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Topic: [SOLVED]: Analog values through multiplexer are very inconsistent! (Read 2560 times) previous topic - next topic

dieselboris


What value of capacitor? Make it smaller.


I did but the readings became less consistent.

dieselboris


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hmm according to the tutorial in bildr its not neccessary,

No you misread that.


hmmm i did indeed, will throw myself from the balcony later cos this was indeed the problem (3 days i was banging my head over this grrr).

Guess the output pins always give something so there random channels on the mux where selected?

RIDDICK

#17
Jun 18, 2012, 10:56 am Last Edit: Jun 18, 2012, 10:59 am by RIDDICK Reason: 1
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this was indeed the problem

good to read that...

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Guess the output pins always give something so there random channels on the mux where selected?

the wires between the arduino and the MUX pick up some voltage, so that they swing between 0 and 1...

i wouldnt use a cap on the MUX output... together with the resistance of the MUX path... it works like a low pass... do u need to suppress any noise on the output of ur sensor?

btw: it is normal to miss a little detail sometimes...  ;)
-Arne

dieselboris


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nut i'll give it try!

yup - give it a try...  *wag tail* ;)


shame on me, shame on me.......

thanks for all the efforts!

Grumpy_Mike

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Guess the output pins always give something so there random channels on the mux where selected?


No what it was that those pins were defined as inputs. Then your attempts to drive them high and low simply had the effect of switching on and off the weak 30K pull up resistor on and off. So the pins went between just a logic one and floating. This is enough of an effect to see something happening but just not the right thing.

dieselboris


i wouldnt use a cap on the MUX output... together with the resistance of the MUX path... it works like a low pass... do u need to suppress any noise on the output of ur sensor?


removed the cap indeed, i thought there was a lot of noise but there wasnt actually.

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