So I took some time and figured out how to use regular float switches in a simple fashion using the built in pi resistors. This makes me happy because I don't have to have extra wiring and soldering tasks when adding a bunch of switches, and I don't have to pay for something I already bought. So to get regular float switches (or any switches for that matter) working safely you can do this...
Step A) create a python script to control the pull up resistance. From the terminal...
sudo nano switches.py
#switches.py
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(21, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(20, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(16, GPIO.IN, pull_up_down=GPIO.PUD_UP)
ctrl+X > Y > <enter>
Step B) make the file executable...
sudo chmod 755 switches.py
Step C) make the script run at startup by adding a line just before "exit" in rc.local (note: the python start command must point to the directory from root /...
sudo nano /etc/rc.local
sudo python /home/pi/switches.py &
ctrl+X > Y > <enter>
Step D) Restart or Reboot
sudo reboot
Step E) Plug your float switch wires into the GPIO. One wire to Pi header connected Ground, and one to the GPIO you used in switches.py
Step F) Check to see if your script is running...
ps -aef | grep python
Step G) Designate those pins in Reef-Pi to inlets/ATO for your application.
Hope this helps, working for me here.
