For those of you having difficulties making the Feather work with MySensors, please note that Adafruit doesn't use the standard wiring.
In order to make it work, right at the top of your sketch, before loading the libraries, you should add this:
#define MY_RF69_SPI_CS 8
#define MY_RF69_IRQ_PIN 7
#define MY_RF69_IRQ_NUM 4
@mfalkvidd Thank you for pointing me to those resources, I finally got them working.
@scalz Absolutely awesome work 
Here's a full sketch example using the Si7021 Temp/RH sensor:
#define MY_NODE_ID 2
#define MY_DEBUG
#define MY_RADIO_RFM69
#define MY_RFM69_FREQUENCY RFM69_433MHZ
#define MY_IS_RFM69HW
#define MY_RFM69_NETWORKID 100
#include <MySensors.h>
#include <SPI.h>
#include <Wire.h>
#include "Adafruit_Si7021.h"
unsigned long SLEEP_TIME = 1000;
Adafruit_Si7021 sensor = Adafruit_Si7021();
MyMessage msgTemp(1, V_TEMP);
MyMessage msgRh(2, V_HUM);
MyMessage msgRSSI(3,V_VAR5);
float temp;
float rh;
boolean requestACK = false;
int16_t rssiVal
char rssiStr[10];
void setup()
{
delay(100);
sendSketchInfo("Temperature/RH Sensor N2 RFM69", "1.1");
sensor.begin();
present(1, S_TEMP);
present(2, S_HUM);
}
void loop() {
rssiVal = transportGetRSSI();
rh = sensor.readHumidity();
temp = sensor.readTemperature();
snprintf(rssiStr,10,"rssi: %d%",rssiVal);
send(msgTemp.set(temp,2));
send(msgRh.set(rh,2));
send(msgRSSI.set(rssiStr));
sleep(SLEEP_TIME);
}
However, please note that this only works on:
https://github.com/scalz/Mysensors/tree/rfm69_update2
and
http://forum.mycontroller.org/topic/58/download-snapshot-build
Just drop a reply here and I will happily assist you using the above versions until they will be fully commited.
@scalz said:
@mihai-aldea
that's why it's always better to tell which hardware you're using, and logs. If i knew you were using 5v logic, i would have told you it couldn't work, and save timeAbout promiscuous mode, you can think about it as a sniffer mode.
Great to hear you finally found your answer
Yeah, I know I was a bit of a jackass for not reverting back whatever I was doing and provide you with logs from the MySensors lib. But I used lots of libs, some of them with various tweaks, the test setup was bit complicated and I knew that whatever logs I could see during the initial stages were not very helpful.
And speaking of helpful logs. I would've loved to see more verbose logs. Is there a way to increase the verbosity level?
As for the promisc mode, I know very well that that is, is just that it seemed strange how is it that the node ID's were all messed up.
I believe this one is on me. It wasn't clear to me that MySensors is actually wrapper of the original LowPowerLab's RFM69 lib and you can't mix #define's from MySensors and the embedded RFM69 driver.
MySensors is really plug&play if you're using the NRF24L01+ modules, follow the guides, upload the sketches and fire up the gateway, but if you want to use RFM69, I at least, needed some serious trial and error.
Maybe it's just my hectic style of trying new setups, or maybe because I found no concise guide on how to switch from RF24 to RFM69 or maybe something in between 
@mfalkvidd I will definitely do that. I'll tinker with them for a while just to be confortable with stating the facts and I will compile such a guide. It'll take me no more than a couple of days.
No need to stick to the expensive Raspberry Pi board. MyCotroller runs perfect on my 1GB RAM quad core Orange Pi PC ($15) and I see no reason it wouldn't work on the 512MB RAM quad core, with ethernet and WLAN already on board Orange Pi Zero ($9), which can be purchased in quantities of more than one per household and, shockingly, is actually available... 
Nano Pi also manufactures great boards but they tend cost double than OPi, actually getting close to the Raspberry Pi's price tag.
The only difficulty I had with deploying MyController on these boards was installing Java 1.8 which isn't currently available in the apt repos.
I'm in no way affiliated with any producer, only a happy user of Orange Pi & Nano Pi, powered by the super polished Armbian.
This is perfectly understandable but I merely wanted to give a raw input on the feature status.
