When you read the data sheet correctly you can see, that the distance between the pins is different for a AA and AAA battery holder. That`s why I was asking if somebody can recommend a holder that fits.
Not yet !
In fact, the interrupt must be short enough and fast enough to be sure to not miss the RFM69 interrupts.
The code for 8 dimmers will not be really more complicated : in fact, each time we got a zero cross, we must set a timer to zero, and then wait the good amount of milliseconds to turn on the needed outputs.
So, yes, we'll have an interrupts each 10ms (each time the wave crosses the zero, to be precise !), but I think all we have to do in the interrupt handler is set the timer to zero (or to micros() ...) and then on the main loop, wait the good amount of time for each output before setting them ON.
Seems simple on paper, perhaps it will not work on the chip....
In facts, my main concern is : will the RFM interrupt be short enough to not disturb the zero crossing interrupt ?
Although, not yet tested the RFM : do we NEED the interrupt pin ? Can't we poll frequently the RFM?
Welcome to the club!
Regarding radio's: The RFM69's with a C in the type have a smaller form factor (which is pin compatible with the predecessor RFM12B). The the 'W' and "HW' versions are larger in size and have more programmable pins (which MySensors does not use) but have exactly the same functionality within MyS.
All the footprints on the boards available in OpenHardware.io are for the 'W' and 'HW' versions so I'd go with one of these.
The 'W' uses way less power than the 'HW' which would be good the for the battery life of your nodes. Sensors powered by the grid can be 'HW', but usually, in the house a 'W' delivers enough TX power to get the message across. It might be a good idea to make your gateway with a 'HW'.
Hope this gets you a bit further. Good luck and show us your results!