add example for those without a PM sensor

examples/all-in-one-no-pm.py

@@ -0,0 +1,178 @@
+#!/usr/bin/env python
+
+import time
+import colorsys
+import os
+import sys
+import ST7735
+import ltr559
+
+from bme280 import BME280
+from enviroplus import gas
+from subprocess import PIPE, Popen
+from PIL import Image
+from PIL import ImageDraw
+from PIL import ImageFont
+
+print("""all-in-one.py - Displays readings from all of Enviro plus' sensors
+Press Ctrl+C to exit!
+""")
+
+# BME280 temperature/pressure/humidity sensor
+bme280 = BME280()
+
+# Create ST7735 LCD display class
+st7735 = ST7735.ST7735(
+    port=0,
+    cs=1,
+    dc=9,
+    backlight=12,
+    rotation=270,
+    spi_speed_hz=10000000
+)
+
+# Initialize display
+st7735.begin()
+
+WIDTH = st7735.width
+HEIGHT = st7735.height
+
+# Set up canvas and font
+img = Image.new('RGB', (WIDTH, HEIGHT), color=(0, 0, 0))
+draw = ImageDraw.Draw(img)
+path = os.path.dirname(os.path.realpath(__file__))
+font = ImageFont.truetype(path + "/fonts/Asap/Asap-Bold.ttf", 20)
+
+message = ""
+
+# The position of the top bar
+top_pos = 25
+
+
+# Displays data and text on the 0.96" LCD
+def display_text(variable, data, unit):
+    # Maintain length of list
+    values[variable] = values[variable][1:] + [data]
+    # Scale the values for the variable between 0 and 1
+    colours = [(v - min(values[variable]) + 1) / (max(values[variable])
+               - min(values[variable]) + 1) for v in values[variable]]
+    # Format the variable name and value
+    message = "{}: {:.1f} {}".format(variable[:4], data, unit)
+    print(message)
+    draw.rectangle((0, 0, WIDTH, HEIGHT), (255, 255, 255))
+    for i in range(len(colours)):
+        # Convert the values to colours from red to blue
+        colour = (1.0 - colours[i]) * 0.6
+        r, g, b = [int(x * 255.0) for x in colorsys.hsv_to_rgb(colour,
+                   1.0, 1.0)]
+        # Draw a 1-pixel wide rectangle of colour
+        draw.rectangle((i, top_pos, i+1, HEIGHT), (r, g, b))
+        # Draw a line graph in black
+        line_y = HEIGHT - (top_pos + (colours[i] * (HEIGHT - top_pos)))\
+                 + top_pos
+        draw.rectangle((i, line_y, i+1, line_y+1), (0, 0, 0))
+    # Write the text at the top in black
+    draw.text((0, 0), message, font=font, fill=(0, 0, 0))
+    st7735.display(img)
+
+
+# Get the temperature of the CPU for compensation
+def get_cpu_temperature():
+    process = Popen(['vcgencmd', 'measure_temp'], stdout=PIPE)
+    output, _error = process.communicate()
+    return float(output[output.index('=') + 1:output.rindex("'")])
+
+
+# Tuning factor for compensation. Decrease this number to adjust the
+# temperature down, and increase to adjust up
+factor = 0.8
+
+cpu_temps = [0] * 5
+
+delay = 0.5  # Debounce the proximity tap
+mode = 0  # The starting mode
+last_page = 0
+light = 1
+
+# Create a values dict to store the data
+variables = ["temperature",
+             "pressure",
+             "humidity",
+             "light",
+             "oxidised",
+             "reduced",
+             "nh3"]
+
+values = {}
+
+for v in variables:
+    values[v] = [1] * WIDTH
+
+# The main loop
+try:
+    while True:
+        proximity = ltr559.get_proximity()
+
+        # If the proximity crosses the threshold, toggle the mode
+        if proximity > 1500 and time.time() - last_page > delay:
+            mode += 1
+            mode %= len(variables)
+            last_page = time.time()
+
+        # One mode for each variable
+        if mode == 0:
+            variable = "temperature"
+            unit = "C"
+            cpu_temp = get_cpu_temperature()
+            # Smooth out with some averaging to decrease jitter
+            cpu_temps = cpu_temps[1:] + [cpu_temp]
+            avg_cpu_temp = sum(cpu_temps) / float(len(cpu_temps))
+            raw_temp = bme280.get_temperature()
+            data = raw_temp - ((avg_cpu_temp - raw_temp) / factor)
+            display_text(variable, data, unit)
+
+        if mode == 1:
+            variable = "pressure"
+            unit = "hPa"
+            data = bme280.get_pressure()
+            display_text(variable, data, unit)
+
+        if mode == 2:
+            variable = "humidity"
+            unit = "%"
+            data = bme280.get_humidity()
+            display_text(variable, data, unit)
+
+        if mode == 3:
+            variable = "light"
+            unit = "Lux"
+            if proximity < 10:
+                data = ltr559.get_lux()
+            else:
+                data = 1
+            display_text(variable, data, unit)
+
+        if mode == 4:
+            variable = "oxidised"
+            unit = "kO"
+            data = gas.read_all()
+            data = data.oxidising / 1000
+            display_text(variable, data, unit)
+
+        if mode == 5:
+            variable = "reduced"
+            unit = "kO"
+            data = gas.read_all()
+            data = data.reducing / 1000
+            display_text(variable, data, unit)
+
+        if mode == 6:
+            variable = "nh3"
+            unit = "kO"
+            data = gas.read_all()
+            data = data.nh3 / 1000
+            display_text(variable, data, unit)
+
+# Exit cleanly
+except KeyboardInterrupt:
+    sys.exit(0)