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Topic: 15 sensors in series: 1x5v or 15x5v? (Read 973 times) previous topic - next topic

Anachrocomputer

To do what you want, i.e. to read each of the 15 sensors individually, you'll need the circuit that you drew with the 15 220 Ohm resistors. Otherwise, you won't be able to sense the resistance changes independently (one sensor will affect reading for all the others).

Is there any reason you can't build the version with 15 220 Ohm resistors?

brendan mccloskey

Ok
now I understand, my OP was a little misleading (suggesting only one 220R); correct, I am using 15x220R, but my readings changed and I assumed there was a error in my circuit. My other error was assuming that sensor1 would get 5v (being physically closest to the 5v pin) and sensor 15 would get something less than 5v, being furthest away.

Thanks
Brendan

Anachrocomputer


My other error was assuming that sensor1 would get 5v (being physically closest to the 5v pin) and sensor 15 would get something less than 5v, being furthest away.


As long as they're wired together with copper wire (i.e. not using conductive plastics, etc.) then they'll all be at 5V. I think my misunderstanding was when you said "in series", which will not result in all the "top" ends of the sensors being at 5V. Look up the difference between a "series" circuit and a "parallel" circuit. In this case, you need a parallel circuit, so that all the sensors are independent.

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