Hello, i was looking for a cheap solution to connect button switches, and other basic stuff to arduino, and i've found that basic phone cable is below 10$ for 100 meters, it has 4 wires and wont be an overkill for basic stuff like buttons. I'd like to operate at 5v. Pros, cons? Thank you
When you say long range, what are we talking? 5 volt signalling levels won't get you very far unless you have garden hose like wires.
Well, i was not talking about exact range, lets say 100 meters, or 50
You should definitely up your signalling levels. 5V at that range is liable to give you a great deal of grief.
What would be the maximum range for this cable with 5v then?
It's going to depend on the application. I don't think there's a simple answer to this question. But think about your arduino and TTL logic levels (I assume you're planning to interface directly). You want to read a logic 0? You'll need an input of no more than 0.8 volts, anything above that and you find yourself in a grey area. A great many unexpected things can happen with long wires. TTL is not very well suited to long wiring.
Ok, lets say its a basic button on one end, and arduino on another.
Listen - in an ideal world, you can loop a cable around the world twice and it'll work perfectly. But we don't live in one. There's no way of telling what that cable might pick up on a 100 meter run. All I'm saying is, TTL is not for long cables; you should always use some sort of line driver when you are looking for distance. If you're going to do it that way, don't be surprised if the button decides to push itself once in awhile.
Another side of using phone wiring. If you are thinking of using it outside, in the sunlight, the UV will quickly make the insulation brittle and eventually will allow the wires to touch. Even short runs will have short lives in the sunlight.
Well, twice around the world is not something that someone could use/check, but 100 meters is, thats why i'm asking. Thank you for all you answers, but the question is more about the cable, or where would be the edge between it fits and it does not.
UV, yes, anything else? Thanks
I hear you, I'm just saying there aren't any easy answers. For extremely simple things like a button (which makes for some seriously slow data), things may work out just fine. But is that really the only application you are considering? There are so many variables to consider here it's impossible to answer. Many factors come into play here. Length. Shielding. Data rate. Solid core or stranded. Twisted pair-or-not. Bends. Surrounding environment. From my point of view, it's not so much the cable that is the question. It's the signal levels and the termination.
What you intend to do, just a button, is really undemanding but there are too many imponderables. The idea of garden hose-like wiring is pretty silly, as we aren’t talking about much current, and a couple of volts dropped should not be a problem. Your local environment can be a player here, so if you really want to use phone cable, the best thing to do is suck it and see. Nobody can guarantee it won’t work.
The best reason for using phone cable is that it is already to hand. It would not be a good idea for most sensors.
The cable of choice for long runs is CAT5. It offers greater c.s.a., it’s shielded, and it’s still pretty cheap.
Phone cable is also invariably twisted-pair so current signals like industrial 4-20mA or RS485 will work quite well on that cable, easily as far as a kilometer. Voltage-based signals like TTL are not suitable for long cables.
Thank you all!
I think you gave me all info i need, and confirmed some of my ideas.
I agree on RS485, but then i need power on button side controller (is it right?). I've also check the nrf24 pa lna, and ordering from China it might be even cheaper than just to buy a single 100m cable. But my apprentice vision says that wires are better for quality and speed of signal (especially if not in open field). In a same time i have'nt seen any projects with such long wires.
Shielded CAT5 (UTP with one foil) is 30% more expensive, or CAT5 (STP with foil for each pair) is 4 times more expensive than phone cable. But i guess you have to be an expert to make all the research to see what is really better.
Yeah, you would need power for any active components on “the other end”. In the end it all boils down to what you are trying to accomplish.
Hard wiring a circuit is the reliable choice. That said, there are good alternatives these days. If mobility is a priority, you might want to go wireless.
Wireless also requires power on button side, which i was trying to avoid. 2.4 works well but only if PA+LNA, basic nrf2401l+ cant even pass 30 meters i will try 433, but in a same 3000 square meters we will have up to 20 radio sets (voice).
Plus, wireless can be affected by weather, temperature, obstacles, bullies and so much more.
My very first idea was to use arduino with PoE shields on buttons side, but its also overkill and quite expensive solution.