Here's how the CLUE will work:
- On start, show a home screen logo with the word "BBQLUE" in a circle with a square at one corner
- Begin scanning for a BLE device advertising the ibbq service
- When such a device is found, connect to it, switch the temperatures screen layout with "BBQLUE" at the top and the probe temperatures listed in color coding
- Watch the A button for presses to switch between Fahrenheit and Celsius
- If connection is lost, swap back to home screen logo and begin scanning again
To use with CircuitPython, you need to first install a few libraries, into the lib folder on your CIRCUITPY drive. Then you need to update code.py with the example script.
Thankfully, we can do this in one go. In the example below, click the Download Project Bundle button below to download the necessary libraries and the code.py file in a zip file. Extract the contents of the zip file, open the directory CLUE_BBQ/ and then click on the directory that matches the version of CircuitPython you're using and copy the contents of that directory to your CIRCUITPY drive.
Your CIRCUITPY drive should now look similar to the following image:
# SPDX-FileCopyrightText: 2020 John Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT
# Adafruit BBQ display works with ibbq protocol-based BLE temperature probes
import time
import displayio
import _bleio
import adafruit_ble
from adafruit_ble.advertising.standard import ProvideServicesAdvertisement
from adafruit_ble_ibbq import IBBQService
from adafruit_clue import clue
from adafruit_display_shapes.circle import Circle
from adafruit_display_text import label
from adafruit_bitmap_font import bitmap_font
clue.display.brightness = 1.0
homescreen_screen = displayio.Group()
temperatures_screen = displayio.Group()
# define custom colors
GREEN = 0x00D929
BLUE = 0x0000FF
RED = 0xFF0000
ORANGE = 0xFF6A00
YELLOW = 0xFFFF00
PURPLE = 0xE400FF
BLACK = 0x000000
WHITE = 0xFFFFFF
BURNT = 0xBB4E00
unit_mode = False # set the temperature unit_mode. True = centigrade, False = farenheit
# Setup homescreen
color_bitmap = displayio.Bitmap(120, 120, 1)
color_palette = displayio.Palette(1)
color_palette[0] = BURNT
bg_sprite = displayio.TileGrid(color_bitmap, x=120, y=0, pixel_shader=color_palette)
homescreen_screen.append(bg_sprite)
clue_color = [GREEN, BLUE, RED, ORANGE, YELLOW, PURPLE]
outer_circle = Circle(120, 120, 119, fill=BLACK, outline=BURNT)
homescreen_screen.append(outer_circle)
title_font = bitmap_font.load_font("/font/GothamBlack-50.bdf")
title_font.load_glyphs("BQLUE".encode("utf-8"))
title_label = label.Label(title_font, text="BBQLUE", color=clue.ORANGE)
title_label.x = 12
title_label.y = 120
homescreen_screen.append(title_label)
clue.display.root_group = homescreen_screen
# Setup temperatures screen
temp_font = bitmap_font.load_font("/font/GothamBlack-25.bdf")
temp_font.load_glyphs("0123456789FC.-<".encode("utf-8"))
my_labels_config = [
(0, "", GREEN, 2, 100),
(1, "", BLUE, 2, 150),
(2, "", RED, 2, 200),
(3, "", ORANGE, 135, 100),
(4, "", YELLOW, 135, 150),
(5, "", PURPLE, 135, 200),
]
my_labels = {} # dictionary of configured my_labels
text_group = displayio.Group()
for label_config in my_labels_config:
(name, text, color, x, y) = label_config # unpack a tuple into five var names
templabel = label.Label(temp_font, text=text, color=color)
templabel.x = x
templabel.y = y
my_labels[name] = templabel
text_group.append(templabel)
temperatures_screen.append(text_group)
temp_title_label = label.Label(title_font, text="BBQLUE", color=clue.ORANGE)
temp_title_label.x = 12
temp_title_label.y = 30
temperatures_screen.append(temp_title_label)
# PyLint can't find BLERadio for some reason so special case it here.
ble = adafruit_ble.BLERadio() # pylint: disable=no-member
ibbq_connection = None
while True:
# re-display homescreen here
clue.display.root_group = homescreen_screen
print("Scanning...")
