AllSky - automatic/manual heating/fan control

[jimjackii]

I would like to briefly introduce my control system for dome heating and fans.

The AllSky camera is attached outside on the roof with a view towards the east.

Double relay:
https://www.amazon.de/gp/product/B078Q326KT/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&th=1

Connected via the two relays:

2 high load resistors 22 Ohm 10W parallel to GPIO 23 (Pin16) for the dome heating:
https://www.ebay.de/itm/222611816763?hash=item33d4b2c13b:g:ddAAAOSwKGhZkAc2

2 fans 5VDC 30x30mm parallel to GPIO 24 (Pin18):
https://www.amazon.de/gp/product/B07X93XGBD/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&th=1

The relays are supplied with 3.3VDC (Pin 1) from the RasPi with GND (Pin9).

The relays switch 5VDC (Pin 2) with GND (Pin6), the heating resistors and the fans.

Pictures of the construction:
https://wetter.jimjackii.de/astrocam1/bilder_aufbau/IMG_20211104_165610_res.jpg
https://wetter.jimjackii.de/astrocam1/bilder_aufbau/IMG_20211104_171957_res.jpg
https://wetter.jimjackii.de/astrocam1/bilder_aufbau/IMG_20211104_170050_res.jpg

The housing is a electrical distributor housing with IP55 from the local hardware store.

The 4 "dome is this one:
https://www.amazon.de/gp/product/B01N29BQN6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

The heating and fan are controlled with their own scripts.

The heating / fan are switched automatically, but it is possible to switch the heating / fan manually via the website.
The manual shift has priority over an automatic shift.
Heating / fans are generally only switched on during the day.

The heating is switched on depending on the outside air humidity. The value for the outside air humidity comes
from my weather data from my weather station. Above a certain value, condensation on the dome is to be expected,
then the heating is switched on.

The fans are switched on depending on the outside temperature and the RasPi temperature.
The outside temperature also comes from my weather data from the weather station, the RasPi temperature is sent via
Reading of the RasPi temperature determined.

My scripts:

1. Sunrise / sunset script:
   http://wetter.jimjackii.de/astrocam1/bilder_aufbau/Scripte/astrocam1_check_sau.sh

2. Check temperature / humidity of my weather data (must be adjusted here individually):
   http://wetter.jimjackii.de/astrocam1/bilder_aufbau/Scripte/astrocam1_check_temp.sh

3. Various scripts for switching the GPIO23/24:
   http://wetter.jimjackii.de/astrocam1/bilder_aufbau/Scripte/gpio_23_on.sh
   http://wetter.jimjackii.de/astrocam1/bilder_aufbau/Scripte/gpio_23_off.sh
   http://wetter.jimjackii.de/astrocam1/bilder_aufbau/Scripte/gpio_24_on.sh
   http://wetter.jimjackii.de/astrocam1/bilder_aufbau/Scripte/gpio_24_off.sh
   http://wetter.jimjackii.de/astrocam1/bilder_aufbau/Scripte/gpio_start.sh

4. Website for manual heating / fan switching, which can be integrated into your own website / AllSky website:
   http://wetter.jimjackii.de/astrocam1/bilder_aufbau/Scripte/index.php

The scripts are processed cyclically every 10 minutes using a cron job.

The structure and the controls are "quick-and-dirty", but work to my satisfaction.

Perhaps my information/implementation will be helpful for other AllSky users.
Please contact me if you have any questions or suggestions/improvements.