General purpose wireless modules for home automation

Thread Starter

Robin66

Joined Jan 5, 2016
252
Hi Circuiteers

Are there any recommendations for send-receive modules suitable for home automation? I'm interested in low cost, low power consumption, enough range for around the home, fast dev time. I don't need high through-put.

As an example, the first project I'm considering is a digital thermometer on my hot water cylinder transmitting the temperature back to the central hub at regular intervals eg. PIC wakes up, measures temp, uses the TX module to transmit the current temp., goes to sleep.

I looked into esp8266 but it looks a little heavy going for my needs. I found the below which looks good. Does anyone have any experience of this?

https://www.ebay.co.uk/itm/433Mhz-RF-Transmitter-Module-Receiver-Module-Alarm-Super-Regeneration-Kit/142807329396?hash=item213ffaea74:g:e-0AAOSwStdbBt~A
 

ebp

Joined Feb 8, 2018
2,332
Modules like that are generally a pretty good choice for your requirements. The transmitter uses a surface acoustic wave (SAW) resonator for good frequency accuracy. The receivers are super-regenerative type, which has its drawbacks but works quite well where the transmitted frequency is accurate. The maximum data rate isn't very high, but that isn't likely to be an issue for most home automation tasks. Be prepared for all sorts of digital garbage from the receiver between proper data packets. You'll find info on the web about approaches to coping with this.

One caveat is that commercial products will likely use the same frequency, so you may run into interference from other things you or your neighbors use. Sometimes making the message frequency somewhat random can help - say instead of exactly every 20 seconds you use 18 s one time, 21 s the next, 20 s the next, etc. Most of the commercial products I've seen always use the same message frequency, so if you use a bit of variation you are less likely to get into a situation where your thing and something else interfere with each other for a long time - which isn't too likely anyway. Other methods include transmitting each packet twice with a brief and possibly randomish delay between and comparing them at the receive end.
 

Thread Starter

Robin66

Joined Jan 5, 2016
252
Great thanks for the advice. That all sounds pretty straight-forward with a micro-controller.
 
Top