for adv in ble.start_scan(ProvideServicesAdvertisement, timeout=5):
clue.pixel.fill((50, 50, 0))
if IBBQService in adv.services:
print("found an IBBq advertisement")
ibbq_connection = ble.connect(adv)
print("Connected")
break
# Stop scanning whether or not we are connected.
ble.stop_scan()
try:
if ibbq_connection and ibbq_connection.connected:
clue.pixel.fill((0, 0, 50))
ibbq_service = ibbq_connection[IBBQService]
ibbq_service.init()
while ibbq_connection.connected:
if clue.button_a: # hold a to swap between C and F
print("unit_mode swapped")
unit_mode = not unit_mode
clue.red_led = True
clue.play_tone(1200, 0.1)
clue.red_led = False
time.sleep(0.1) # debounce
temps = ibbq_service.temperatures
batt = ibbq_service.battery_level
if temps is not None:
probe_count = len(temps) # check how many probes there are
for i in range(probe_count):
if temps[i] != 0 and temps[i] < 1000: # unplugged probes
if unit_mode:
clue.pixel.fill((50, 0, 0))
temp = temps[i]
my_labels[i].text = "{} C".format(temp)
clue.pixel.fill((0, 0, 0))
print("Probe", i + 1, "Temperature:", temp, "C")
else: # F
clue.pixel.fill((50, 0, 0))
temp = temps[i] * 9 / 5 + 32
my_labels[i].text = "{} F".format(temp)
clue.pixel.fill((0, 0, 0))
print("Probe", i + 1, "Temperature:", temp, "F")
else:
print(
"Probe", i + 1, "is unplugged",
)
my_labels[i].text = " ---"
clue.display.root_group = temperatures_screen
except _bleio.ConnectionError:
continue
Libraries
First, we'll import the necessary libraries, including those needed for displayio, BLE, adafruit_clue, shapes, text, fonts, and the iBBQ service.
import time import displayio import _bleio import adafruit_ble from adafruit_ble.advertising.standard import ProvideServicesAdvertisement from adafruit_ble_ibbq import IBBQService from adafruit_clue import clue from adafruit_display_shapes.circle import Circle from adafruit_display_text import label from adafruit_bitmap_font import bitmap_font
Display Groups
We'll set up two different displayio Groups, you can think of these as two distinct screens that we and switch between. One for the homescreen logo, the other for the temperature readouts.
clue.display.brightness = 1.0 homescreen_screen = displayio.Group() temperatures_screen = displayio.Group()
Variables
We'll use a few different colors throughout the code, so here we'll create a set of variables that give us nice names to use for specific color hex values.
We'll also create a variable called unit_mode to switch between Celsius and Fahrenheit.
GREEN = 0x00D929 BLUE = 0x0000FF RED = 0xFF0000 ORANGE = 0xFF6A00 YELLOW = 0xFFFF00 PURPLE = 0xE400FF BLACK = 0x000000 WHITE = 0xFFFFFF BURNT = 0xBB4E00 unit_mode = False # set the temperature unit_mode. True = celsius, False = fahrenheit
Homescreen
Here we will set up the homescreen. This will consist of a 120x120 pixel square in the upper right corner called bg_sprite, in the BURNT umber color.
The displayio system is a hierarchy of objects with a displayio.Group at the top of the hierarchy. In this case, we append the bg_sprite object to the homescreen_screen group.
We next create a black circle with a BURNT outline named outer_circle and append it, too, too the homescreen_screen group.
To add the BBQLUE title, we load a bitmap font, preload the glyphs (characters) we'll need, and create a label object named title_label. The label is positioned on x and y at the center of the screen, and then it is appended to the homescreen_screen group.
Finally, we show all of this on the CLUE display with the clue.display.root_group = homescreen_screen command.
color_bitmap = displayio.Bitmap(120, 120, 1)
color_palette = displayio.Palette(1)
color_palette[0] = BURNT
bg_sprite = displayio.TileGrid(color_bitmap, x=120, y=0, pixel_shader=color_palette)
homescreen_screen.append(bg_sprite)
clue_color = [GREEN, BLUE, RED, ORANGE, YELLOW, PURPLE]
outer_circle = Circle(120, 120, 119, fill=BLACK, outline=BURNT)
homescreen_screen.append(outer_circle)
title_font = bitmap_font.load_font("/font/GothamBlack-50.bdf")
title_font.load_glyphs("BQLUE".encode('utf-8'))
title_label = label.Label(title_font, text="BBQLUE", color=clue.ORANGE)
title_label.x = 12
title_label.y = 120
homescreen_screen.append(title_label)
clue.display.root_group = homescreen_screen
Temperature Screen
The temperature_screen is created in much the same way as the homescreen_screen. However, there will be no bitmap shapes, only text.
Since we want a different position and color for each label correlated to a temperature probe, we create a list of tuples called my_labels_config to contain these values. Each tuple (set of multiple values) in the list represents one of the temperature probes.
By creating the my_labels dictionary, we can unpack the list of tuples into nicely named objects such as "name", "text", "color", and so on, instead of referring to them as indexed numbers.
We'll append each of these label objects to a text group with their corresponding colors and positions, and then append the text group to the temperatures_screen.
