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Author Topic: max length for cable, serial com. Arduino Mini, Atmega 328  (Read 762 times)
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Any one knows how long I can make the cable that I use between my arduinos?
I use the built in serial communication, TTL - level. (Tx, Rx)
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There are just too many variables that will affect the answer so you might get more constructive responses if you indicate how far apart you want them and request suggestions for suitable cable arrangements
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Any one knows how long I can make the cable that I use between my arduinos?
I use the built in serial communication, TTL - level. (Tx, Rx)

Twice half their length.


It depends on:
Baud rate
Type of wire
Environment

... none of which you're revealing.
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I dont have any requirements regarding the speed, so I can use a quite low baudrate. Very small amount of data.
The wires is just random ones. approx. 0.5mm diameter. not copper. not shielded.

Im thinking, is the limit between 0-1 meter, or is it possible to reach up to ten or even 20?
I am not asking for a precise value, but more of what you think about it?!

Im guessing that, because you asked for what wire/speed I use, that the limit is around 3, or even below?

Thanks for your time!




edit:

Now I see that I forgot to write the length I needed in my previous post..
Sorry about that!


3 meters is it.
« Last Edit: June 25, 2013, 09:04:08 am by MattiasLMR » Logged

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3 meters is nothing.

At low baud rates? Even less.
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thanks!
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If it's a very low baud rate you're looking at and you aren't too particular on received pulse shape, then you could cross the atlantic ocean with a "simple" piece of wire.  The original telegraph system worked like that and eventually filled the globe with simple data transmission circuits using low baud rates (an example of which is morse code)

See attached :  http://en.wikipedia.org/wiki/Transatlantic_telegraph_cable
« Last Edit: June 25, 2013, 02:32:54 pm by jackrae » Logged

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Except in 1859:
http://en.wikipedia.org/wiki/Solar_storm_of_1859

8^)
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If another of those occur, we'll be well and truly stuffed.
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It is a matter of 'when' not 'if'.
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For my home security system I have about 10m of "bell wire" running from the front door RFID reader to an Arduino in the roof. It runs at 9600 baud and works reliably.
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For my home security system I have about 10m of "bell wire" running from the front door RFID reader to an Arduino in the roof. It runs at 9600 baud and works reliably.
Would twisting the power and signal wires around each other (as in UTP ethernet cable) assist in making a longer run without environmental noise from 50Hz mains etc interfering so much?

Geoff
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If you were worried I would get a couple of RS485 chips and go for balanced lines.
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