Go Down

Topic: max length for cable, serial com. Arduino Mini, Atmega 328 (Read 905 times) previous topic - next topic

MattiasLMR

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)

jackrae

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

fungus


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.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

MattiasLMR

#3
Jun 25, 2013, 04:02 pm Last Edit: Jun 25, 2013, 04:04 pm by MattiasLMR Reason: 1
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.

fungus

3 meters is nothing.

At low baud rates? Even less.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)


jackrae

#6
Jun 25, 2013, 09:14 pm Last Edit: Jun 25, 2013, 09:32 pm by jackrae Reason: 1
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

KeithRB

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

8^)

jackrae

If another of those occur, we'll be well and truly stuffed.

KeithRB


Nick Gammon

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.
http://www.gammon.com.au/electronics

strykeroz


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
"There is no problem so bad you can't make it worse"
- retired astronaut Chris Hadfield

Nick Gammon

If you were worried I would get a couple of RS485 chips and go for balanced lines.
http://www.gammon.com.au/electronics

Go Up