We won't show this screen yet, however. We'll wait until we've received data from a sensor.
temp_font = bitmap_font.load_font("/font/GothamBlack-25.bdf")
temp_font.load_glyphs("0123456789FC.-<".encode('utf-8'))
my_labels_config = [(0, "", GREEN, 2, 100),
(1, "", BLUE, 2, 150),
(2, "", RED, 2, 200),
(3, "", ORANGE, 135, 100),
(4, "", YELLOW, 135, 150),
(5, "", PURPLE, 135, 200)
]
my_labels = {} # dictionary of configured my_labels
text_group = displayio.Group()
for label_config in my_labels_config:
(name, text, color, x, y) = label_config # unpack a tuple into five var names
templabel = label.Label(temp_font, text=text, color=color)
templabel.x = x
templabel.y = y
my_labels[name] = templabel
text_group.append(templabel)
temperatures_screen.append(text_group)
temp_title_label = label.Label(title_font, text="BBQLUE", color=clue.ORANGE)
temp_title_label.x = 12
temp_title_label.y = 30
temperatures_screen.append(temp_title_label)
BLE Prep
The radio is instantiated and a variable called ibbq_connection is created to hold the status of connections to a device advertising the ibbq service.
ble = adafruit_ble.BLERadio() # pylint: disable=no-member ibbq_connection = None
Main Loop
Here's the main loop of the code that repeats over and over now that things are set up.
The homescreen_screen is redrawn (this will be useful later when a connection is dropped).
Then, any BLE advertisements that are found are checked to see if they are advertising the ibbq service. If found, we connect!
while True:
# re-display homescreen here
clue.display.root_group = homescreen_screen
print("Scanning...")
for adv in ble.start_scan(ProvideServicesAdvertisement, timeout=5):
clue.pixel.fill((50, 50, 0))
if IBBQService in adv.services:
print("found an IBBq advertisement")
ibbq_connection = ble.connect(adv)
print("Connected")
break
# Stop scanning whether or not we are connected.
ble.stop_scan()
Connected
Once the CLUE is connected to a device with the ibbq service available, the service is initialized so it will send data.
try:
if ibbq_connection and ibbq_connection.connected:
clue.pixel.fill((0, 0, 50))
ibbq_service = ibbq_connection[IBBQService]
ibbq_service.init()
while ibbq_connection.connected:
Button Unit Swap
In order to switch between Fahrenheit and Celsius, we set up the clue.button_a. It will flip the unit_mode between True and False each time it is pressed, as well as play a small beep on the built-in buzzer so the user knows the press has been registered.
if clue.button_a: # hold a to swap between C and F
print("unit_mode swapped")
unit_mode = not unit_mode
clue.red_led = True
clue.play_tone(1200, 0.1)
clue.red_led = False
time.sleep(0.1) # debounce
Temperature Display
To read and display the temperature data coming from each probe, first a variable called temps is set to the values of the ibbq_service.temperatures attribute that has been received from the BLE temperature device.
If the temps value is not None (at first when the devices connect this value is empty, so we ignore that until real data comes through) we then iterate through each probe value that has been received.
If the value isn't 0 and is less than 1000, it means there is a temperature probe plugged into that port.
Depending on the unit_mode we will then display the Celsius value directly, or first calculate the Fahrenheit value with the formula * 9 / 5 +32.
This value is displayed in the proper label color and position on screen, and then this is repeated for each subsequent probe.
If the value is 0 or greater than 1000, then there is not a probe plugged in and we'll display three dashes "---".
Once the labels are updated we re-draw the screen with the clue.display.root_group = temperatures_screen command.
temps = ibbq_service.temperatures
batt = ibbq_service.battery_level
if temps != None:
probe_count = len(temps) # check how many probes there are
for i in range(probe_count):
if temps[i] is not 0 and temps[i] < 1000: # unplugged probes
if unit_mode:
clue.pixel.fill((50, 0, 0))
temp = temps[i]
my_labels[i].text = "{} C".format(temp)
clue.pixel.fill((0, 0, 0))
print("Probe", i + 1, "Temperature:", temp, "C")
else: # F
clue.pixel.fill((50, 0, 0))
temp = temps[i] * 9 / 5 + 32
my_labels[i].text = "{} F".format(temp)
clue.pixel.fill((0, 0, 0))
print("Probe", i + 1, "Temperature:", temp, "F")
else:
print(
"Probe", i + 1, "is unplugged",
)
my_labels[i].text = " ---"
clue.display.root_group = temperatures_screen
Connection Lost
If the connection is lost, we go back to the top and draw the homescreen_screen will attempting to find a new connection!
except _bleio.ConnectionError:
continue
Page last edited February 24, 2025
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