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Can someone who knows electronics take a look at the attached diagram, and validate it as a working idea?

I want to be able to count the number of closed switched by reading the analog in.

("Pins" are an arduino.)

@george_
The way you have it, the analog pin will always read 5V no matter how many switches are closed.
You need to add a resistor from the analog pin to gnd.
I recommend putting higher value resistors to avoid loading the power supply too much...

@jerrytres @george_ Probably take a look at bypass capacitors and ferrite beads for smooth er transitions.

@krag @jerrytres Thanks, good starting point if I find noise to be an issue.

@jerrytres Thank you, probably saved me a good few hours of confusion.

I can kind of reason why it needs to go to ground, but does it need to go to ground after the switches and resistors, not before?

@george_ yes it needs to be after the switches. (R1 + R2 + R3 + R4) and R5 create a voltage divider.
en.m.wikipedia.org/wiki/Voltag

@george_ if you're also interested in which of these buttons are closed and not just the number of closed buttons, you could use (slightly) different values for the R1-R5 resistors.

If you use e.g. 1k as R1, 1k + 22 Ohm as R2 etc. you should still be able to do a quite simple evaluation of the number of pressed buttons, by comparing to the voltage/ADC ranges for X buttons pressed.

@george_ Determine the max and min for a range by "pressing"=substituting-with-0 the X number of Resistors starting from the lowest values (min) and the highest values (max) via the formula given by @jerrytres .

E.g. if R1 has the lowest value and R4 has the highest one, you can get the min voltage for 3 buttons pressed by substituting R1,R2,R3 with 0 in that formula and the max value by substituting R4,R3,R2 with 0.

If the variations in the values are small, the ranges won't overlap.

@george_ if later on you decide to also care about wich exact button-combination is pressed, you can determine all the values for each combination with the same approach (I would use a spreadsheet) and compare to these (+tolerance) instead of the ranges determined in the previous approach.

The Arduino has a 10bit ADC? I believe (unverified) that should be accurate enough when using 1k, 1022, 1033, 1056 Ohms as R1 to R4 and 2k Ohms as R5 (again using @jerrytres post as base).

@dwagenk @jerrytres Interesting idea. Kinda like file permissions. I'm planning to coarsely read remaining water in a barrel, so they should only switch in a single order, so I can keep it simple. I'm already starting to think a single switch warning me that it's nearly empty is probably enough. But I like to graph things, so would like having more data points.

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