Can an analog input of two or more separate Arduinos be connected to the same point of a simple voltage divider? Background: I have a home automation/security "control" with several push buttons connected in a simple voltage divider such that one analog input can be decoded for which button(s) were pressed. I would like two separate Arduinos to receive the same "command" from that control button set on the voltage divider. The Arduino Megas would most likely have separate 5v power sources but a common ground. They would be approx. 50' apart with a 18awg common ground. Reading an exact value is not necessary since the code looks for a Hi/Lo value to match and could even be different for the separate Arduinos. Thanks.
Yes, both can be fed from the same analog source. The farther one might see a slightly lower level.
Things will go wrong if one Arduino is powered-up and the other is not powered. Inputs to the microcontroller chip have protection diodes which will conduct if an input voltage exceeds the chip's supply voltage (by more than about 0.5 volts). It may be possible to damage the chip if the current is not limited in some way. In practice it may simply result in the powered-up Arduino getting an incorrect input voltage when a button is pressed.
If the analog voltage is coming from a voltage divider, then by definition it will have a series resistor from the source already.
CrossRoads: If the analog voltage is coming from a voltage divider, then by definition it will have a series resistor from the source already.
I had considered that but did not wish to put more detail in my post. Apart from the issue of limiting the current, it would make sense if one button connects directly to Vcc.