Unused IO Pins, Re-purposing Dimming Port

Basic / Standard Reef Angel hardware
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silkjc
Posts: 11
Joined: Sat Aug 27, 2016 6:51 am

Unused IO Pins, Re-purposing Dimming Port

Post by silkjc »

Hi guys,
I have an RA+ with salinity and wifi expansion.
I use both ATO ports for float valves, but wish to hook up a third float for skimmer over-flow protection. Since I don't really want to buy the IO module + expansion hub just for 1 input, I though perhaps I could re-purpose one of the dimming ports.

Looking at the schematic the PWM_DAYLIGHT pin is connected to (OC2A/PCINT4)PB4. Would I be able to wire the daylight PWM signal port via the float switch and a resistor to ground and write some custom code to treat it as a general IO? Are there any other easier ways?

Are any other IO pins exposed on the PCB to a pad or connection point? I'm not adverse to soldering onto the PCB in the RA unit, as I see in the schematic there are many unused ports (potentially not broken out from the tiny IC pads though). Any suggestions?

Thanks!
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: Unused IO Pins, Re-purposing Dimming Port

Post by rimai »

Hummm. The actinic and daylight channels are used inside the relay box.
There is a signal booster inside the relay box to convert the 0-5V to 0-10V.
If you remove the booster, you would use it as a general purpose I/O.
Another option is to use one of the ICSP pins for your purpose.
I hope this helps.
Roberto.
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