What is the simplest communication scheme you used?

[cyberblak]

Hi,

The subject says it all... Anyone has an idea on how to get simple commands between 4-5 systems?

It should be reliable, use 2 wires at most, and be able to travel a couple of hundred feet.

Thanks,

cyberblak

 

[gharuda]

hello,

wireless is the best option for long distance , it is quit easy use a Fm transmitter,
and fm receiver is quit compact and easily avaible,

 

[xischaune]

I would recommend microcontroller based serial communication...i have used it with a SHAPER IC CD-4093B and it easily works upto 1500-2000 feet easily

 

[dkace]

Can we cover the wirelles again?
I have a system which communicates with several small units all using μCs.
I want to change the cables and use wirelles. Can you give me a rugh plan of the wirelless system? In blocks and main chips I have to use?
Thanks
D.

 

[cyberblak]

In my case wireless isn't a option since the product needs to be ultra low-cost...

Too bad, I'd have had a lot of fun doing it

 

[Mike K8LH]

Are you talking about one "master" and 4 or 5 "slaves" (Master initiates and controls all communications)?

Mike

 

[cyberblak]

All options are open...

In fact the system's topology would lead to this option: there's one master and 4-5 peripherals. The peripherals only reports an event from time to time (the push of a button, per example), thus I don't see the master querying the slaves all the time.

thanks,

cyberblak

 

[Mike K8LH]

How about serial over RS485 using RJ14 or RJ45 modular connectors? RS485 is a relatively noise immune long distance half-duplex topology and you could even include power on the connectors to power the slave devices.

 

[Beeblebrox]

I'd vote for a RS-485 line. I made something similar for communication among 3 (up to 12) units under noisy conditions.
I used PIC MCUs with MAX481 transceivers.

 

[cyberblak]

Hi,

RS485 was my favorite option, actually. Using modular connectors is a good idea, it's far more convenient than fiddling with mini-terminal-blocks.

Ever had reflection problems with rs485 when you are not on a bus topology?

Thanks,

cyberblak

 

[artem]

There is no problem with transmission if you are njt going to power these 5 system from same line . If it is - rs485 wont be your choice - go for X10 over power line or something similar and simple.

Yet your requirements are not clear enoguh - is this master slave or independent nodes . If latter - will need bus arbitrer based or token ring alike or random access with collision handling algorithms (X10 does allow that) protocols.

 

[dkace]

I don't get it
if he has power RS485 won't do the job?
why?
D.

 

[cyberblak]

I'm wondering that, too...

 

[Mike K8LH]

Hi,

RS485 was my favorite option, actually. Using modular connectors is a good idea, it's far more convenient than fiddling with mini-terminal-blocks.

Ever had reflection problems with rs485 when you are not on a bus topology?

Thanks,

cyberblak

The company I used to work for had some small bar code reader terminals installed in the Labs and connected in an RS485 'star' to a multi-port 'master' controller. They worked fine. Distance from the 'master' was probably about 80 meters. I suspect each of the terminals had RS485 termination.

Take care. Regards, Mike

 

[masud58]

also topics here

 

[artem]

I don't get it
if he has power RS485 won't do the job?
why?
D.

I ment - if you have few devices with rs485 interface and need to power them from one place - you will need at least 4 wires not 2 (according to requirements in first post), but that is only for case if you dont have power a location of each device .
Yet it is preferred to have common ground connection between rs485 devices - that means 3 wires.

If above is not the case - rs485 will be OK.

 

[cyberblak]

Hi,

I've got 2 wires for the com, 2 for the power.

No problem there.

Thanks,

cyberblak