is it possible to extend the analog inputs on arduino uno from 6 to 200?

i need 200 analog inputs on arduino uno, is it possible to extend the analog inputs on arduino uno from 6 to 200?

Hi, welcome to the forum.

With a mux.

For example 200 inputs to 25 '16-to-1' mux to a single '16-to-1' mux to one analog input of the Arduino. That means you need a total of 26 74HC4067.

I foresee another problem though. Reading all those inputs will be slow, and the Arduino Uno will run out of memory. What are you going to do with all that data ?

Can you tell about your project ? What are the voltages ? is that from 200 sensors ?

There are other options and other chips.

[EDIT] Somehow my calculation has gone wrong. It is as robtillaart writes in reply #2.

for 200 sensors you need 200/16 = 13 + 1 = 14 '16 to 1 mux'

You need at least 8 pins to drive the mux, but for that you could used a shift register, only needing 3 pins.

maybe - http://www.maxwell.com/images/documents/81840rp_rev5.pdf - is an option?
(found it by google, never used this one)

Hi, Thank you.

I want to build a puzzle game With 200 parts and put each part resistor in a different value and in that way identify the parts and to know whether they are in the right place. If someone has another idea how to identify all the parts I'd love to know.

I think it should be possible to distinguish 200 different resistor values. Perhaps a few different ranges has to be made, for example an analog input for low resistor values and another analog input for high resistor values. But I think it can be done.

What about bad contacts ? If the contacts are not 100% good, the resistor value can not be read properly.

Resistor value not too low, to reduce the current through the contacts, and not too high, that introduces noise.
Not linear incremented like : 200, 400, 600, 800, 1000, ... 40k ohm.
But for example the E48 series : 100, 105, 110, 115, 121, 127, 133, 140, ... 1.4M ohm.
Maybe this is not so easy, the 1.4M is very high, but the E96 series will be hard to distinquish.

There are other ways to identify something, but they are far more expensive. Something with a digital tag or so.

You may be better off with capacitors instead of resistors, with no ADC involved, Or you consider to use more than two pins per piece, and give every piece an digital code. Fast and easy to read, easy to multiplex.

How is this reading them? Contacts under each piece?

RFID and multiplex the coils.