I wanted to remotely control some simple on/off things such as lamps, tv's etc. using remotely controlled relays. I first started experimenting with the good old NRF24L01+ chips. After much testing it seemed that these were not 100% reliable. This could entirely be due to the cheap Chinese modules that are strongly rumored to be using knock-off chips. People suggest adding capacitors near the +/- pins on the module to smooth out the power. After a LOT of testing I could never get these things working as reliably as I wanted. They even seemed to just lock-up after a period of time in an unpredictable manner.
Then I switched to using ESP8266 WiFi chips. These were pretty much completely robust and I havent had any unpredictable or random results in about a year since deploying them.
Here are some images of both types of boards I made. One uses an ATMEGA328P microcontroller with a NRF24L01 module. The other is a board with an ESP12E module on it.
Both types of boards are designed to piggyback on one of these dirt cheap and common dual relay boards:
One of the many iterations of using ATMEGA328P and NRF24L01. Theres still a bunch of flux on this one and also the NRF24L01 module has some scorch marks near it and looking generally beat up due to having to desolder it many times to swap out the modules! :)
Piggybacked to a 2 relay board:
Now here is the version I made with ESP8266.
Front of board before assembly:
Piggybacked to a relay module:
Another iteration of the ESP8266 based boards.