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analoque input

How to use two analogue devices with only one analoque input?

For now it's theory, it's for a future evolution of a future project (yeah i know that's two "future")
Ok actually i'll need 3 analogue inputs (one SRF05 ultrasonic rangefinder and one 2-axis accelerometer), but the 18x picaxe chip has only two. So basically, i need to find a way to share one of the inputs. As i won't need to read the all inputs at the same time, maybe it's doable.

So two ideas came to my mind, each one with its pros and cons.


First idea : a SPDT relay.

With that, two solutions :