import adafruit_si7021
import board
import busio
import digitalio
import gc
import math
import microcontroller
import neopixel
import time
# PINs
pixel = neopixel.NeoPixel(board.NEOPIXEL, 1)
pixel[0] = (0, 0, 10)
redled = digitalio.DigitalInOut(board.D13)
redled.direction = digitalio.Direction.OUTPUT
sgnd = digitalio.DigitalInOut(board.D5)
sgnd.direction = digitalio.Direction.OUTPUT
sv0 = digitalio.DigitalInOut(board.D6)
sv0.direction = digitalio.Direction.OUTPUT
svin = digitalio.DigitalInOut(board.D9)
svin.direction = digitalio.Direction.OUTPUT
redled.value = True
sgnd.value = False
sv0.value = True
svin.value = True
# si7021 sensor
time.sleep(1)
i2c = busio.I2C(board.SCL, board.SDA)
sensor = adafruit_si7021.SI7021(i2c)
# calculate current Vapour-pressure deficit
def vpd(temp, rh):
# Estimated Saturation Pressures
# Saturation Vapor Pressure method 1
es1 = 0.6108 * math.exp(17.27 * temp / (temp + 237.3))
# Saturation Vapor Pressure method 2
es2 = 6.11 * 10**((7.5 * temp) / (237.3 + temp)) / 10
# Saturation Vapor Pressure method 3
es3 = 6.112 * math.exp(17.62 * temp / (temp + 243.12)) / 10
# Saturation Vapor Pressure mean
es = (es1 + es2 + es3) / 3
# actual partial pressure of water vapor in air
ea = rh / 100 * es
# return Vapour-pressure deficit
vpd = es - ea
return vpd
# write to SD card
def sdwrite(sdlog):
with open("/logs/vpd.txt", "a") as fp: # open to add line to log.txt
redled.value = True # turn on Red LED when SD in use
print(sdlog) # print what your about to write to SD
fp.write(sdlog) # write to SD
fp.flush() # what does this do, hope it helps????
redled.value = False # turn off Red LED when SD is done
pixel[0] = (0, 0, 0)
print("Basic Logging of Vapour-pressure Deficit to filesystem")
# write at start or reset
sdwrite('-Reset-\r\n')
sdwrite('\r\n')
while True:
try:
pixel[0] = (10, 0, 10)
# CPU temperature
cput = microcontroller.cpu.temperature
# write to text filesystem
sdwrite('CPU Temp = {}\r\n'.format(round(cput, 1)))
sdwrite('Sensor: C {}'.format(round(sensor.temperature, 1)))
sdwrite(', F {}'.format(round((sensor.temperature * 1.8 + 32), 1)))
sdwrite(', {}%\r\n'.format(round(sensor.relative_humidity), 1))
currentVPD = vpd(sensor.temperature, sensor.relative_humidity)
sdwrite('VPD = {}\r\n'.format(round(currentVPD, 2)))
sdwrite('\r\n')
pixel[0] = (0, 0, 0)
gc.collect()
print(gc.mem_free())
# blink and neopixel yellow after writing for 3 seconds
for i in range(3):
redled.value = True
pixel[0] = (0, 0, 0)
time.sleep(0.5)
pixel[0] = (2, 2, 0)
redled.value = False
time.sleep(0.5)
# Blink and neopixel green while waiting 9.5 mins before writing again
for i in range(270):
pixel[0] = (0, 0, 0)
time.sleep(1)
pixel[0] = (0, 5, 0)
time.sleep(1)
# Blink and neopixel green faster for 27 sec when about to write
for i in range(67):
pixel[0] = (0, 0, 0)
time.sleep(0.2)
pixel[0] = (0, 5, 0)
time.sleep(0.2)
# blink and neopixel red faster for 3 sec when about to write
for i in range(8):
redled.value = True
pixel[0] = (0, 0, 0)
time.sleep(0.2)
pixel[0] = (5, 0, 0)
redled.value = False
time.sleep(0.2)
# skip errors but try to print them
except OSError as oe:
print('OSError = ', oe)
time.sleep(1)
pass
except RuntimeError as re:
print('RuntimeError = ', re)
time.sleep(1)
pass
