I have made a preliminary one in this thread
Thank you ill will be giving this a go over next weekend
Hi @robsworld78, can you please help in the step to add DHT22 sensor in Reef-Pi? I've done some test but I can only see the values in the command line... Thank you!Thanks for the kind words, working on bringing back that GUI.For the DHT22 you can run a python script like this, if you edit it so only the humidity is saved to the file you can import it in reef-pi using the file driver. If you can get away from I2C its best, I know it's tempting though with 2 wires vs 16.
How to Setup a Humidity Sensor on the Raspberry Pi
Great for monitoring both temperature and humidity.pimylifeup.com
I have suggested the same thing for sensors in general, e.g. an „error mode“ where values are disregarded and maybe even hand control over to a backup. For pH and Temperature these are the obvious error values of 0 and -1 (or -127 for the DS18B20 on the ESP32, if I remember correctly).
Hi Simon, if you have data in the terminal then it should just be a matter of splitting up the data in it's own CSV file. Here's the code from that link tweaked a bit, untested but should work. You'll have to change the pin number.
import os
import time
import Adafruit_DHT
DHT_SENSOR = Adafruit_DHT.DHT22
DHT_PIN = 4
try:
f = open('/var/lib/reef-pi/dht22/temperature.txt', 'w')
f.write('Temperature\r\n')
f = open('/var/lib/reef-pi/dht22/humidity.txt', 'w')
f.write('Humidity\r\n')
except:
pass
while True:
humidity, temperature = Adafruit_DHT.read_retry(DHT_SENSOR, DHT_PIN)
if humidity is not None and temperature is not None:
f.write('{0},{1},{2:0.1f}*C,{3:0.1f}%\r\n'.format(time.strftime('%m/%d/%y'), time.strftime('%H:%M'), temperature, humidity))
else:
print("Failed to retrieve data from humidity sensor")
time.sleep(30)
No problem but I really messed up the code, that's what I get for rushing, unfortunately I can't edit that post. Still untested but should work. I must get to bed now but tomorrow I'll post a service file so the script runs when the Pi boots.
import os
import time
import Adafruit_DHT
DHT_SENSOR = Adafruit_DHT.DHT22
DHT_PIN = 4
while True:
humidity, temperature = Adafruit_DHT.read_retry(DHT_SENSOR, DHT_PIN)
if temperature is not None:
f = open('/var/lib/reef-pi/dht22/temperature.txt', 'w')
f.write(temperature)
if humidity is not None:
f = open('/var/lib/reef-pi/dht22/humidity.txt', 'w')
f.write(humidity)
time.sleep(30)import os
import time
import Adafruit_DHT
DHT_SENSOR = Adafruit_DHT.DHT22
DHT_PIN = 4
while True:
humidity, temperature = Adafruit_DHT.read_retry(DHT_SENSOR, DHT_PIN)
if temperature is not None:
temp_string = str(temperature)
f = open('/var/lib/reef-pi/dht22/temperature.txt', 'w')
f.write(temp_string)
if humidity is not None:
hum_string = str(humidity)
f = open('/var/lib/reef-pi/dht22/humidity.txt', 'w')
f.write(hum_string)
time.sleep(30)import os
import time
import Adafruit_DHT
DHT_SENSOR = Adafruit_DHT.DHT22
DHT_PIN = 4
while True:
humidity, temperature = Adafruit_DHT.read_retry(DHT_SENSOR, DHT_PIN)
if temperature is not None:
with f = open('/var/lib/reef-pi/dht22/temperature.txt', 'w'):
# go to beginning of the file
f.seek()
# write temperature as a floating point number(f)
# with sign(+), 5 characters (5) and 1 digit(.1)
f.write("{:+5.1f}".format(temperature))
if humidity is not None:
with f = open('/var/lib/reef-pi/dht22/humidity.txt', 'w'):
# go to beginning of the file
f.seek()
# write humidity as a floating point number(f)
# 4 characters (4) and 1 digit(.1)
f.write("{:4.1f}".format(humidity))
time.sleep(30) # in seconds
Looks like you have forgotten the ":" at the end of the line.
with open('var/lib/reef-pi/dht22/temperature.txt') as f: GNU nano 5.4 DHT22_Read.py
import os
import time
import Adafruit_DHT
DHT_SENSOR = Adafruit_DHT.DHT22
DHT_PIN = 4
while True:
humidity, temperature = Adafruit_DHT.read_retry(DHT_SENSOR, DHT_PIN)
if temperature is not None:
with open('/var/lib/reef-pi/dht22/temperature.txt', 'w') as my_file:
# write temperature as a floating point number (f)
# with sign(+), 5 characters (5) and 1 digit(.1)
my_file.write("{:+5.1f}".format(temperature))
if humidity is not None:
with open('/var/lib/reef-pi/dht22/humidity.txt', 'w') as my_file2:
# write humidity as a floating point number(f)
# 4 characters (4) and 1 digit(.1)
my_file2.write("{:4.1f}".format(humidity))
with open('/var/lib/reef-pi/dht22/temperature.txt') as my_file:
print(my_file.read())
time.sleep(10) # in seconds
I think next time I better test.
Glad you guys got it working.[Unit]
Description=reef-pi DHT22
After=network.target
[Service]
ExecStart=/var/lib/reef-pi/dht22/humidity_logger.py
WorkingDirectory=/var/lib/reef-pi/dht22/
StandardOutput=inherit
StandardError=inherit
Restart=always
RestartSec=3
[Install]
WantedBy=multi-user.targetExecStart=/usr/bin/python3 /var/lib/reef-pi/dht22/dht22_read.py
