the wire connected between the Arduino and the FSR.
the fact my reading was noisy when connecting the fat between ground and A0, but was just fine between Vcc and A0 - it mean I should wire it like that? (between Vcc and A0)
Two wires are required to connect an FSR to an Arduino, and presumably they are both long. it would help if you posted a more informative diagram showing the long connections.
Wrong wire choice.
Cable with a grounded shield will minimise interference pickup.
Wire size doesn't matter, since current flow is very low.
For shielded wire you need the pull up choice.
Note that some of the code must be different for pull up/down.
Leo..
Right type of cable. Solderable depends on what metal the cable is made off.
But I have never seen that type of cable that can't be soldered.
You can always use a joiner block if soldering is an issue.
Leo..
just to make sure: in your picture I should refer to only 1 pair of wires see picture:
The red wire goes on one side to FSR pin 1 and on the other side to arduino A0. the other wire (the shielded copper wire) connected on one side to the FSR pin 2 and on the other side to arduino GND. Is that right?
Correct, and shielded wire is a better solution to stop RF being picked up.
The 10m normal wire you had before is a very good aerial.
The stereo wire I linked to is the cheapest option.
It easily rips apart for two lengths of wire.
I can't explain why pull up or pull down is different. It shouldn't.
Show pictures of your setup.
Pull up is recommended because there is no power wire to the sensor that can short out.
Leo..
because maybe there is other consideration that I don’t know of.
Maybe in the environment I check (at my home) using the pulldown resistor (and FSR between Vcc and A0) I get nice and stable reading. but if I will place it in different place I will get lots more noise ?
So if this is the only reason to go with pullup instead of pulldown - and if in my test using pulldown resistor was much cleaner - If I will completely isolate the VCC cable at the FSR side, I should be fine.
For what I try in the past the shielded cable are not easy to work with as opposed to 2 core silicone 24 AWG I used before which are much more flexible.
