RF or WiFi for remote lighting?

Question

I don't know much about electronics. I'm a developer/Linux admin. I have a Raspberry Pi2 that I may run on Raspbian or Ubuntu Core. I'd like to control my lights via the Pi.

My questions is: is RF or WiFi the best option for this?

For RF, the way I see it, I can write some Python code to work with a Transceiver like this to control the lighting device.

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For WiFi as well, I'd write some Python code to interact with the lighting device.

I imagine my device would be an RF or WiFi relay switch. I'd conceal inside my wall switch. I'd be able to remotely turn this on and off. I'd also need to be able to manually override (i.e. turn the wall switch on and off using my hand). I'd get an electrician to install this but I'd like to know if this plan is feasible and, of course, whether RF or WiFi is better.

Thanks!

:EDIT: There are the two single channel RF relays I'm looking at right now:

• 1 Channel 12V Latching Relay Module with Touch Bistable Switch MCU Control
• 5V 1/2/4/8 Channel Relay Board Module for Arduino Raspberry Pi ARM AVR DSP PIC

I'm not sure which one is better or if RF is even the best choice yet.

Answer 1

For start, WiFi is RF (radio frequency), though it implies a whole stack of networking abstractions built on top of the RF communications.

I would not recommend using those transceivers because you will need to implement a whole pile of functionality yourself, i.e. packet framing, acknowledgements, error detection, etc, etc. That is a very large hurdle to climb, given the questions you are currently asking.

Those relay boards you have linked are NOT RF in any way. They take low voltage electrical inputs, isolate them and use them to switch a relay. You could happily wire those relay boards to the Pi's GPIO outputs, but it means that the relays would be co-located with the Pi. If you were using a Pi Zero with a USB WiFi adapter, that would be a very reasonable approach.

If you want a wireless connection between a Pi and some relays then you will need both a wireless link and a small microcontroller at the far end to interface between the wireless device and the relays.

I suggest that you look first at the ESP8266, which gives you a 32-bit microcontroller with built-in WiFi, a small number of GPIO pins and a relatively-easy (arduino-compatible) means of programming it. It would be capable of receiving commands over WiFi from a Pi or a phone or whatever and activating those relays. Edit: this is basically like buying a Pi Zero with built-in WiFi except that it's much smaller, lower power, doesn't run linux and you have to write a bunch of C to control it.

If you don't want to use WiFi, then look up an nRF24L01+. They're a couple dollars each, relatively-easily interfaced to a Pi and/or microcontroller, and they handle all the packet-radio hassles for you. You will need to use a microcontroller on the receiving end to interface between the radio and the relays.

The third option is that some cheap wireless switches have had their protocols reverse-engineered and can be controlled using chips like the nRF24L01. That would mean you can buy safe, commercial remote relays, ditch the remote control and start controlling them from your Pi with the appropriate radio interface.

Answer 2

For simplicities sake, stick to RF. Most remote controllers in home are used with RF, so it's good to stick with a commonly used setup. For the Wifi solution, you would have to setup a Wifi Direct client on the raspi, which is feasible but much more complicated, much more expensive and uses up a lot more of your time. You have to buy special ICs for this and then configure the connection so they link up. In terms of cost and and practicality, I would go with RF transmitters and receivers.

EDIT: I would've suggested going with the RF (Infrared) LEDs from Adafruit. They already have a tutorial setup and most of the process is already laid out.