I consider the RSSI values to be paramount when testing MySensors along with new hardware (antennas, wall penetration, registry tweaks etc.) as the simple online/offline node status would not help very much with these scenarios. That's why for the time being I will stick to scalz's rfm69_update2.
@Christoph-Blank said:
well - the blog post I used for the wiring missed the detail that the RFM69 does not seem to be 5V tolerant (inputs).
Can anyone tell me:
a) if it is damaged if the inputs had 5V
b) how I can adjust the levels, can I do this with resistors or do I need more?
I made the same mistake, while connecting the modules VIN pin to the Arduino's 3.3V rail, I failed to read that the RFM69's pins aren't 5V tolerant. After I figured out how to make another pair of RFM69 modules work together, this time at the correct voltage, I tried the first to if they were fried. They weren't. As soon as I connected them to a 3.3V Arduino they worked like a charm. So it's very likely that yours are fine to.
As for the correct wiring, some are using voltage dividers to lower the signal pins voltage down to 3.3V. Others are using logic level converters. Me, I was lucky engough to have a couple of chinese 3.3V Arduino Pro Mini boards ordered a long time ago and never used since. For minimal clutter, I'd suggest using the same setup. The cheapest 3.3V options are the Arduino Pro Mini (my model) but you'll also need some USB to TTL dongles (the ones having a DTR pin) to program them. Or you may use something like:
http://www.ebay.com/itm/Pro-Micro-3-3V-8M-5V-16M-atmega328-Replace-ATmega128-Arduino-Compatible-Nano-/172446438226
but notice that this one doesn't use the ATmega328 chip but ATmega32U4 and that will require these lines of code at the top of your sketches:
For MySensors 2.0
#define MY_RF69_SPI_CS 8
#define MY_RF69_IRQ_PIN 7
#define MY_RF69_IRQ_NUM 4
For MySensors 2.1.0beta (RSSI report added amongst a lot of other improvements)
#define MY_RFM69_SPI_CS 8
#define MY_RFM69_IRQ_PIN 7
#define MY_RFM69_IRQ_NUM 4
Note the slight difference between the two.
Has anyone seen these modems in action?
Besides the known 433MHz and 868MHz, now the 169MHz band is accessible. This band is regulated in Europe at a maximum of 500mW and <=10% duty cycle beacons used generally for gas meters and similar quipments.
It can output 30dBm in 433MHz and 868MHz and 27dBm in 169MHz. This allows for even greater range but it uses up to 650mA during TX.
This is a very interesting module that comes in a larger footprint than the RFM9x but has a way greater TX power and makes the 169MHz band accessible and I think that once it hits the market and the RF engineers start to tinker and build Arduino libraries for it, it will become farily popular.
The onboard temperature sensor is not a cool freebie. It's meant to be a way to check the approximate environmental temperature for the outdoor or industrial devices (not only sensor nodes) using RFM69.
The DS18B20+ is not a great sensor for the battery powered nodes. It has a huge conversion time comparing to others.
9-bit resolution | 93.75 ms | 0.5°C
10-bit resolution | 187.5 ms | 0.25°C
11-bit resolution | 375 ms | 0.125°C
12-bit resolution | 750 ms | 0.0625°C
The last column is the sensor's precision. So unless you're OK with a 0.5°C steps, the simple usage of DS18B20+ will kill your battery a lot faster.
Don't use DHT22, that one is very slow too. BME280 does have a barometric pressure sensor but it's not very fast either.
The best sensor for battery powered nodes is the the Si7021 which is rather old, but is the fastest.
Well, this makes sense. And after all, if you're smart enough to tweak the lib and bypass the restrictions, chances are you know what you're doing both with the coding and with the radio spectrum.
They're an interesting option in special use cases. Eg. I mounted a sensor on my flat building janitor's storage room. I wanted to know if she comes daily as agreed and if so, how long does it take for her to clean the staircase. The RFM69 modules didn't worked so I switched to RFM96 which struggles to get the signal through 2 floors and on the other side of the building where I placed my gateway. And this while using RFM95_BW31_25CR48SF512. It works, but if I were at the 3rd floor, I'm sure it wouldn't have worked.
Next thing I want to monitor the status of the water pumps that are in a special room beneath ground and also on the opposite side of the building. And I'm pretty sure that the RFM95 will not make it there unless directional antennas or repeaters are involved.