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why does the value of potentiometer change even if it is ... ?

hello guys,

i need to know please why does a potentiometer value change even if i turned it into the max which should be 1023 ?

what i am doing here is just testing, so i programmed a simple potentiometer program with serial connection to view the variable on monitor so it's giving me once 1023 , one 0, once 775 ... why ?

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bdk6's picture

Most breadboards are about the same.  The really, really cheap ones are, well, really, really cheap.  You can pay a LOT of money and get one that is somewhat better, but not much.  Or you can buy an average quality one and replace it cheaply every couple years or so, as you should anyway.  On some you can remove the little connecting jumpers from the bottom and replace them, so you can use some good ones from one damaged board to repair another damaged board.  But as has been pointed out they are not designed for heavy use or long term use.

firashelou's picture

aha ok and maybe because i am using a homemade jumper wires which i soldered them by myself, so it might be another reason but when i use it directly to arduino without breadboard they work fine

6677's picture

Ultimately a breadboard is for prototyping only. You wouldn't keep a circuit breadboarded forever. You would solder it up permanently instead, whether that be on a PCB, piece of proto board, cardboard (as a proto board substitute) or even just a bare mess of wires and components soldered to each other.

They are electrically noisy environments highly prone to interference. They are a breeding ground for poor connections (resulting in your issue). They are however a good way to prototype that a circuit layout is generally correct and allow you to quickly change things as you need.

firashelou's picture

sure it's just for testing but this problem is annoying !! does a better breadboard have this issue or not ?

6677's picture

I don't have any breadboards so can't speak from experience. From what I hear, minimise the distance a signal has to propagate through the breadboard, ie a component and its connecting wire need to be as close as possible. Newer breadboards have a tighter grip on components which helps.

 

Even so, a new breadboard with adjacent holes used will be noisier than a permanently built circuit.

 

 

I think you have established your potentiometer works. Your rf modules should be safe to breadboard. Time to test them.

firashelou's picture

exactly !! it's because the breadboard nevertheless it's new one !! when i plugged the potentiometer directly to the arduino it works without giving me the 0 value when it's on the maximum !!

Chris the Carpenter's picture

Bingo, perfect, perfect. This is why we test things by themselves before we try to put together a big project. Getting this pot to work will be important when added to a bigger project.

Ok, I would assume this is probably just a "messy" set-up. This feels like a loose wire rattling around in a breadboard to me. I can also assume the pot itself is a pretty cheap one (nothing against you, they are all cheap). 

I would reconnect everything using fresh holes in your breadboard --Breadboard contacts can get spread out when larger parts are used. When a smaller one goes in later, it can lead to a loose contact.

If you can, solder some jumper wires directly to the pot. 

All in all, this feels like a dirty connection somewhere, maybe some junk inside the pot. Tidy up, snug up your wires, try a different pot if you have one, see if you can get some better numbers.

6677's picture

Its an analogue device. Analogue to digital will never give 100% consistent readings, can get close though.

 

Check for broken solder joins, or If your breadboarding that everything is plugged in securely. Either one could alter the reading from a pot.

 

Otherwise what you are seeing is fairly normal