adding battery monitor project code

Adding code and assets for the Feather battery monitor project guide

Feather_TFT_Battery_Monitor/code.py

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+# SPDX-FileCopyrightText: 2024 Liz Clark for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+import ssl
+import os
+import socketpool
+import wifi
+import board
+import digitalio
+import displayio
+import vectorio
+from adafruit_bitmap_font import bitmap_font
+from adafruit_display_text import bitmap_label
+import adafruit_imageload
+from adafruit_io.adafruit_io import IO_HTTP, AdafruitIO_RequestError
+import adafruit_max1704x
+import adafruit_requests
+from simpleio import map_range
+from adafruit_ticks import ticks_ms, ticks_add, ticks_diff
+
+# states
+send_io = True
+bat_clock = ticks_ms()
+bat_timer = 60 * 1000
+first_run = True
+# settings.toml imports
+aio_username = os.getenv('AIO_USERNAME')
+aio_key = os.getenv('AIO_KEY')
+# connect to wifi
+wifi.radio.connect(os.getenv('CIRCUITPY_WIFI_SSID'), os.getenv('CIRCUITPY_WIFI_PASSWORD'))
+pool = socketpool.SocketPool(wifi.radio)
+requests = adafruit_requests.Session(pool, ssl.create_default_context())
+io = IO_HTTP(aio_username, aio_key, requests)
+try:
+    # get feed
+    battery_feed = io.get_feed("battery-monitor")
+except AdafruitIO_RequestError:
+    # if no feed exists, create one
+    battery_feed = io.create_new_feed("battery-monitor")
+# default group
+group = displayio.Group()
+# text only group
+textOnly_group = displayio.Group()
+board.DISPLAY.root_group = group
+# palette for vector graphics
+palette = displayio.Palette(5)
+palette[0] = 0xFF0000
+palette[1] = 0xFFFF00
+palette[2] = 0x00FF00
+palette[3] = 0x0000FF
+palette[4] = 0x000000
+# battery rectangle
+rect = vectorio.Rectangle(pixel_shader=palette, width=72, height=45, x=140, y=70, color_index = 0)
+group.append(rect)
+text_bg = vectorio.Rectangle(pixel_shader=palette, width=115, height=70,
+                             x=120, y=60, color_index = 4)
+# io indicator circle
+circle = vectorio.Circle(pixel_shader=palette, radius=8, x=10, y=10, color_index=3)
+textOnly_group.append(circle)
+# graphics bitmap
+bitmap, palette_bit = adafruit_imageload.load(
+    "/bat_bg.bmp",
+    bitmap=displayio.Bitmap,
+    palette=displayio.Palette,
+)
+# purple is made transparent
+palette_bit.make_transparent(0)
+tile_grid = displayio.TileGrid(bitmap, pixel_shader=palette_bit)
+group.append(tile_grid)
+group.append(circle)
+# font for graphics
+sm_file = "/roundedHeavy-26.bdf"
+sm_font = bitmap_font.load_font(sm_file)
+# font for text only
+lg_file = "/roundedHeavy-46.bdf"
+lg_font = bitmap_font.load_font(lg_file)
+volt_text = bitmap_label.Label(sm_font, text=" V", x=150, y=33)
+group.append(volt_text)
+big_volt_text = bitmap_label.Label(lg_font, text=" V")
+big_volt_text.anchor_point = (0.5, 0.0)
+big_volt_text.anchored_position = (board.DISPLAY.width / 2, 0)
+textOnly_group.append(big_volt_text)
+percent_text = bitmap_label.Label(sm_font, text=" %", x=150, y=90)
+big_percent_text = bitmap_label.Label(lg_font, text=" %", x=board.DISPLAY.width//2, y=90)
+big_percent_text.anchor_point = (0.5, 1.0)
+big_percent_text.anchored_position = (board.DISPLAY.width / 2, board.DISPLAY.height - 15)
+textOnly_group.append(big_percent_text)
+
+# buttons
+button0 = digitalio.DigitalInOut(board.D0)
+button0.direction = digitalio.Direction.INPUT
+button0.pull = digitalio.Pull.UP
+button0_state = False
+button1 = digitalio.DigitalInOut(board.D1)
+button1.direction = digitalio.Direction.INPUT
+button1.pull = digitalio.Pull.DOWN
+button1_state = False
+button2 = digitalio.DigitalInOut(board.D2)
+button2.direction = digitalio.Direction.INPUT
+button2.pull = digitalio.Pull.DOWN
+button2_state = False
+
+# MAX17048 instantiation
+monitor = adafruit_max1704x.MAX17048(board.I2C())
+monitor.activity_threshold = 0.01
+
+# colors for battery graphic
+def get_color(value):
+    if value < 30:
+        return 0
+    elif 30 <= value <= 75:
+        return 1
+    else:
+        return 2
+
+while True:
+    # reset button state on release
+    if button0.value and button0_state:
+        button0_state = False
+    if not button1.value and button1_state:
+        button1_state = False
+    if not button2.value and button2_state:
+        button2_state = False
+    # toggle sending to adafruit io
+    if not button0.value and not button0_state:
+        button0_state = True
+        send_io = not send_io
+        if send_io:
+            circle.color_index = 3
+        else:
+            circle.color_index = 4
+    # toggle graphics or text only
+    if button1.value and not button1_state:
+        button1_state = True
+        if board.DISPLAY.root_group == group:
+            board.DISPLAY.root_group = textOnly_group
+        else:
+            board.DISPLAY.root_group = group
+    # toggle battery graphic or % text
+    if button2.value and not button2_state:
+        button2_state = True
+        if len(group) > 4:
+            group.pop()
+            group.pop()
+        else:
+            group.append(text_bg)
+            group.append(percent_text)
+    # read MAX17048 every 60 seconds
+    if first_run or ticks_diff(ticks_ms(), bat_clock) >= bat_timer:
+        first_run = False
+        battery_volts = monitor.cell_voltage
+        battery_percent = monitor.cell_percent
+        print(f"Battery voltage: {battery_volts:.2f} Volts")
+        print(f"Battery percentage: {battery_percent:.1f} %")
+        print()
+        battery_display = map_range(battery_percent, 0, 100, 0, 72)
+        battery_x = map_range(battery_percent, 0, 100, 210, 140)
+        #  update rectangle to reflect battery charge
+        rect.width = int(battery_display)
+        rect.x = int(battery_x)
+        rect.color_index = get_color(battery_percent)
+        volt_text.text = f"{battery_volts:.2f} V"
+        percent_text.text = f"{battery_percent:.1f} %"
+        big_volt_text.text = f"{battery_volts:.2f} V"
+        big_percent_text.text = f"{battery_percent:.1f} %"
+        if battery_percent >= 100 and send_io:
+            io.send_data(battery_feed["key"], battery_percent)
+        bat_clock = ticks_add(bat_clock, bat_timer)