets the NAU7802 internals to prepare for measuring input signals."""
+    nau7802.calibrate("INTERNAL")
+    nau7802.calibrate("OFFSET")
+
+
+def read(samples=100):
+    """Read and average consecutive raw samples; return averaged value."""
+    sample_sum = 0
+    sample_count = samples
+    while sample_count > 0:
+        if nau7802.available:
+            sample_sum = sample_sum + nau7802.read()
+            sample_count -= 1
+    return int(sample_sum / samples)
+
+
+# Activate the Sensor
+# Enable the internal analog circuitry, set gain, and zero
+nau7802.enable(True)
+nau7802.gain = DEFAULT_GAIN
+zero_channel()
+
+# Play "welcome" tones
+clue.play_tone(1660, 0.15)
+clue.play_tone(1440, 0.15)
+
+# The Primary Code Loop
+# Read sensor, move bubble, and display values
+while True:
+    clue.pixel[0] = clue.GREEN  # Set status indicator to green (ready)
+
+    # Read the raw scale value and scale for grams and ounces
+    value = read(SAMPLE_AVG)
+    mass_grams = round(value * CALIB_RATIO, 1)
+    mass_ounces = round(mass_grams * 0.03527, 2)
+    grams_value.text = f"{mass_grams:5.1f}"
+    ounces_value.text = f"{mass_ounces:5.2f}"
+    print(f" {mass_grams:5.1f} grams   {mass_ounces:5.2f} ounces")
+
+    # Reposition the indicator bubble based on grams value
+    min_gr = (MAX_GR // 5) * -1  # Minimum display value
+    bubble.y = int(map_range(mass_grams, min_gr, MAX_GR, 240, 0)) - 10
+    if mass_grams > MAX_GR or mass_grams < min_gr:
+        bubble.fill = clue.RED
+    else:
+        bubble.fill = None
+
+    # Check to see if the zeroing button is pressed
+    if clue.button_a:
+        # Zero the sensor
+        clue.pixel[0] = clue.RED  # Set status indicator to red (stopped)
+        bubble.fill = clue.RED  # Set bubble center to red (stopped)
+        clue.play_tone(1660, 0.3)  # Play "button pressed" tone
+
+        zero_channel()
+
+        while clue.button_a:
+            # Wait until the button is released
+            time.sleep(0.1)
+
+        clue.play_tone(1440, 0.5)  # Play "reset completed" tone
+        bubble.fill = None  # Set bubble center to transparent (ready)