This is something that’s been giving me difficulty for months now. I almost abandoned the project, but last night decided to give it another go, and thanks to the dutiful efforts and brilliance of others, I have found the solution!
The problem was that I wanted to connect an ESP 12-E to an NRF24L01 module to integrate it into an RF24 network. This would allow the 12-E to act as a bridge between my house RF24 network and the internet. But it seemed that no matter how I connected the NRF to the 12-E, they just wouldn’t communicate.
But then I came across these two pages (below), where people had figured it out! It requires the use of the hardware SPI pins on the 12-E, which also require a pull-down resistor from pin D8 on the 12-E to activate HSPI mode.
Pin connections are as follows:
CSN ---------------- D8
MOSI --------------- D7
MISO --------------- D6
SCK ---------------- D5
CE ------------------ D4
Also remember, D8 must be tied to ground via a 3-5 KOhm. The page I referenced recommends a 4.75 kOhm resisitor, but I used a 3.3 kOhm successfully. Do not connect directly to ground, use a resistor!
Then in your code, initialize the radio normally, using “RF24 wirelessSPI(2, 15);”.
While I was testing it last night, I had difficulty getting it to transmit properly at first. I had it set up to send an incrementing integer every 500 mS, but it wasn’t being properly received by the other node. I increased the interval to once every second, then it began to work perfectly and ran for about 10 hours before I unhooked it. I don’t know if it was coincidental that it started working once I changed the interval or not.
Also, I have not tested it full RF24 network functionality yet.