I am attempting the active buzzer tutorial, but no matter what I try my potentiometer will not read anything below a value of 17! it will happily read above 17 up until it reaches 1023 but I cannot turn the knob further than 17 in the other direction - I've tried using another computer, adjusting the position of the control knob and using different connections but all to no avail. Any help?
Help with what? Sounds perfectly normal to me !
@connelsey, your topic has been moved to a more suitable location on the forum.
Get out your DMM (Digital Multi Meter) and measure the resistance of the pot (wiper to each end) with the pot disconnected from the mystery Arduino. Does it go to zero ohms?
To be sure I would like a drawing and certainly a close picture of the project.
I have no problems reading pot values really close to, or at zero.
Hi,
What model Arduino are you using?
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Thanks.. Tom..... 
Potentiometers normally do not short circuit wiper with any of the pins, so this is normal. You can adjust levels programatically to account for the offset
thanks for your help, guess I'll just ignore this reading of 17
Map the range 17 - 1023 into what You want, 0 to 100% or what.
1 Like
Hi,
Can you please post a circuit diagram and a picture of your project?
So we can see your component layout.
Thanks.. Tom...
No it's not, assuming OP is using the UNO that came with his starter kit.
An UNO and a good pot and proper wiring will read 0-1023.
Don't use the map() function as a band-aid. Try to find the problem.
Remove the pot, and connect the analogue input directly to ground with a Dupond wire.
If it reads zero, then the Uno is fine.
You could swap 5volt and ground wires to the pot, to test the other side of the pot.
Leo..
Hi, @connelsey
Do you have a DMM?
If so, can you measure the voltage between the gnd end of the pot and the wiper when you turn the shaft from one end to the other?
Thanks.. Tom...
I'd like to see a proper schematic and some good photos of the real thing.
Usually pot meters go right to their extremes, so should be capable of hitting right down to 0 Ohms just fine.
In general I'd consider preventing the whole analog part and instead use e.g. a rotary encoder.
A pot that consistantly reads a non zero value for the lowest setting is normal, if it was not consistant, then there would be a need to diagnose further. A small resistance at low & high end of the sweep are normal in SOME pots, while the ideal is no resistance to 100%, this is not always the case.
Hi,
That is abnormal, the pot wiper sweeps from terminal to terminal, which are at 0V or 5V so 0 to 1023.
I have never come across a pot that performs oddly like @connelsey , unless it has been zapped at the end by being connected incorrectly.
Tom...
I just grabbed 2 random 50K pots from a pile, both measured 1.8 - 2.2 Ohms at their extreme left. Digital pots have end resistance too, on purpose I guess, to simulate the real thing. It all depends on the quality and resistance value of the pot the OP is using. The higher the resistance the more chance Arduino will measure 0 at the extreme left.
Hi,
That is why we need a reply form @connelsey with a circuit diagram and the value of the potentiometer being used.
1.8R/50000R = 0.0036%
1.8R in an assuming 10K will be
1.8R/10000R = 0.018%
0.018% of 1023 = 0.18414counts, in other words 0.
A count of 17 in a 10,000R = ( 17 / 1023 ) x 10000 = 166.1R
Tom...
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