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Either configuration can be valid, as long as the internal pull-up/pull-down is set correctly.Thanks, makes sense, feed from 3.3v rail and then tie it into an open GPIO port. Need to figure out how I want to add it to the hat.
Thanks for the help as usual :)
I found this old schematic for wiring in float switches, can someone explain the difference?
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reef-pi :: An opensource reef tank controller based on Raspberry Pi.
My 125g tank was setup with RKE controller and several modules. I have been trying to source a new head unit but I was not successful since the company went out of business. Would it be possible to be a reef-pi controller that would reuse some of the RKE module such PB4 power bar, ALC light...www.reef2reef.com
It looks like it was designed for an older rpi since the diagram is 26 pins. I'm not sure if the older pis had a different default pin states.
This looks like it is not expecting to use the internal pull up or pull down resistors. The 10k resistor is a pull up resistor to provide a default state when the switch is open. The 1k serves as the current limit resistor (can also protect against accidentally setting GPIO 18 as a high output if the switch is also closed).
