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Arduino Wireless Master to multiple Slaves.

Thread starter #1
Hi all,

This is my first post in this forum, as I'm mainly involved in Microcontrollers (PICS etc.) ... I have a requirement where I want to use an Arduino as a front end master controllers to some sort of a wireless duplex network, 'talking to' a series of battery powered mobile slaves units that are able to identify their own 'address' and respond accordingly.
I have looked at the HC-05 and HC-06 Bluetooth modules, but get the impression that these only have a range of about 20 or so feet, and operate in a 'point to point' configuration, so feel that this is not really suitable for my needs.
I already use extensive RS485 protocols on 'wired' systems with a single Master and around 90 odd slaves using a 'home brew' communications protocol, in effect, what I want to do us replace the 'cables' from the Master to all the Slaves with a wireless connection.
The 'System' will be totally self contained, with no connection to a PC or 'Human Interface' etc, (except for setting up, testing, debugging etc.) and don't really want to use a 'router' as a 'hub' unless absolutely necessary.
With the 'wired' system, it is extremely 'secure' as far as external influences are concerned, and would like the wireless system to have a similar secure integrity, although its not 'dangerous, private, critical' in any way, so if something does 'hit' the system, it won't matter, it will just reject it (in software) and re-try etc.
The range of communication will be no more than around 50 feet, 'line of sight' and is an 'indoor' environment ... I did think about using Infra Red Communications, but feel this would be too unreliable for 'line of sight' with moving items, such as that of 'radio control cars, boats, planes' etc. which occasionally do go 'out of sight' for short periods of time.
I've only just starting thinking / researching this 'project' so ANY help, advice, suggestions would be greatly appreciated. ....



Well-Known Member
Most Helpful Member
Thread starter #3
Thanks for your quick response MikeMI, it is appreciated,
I read with interest your 'links' and it has clarified a few points that I did not appreciate and/or understand.
I have 'ordered' from eBay an HC-05 and 4 x HC-06's, BlueTooth modules just to have a play with, although these operate in 'point to point' and 'in effect' would be a single connection to just one of the remote devices, I was thinking I could 'manipulate' the slave addresses to 'pair' to as and when required from within the master.
It's only a concept at the moment, and something to play with to see if it is feasible, I can't see any reason why it should not work .... But 'playing' will prove it one way or the other ...
Again, any comments or suggestions from anybody are welcome and appreciated.

Incidentally, I'm relatively new to Arduino's so I am on a bit of a learning curve, as I mainly work with Pic's and Microprocesors, and only ever programmed them at Assembler level (to achieve the speed, and reduce the code overhead compared to higher level languages like 'C' code) , so never pursued 'C' in any way at all, so I do need to get to grips with some coding in 'C' hopefully with particular relevance to Arduino's.
If anybody has any suggestions of a suitable Arduino 'C' training tutorial or book that would help me on the way, that would be great.


Active Member
The best and easy option in my opinion is to go for Xbee . These wireless modules can be configured as a wireless tree network and be networked with relative ease. These 'Xbee' modules have 100 meter range with high gain antennas. Each 'individuals' in the network or so called nodes can be individually accessed by the main node (the co coordinator). They are available as easily configurable modules. [check this link http://www.digi.com/lp/xbee] . These devices works on UART, with a simple AT command structure. Its pretty easy to configure the devices.
As for the Arduino, its facile to learn. Buy an Arduino, preferably a UNO variant and experiment. You might get surprised how easy it is. Check their main website [https://www.arduino.cc/]
Good luck with your project.
Thread starter #5
Magvitron, thanks for your quick reply, I've just had a quick look at the Xbee and a few references to it on YouTube etc. And it seem's that these may be more suitable than the other units I looked at, I'll likely get a few to have a play with (fortunately there is a reasonable development budget available precisely for this sort of checking/testing/playing)
I'll do some more research into these Xbee units and 'Google' around for info.
I already have several Arduino Pro Mini's (used on other projects) , a few Uno's R3's and have just ordered a Mega, so can have a bit of playing with various setups etc.
I have found what I think may be a reasonable tutorial, at http://tronixstuff.com/tutorials/ (at first glance)
I'll keep this thread 'posted' with my results etc. for anyone that may be interested its its outcome.
Thanks again,

I too have gone the RS485 way and am also looking into going wireless. I plan on using the Nordic nRF24L01 2.4GHz transceiver. Lots of info available for Arduino. Unfortunately with my work (currently in Iraq maintaining the control system of a very old power station) I do not have as much time on my hands to get started. Hope you have more luck?
Thread starter #7
You have been busy, I have been reading your home automation project with great interest, the PCB milling is mesmerising, but way beyond my means, I tend to design using mainly EasyPC SDT (Schematic Design Tool and PCB Design software from Number One Systems) or KiCad and then send the Gerber files off to China (A good 'cheap' supplier is ITead ... (https://www.itead.cc/open-pcb/pcb-prototyping.html).
I am going to have a look at the nRF24L01+ device and its relevant Arduino code etc. (Thanks for allowing your code to be available on your GitHub page as well, makes interesting reading .... I can even understand some of it !), I'll breadboard a few tests over the coming weeks and see if I can fulfil my requirement.
I may look into this 'GitHub' system, its the first time I've come across it (I said I was a novice at this !), and see if its possible for me to generate a page of my own for my project(s) progress etc.
Sounds like your a bit busy there in Iraq, fortunately, I'm retired now, so 'work' does not interrupt my hobby endeavours.
Back to the research and drawing board, at least its keeping be occupied ....

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