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Separate network for 5 Slaves 1 Master 1 server Answered

I've build a home thermostats system with PIC18F27K42 in each thermostats with LCD, for 5 rooms,
1 master in kitchen and 1 server in the basement, working on a bit-bang i2c. The server only send data to i2c at every seconds as it have a RTC (Chronodot) plus freezer and external temp sensors. The kitchen has a bigger LCD and can send data to the server to send to a dedicated or all thermostats using an ID in the data stream. I have read some docs on the net and bought a ESP32 DevKit V4 with WROOM-32D (changing later for a WROOM-32U external antenna for the downstairs server) and 6 ESP8266 ESP-01S module to include in each thermostat. My goal is to use the wifi instead of the i2c. So I'd like to have some guiding on how to achieve this. Maybe later I may use this wifi to use internet to change some settings in one or all thermostats. But for now do I really need to use the house wifi or can I use a kind of "thermostats wifi", separate from the house one, mostly for heating security. If so, how can I do that, since I'm kind of new to network and wifi. Many thanks to all.


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1 year ago

Thanks to all for your help, hoping that can be useful to others.

slient person
slient person

1 year ago

okay this is really intresting so Im trying to make my rc car go really fast without having to buy certain Parts online or in store


1 year ago

Nice project indeed....
My days of developing electronics are slowly reaching the end of their glory but maybe this is a good thing...
Wireless is the way to go for sure these days but in many cases people forget about the old school options.
You know why the oldest computer joke in the world is still so valid?
Because it came from a real background and still does ;)
"Why do we need a computer?" "To solve problems we wouldn't have without it!" ;)

Wireless tech is no different here.
Because we can we use it, even if we first need to find a use for it and develop useful options LOL
Back to your problem...
Wifi at home is good as long as you have good covereage and little interference.
Don't know about your area but I already struggle find a free channel for my Wifi :(
If a wired solution is out of question, how about semi wired?
POL systems are old school but usually stll work fine.
Power over Line enable to use your homes power outlets for data transmissions, like still used for so calld "Wifi extenders" that simply send the data over your mains lines in the house.
But I think for your application LORAD systems would be a really great alternative.
Low power consumption, enough free channels available and no worries with protocols as the stuff is developed to cater for small data packs.
In a low distance environment like home you should even get away with just circuit board antennas instead of external ones, keeping a small footprint on the overall size.
In thier most basic form Lowrad system have a receiver and one or several transmitters.
All can happily run on battery power for months.
The receivers are available for all sorts of universal and dedicated applications.
Like taking analog data or just digital, while compressed data is being sent to the receiver.
The user only needs to worry about configuring the transmission interval.
Some modules even allow for data storage and compression.
Means the module collects data at fixed intervals but only sends out one transmission burst once a day or so.

As for Wifi only:
If the system you have allows for a dedicate host to create a WiFi system that is fully independent than go for it.
Otherwise I would actually prefer to set up a cheap router for just this purpose in a central enough location.
Even inside a wooden cabinet a half decent D-Link router with external antennas would provide near perfect coverage for all your thermostat needs.
Eliminates the issue of weak connections for example.
Plus you can make all sorts of adjustments without having to worry about the security of your internet providing router.
Linking the two if required is enough anyway.
Please keep in mind that quite often antenna placement is more important than antenna gain !
Especially considering the short wavelenghts for the 2.4 or even 5GHz Wifi bands.
Have a look all all those websites explaining antenna gain and placement on your car for UHF or CB system to get a quick and good understand of what I mean - there is even nice videos on Youtube about it.
If you do not run the system on battery power you still might want to check the option for using your house's power lines to cater for your data though.