Is ARM the future of MySensors?

nagelc

I think the NRF5 with integrated radio will be the best solution for most home automation tasks as long as it has enough range to do a typical house without repeaters. But, I am fascinated by the "blue pill" stm32 boards -- very much like an Arduino Nano, but with modern ARM. It's a larger board, I don't know about battery operation yet, but for a powered sensor, it is easy to use, powerful, and cheap.
Thanks to @NeverDie I also have a RA-01 LoRa module on a ESP8266 running as a gateway. So many amazing technologies . . ..

It's hard to fault a ProMini with an NRF2 or RMF69. Those networks will probably always be reporting temperature and motion in my house. But I am always excited to think about the capabilities of these new technologies, particularly more memory. For me, it is a hobby and I can afford to try things just for fun and to learn about them, but even I must settle on a technology so I can get back to making interesting sensors and actuators.

I keep looking for HopeRF to come out with an ARM-RFM combo to compete with NRF5, but they do not seem to be going that direction. Right now, I would bet on NRF5 as the best technology going forward.

DavidZH

I certainly can see the appeal for the NRF5 series, which wil work perfect in areas with detached and terraced houses. But in Urban areas with lots of high rises the 2.4GHz band is a bit congested. So there another band will work much better.
In that regard I fully agree with @nagelc to pray to your deity of choice for HopeRF to start integrating an MCU with the RFM, or Nordic to start exploring a different part of the ether.
I have not set foot in the 'large' part of the MCU spectrum, but I have a Feather M0 in the house which will be the center of my new experiments.

NeverDie

@davidzh said in Is ARM the future of MySensors?:

to pray to your deity of choice for HopeRF to start integrating an MCU with the RFM

Even doing that doesn't give you all the benefits that tighter integration onto one chip gives you. For instance, on the nRF5:

You don't communicate over SPI. Instead, the radio can share pointers directly to memory using easyDMA. Much faster, which translates also to lower power consumption.
You can manage the radio and do other tasks (albeit in a limited way) while the MCU sleeps using the Programmable peripheral interconnect (PPI). This is maybe something that's hard to appreciate until you've tried it, but I'm sold on it and would sorely miss it if forced to return to a non-integrated MCU and radio, even if they were co-located together on the same module.

Nca78

@davidzh said in Is ARM the future of MySensors?:

But in Urban areas with lots of high rises the 2.4GHz band is a bit congested.

That's my case , there are 350 appartments in my building alone and my nrf24 network runs well, while my old 433MHz system regularly miss messages, that's why it will soon be replaced.

NeverDie

@nca78 said in Is ARM the future of MySensors?:

@davidzh said in Is ARM the future of MySensors?:

But in Urban areas with lots of high rises the 2.4GHz band is a bit congested.

That's my case , there are 350 appartments in my building alone and my nrf24 network runs well, while my old 433MHz system regularly miss messages, that's why it will soon be replaced.

LoRa isn't as much affected by interference since it's spread spectrum.

alowhum

So is anyone thinking they will use the encryption features on a normal Arduino? Or is it, as I was thinking, that if you want to use encryption you'll have to upgrade?

gohan

Simple encryption runs fine since it is mainly done by the radio chip

Anticimex

@alowhum if you only enable encryption (not signing) you can fit more into an atmga328p. Also, if you use a rfm69 radio, encryption is hw backed, so it require less flash space (thus potentially allow you to also fit signing).
Furthermore, using a atsha204a means signing also take less of flash since some of the algorithms are hw backed.

NeverDie

Well, regarding the OP, I think I read somewhere that development would largely move to ARM, and that at some point it would stop on the atmega. Not sure that I'm recalling it correctly though. Is it true?

alowhum

@anticimex: interesting.

This is my use case: all I want is that I put a password at the top of all my arduino files, and then my neighbours won't be able to receive my data because they don't have the password. That's encryption, right? At the moment anyone can pick up the values that my sensors are sending out into the city. And that's kinda creepy.

gohan

@alowhum I bet there are hundreds of people interested in your house temperature :sweat_smile:
Btw, yes that is encryption

Anticimex

@alowhum the simple password option is the simplest way of enabling security. At the same time it is the most expensive as it does not require personalization and therefore is pure software based (except for rfm69 encryption). So you need to trade simplicity for code size.
That said, once you have figured out personalization (and there is plenty documentation on the matter) it can easily be repeated, as long as you keep the sketch used to program the personalization data.

Anticimex

@alowhum also, the simple password option enable both signing and encryption so it takes up a lot of memory. If encryption is the only thing you want, just personalize the devices with an AES key and enable encryption only. It is not that good (fixed iv) and easily crackable by someone who has an idea about AES but it at least obfuscate your messages fairly well. Combined with signing it is better, but, again, that costs memory.

alowhum

@anticimex Hmm, I didn't realise that. Could it be an idea to create a MY_ENCRYPTION_SIMPLE_PASSWD feature as well, without the signing? Would that fit the "opportunistic curious neighbour" scenario?

Anticimex

@alowhum give personalization a shot. Since you use the simple flag, you are already on the development branch, so you have a simplified personalization flow. It is documented in doxygen (see the pinned signing post for a link)

alowhum

@gohan said in Is ARM the future of MySensors?:

@alowhum I bet there are hundreds of people interested in your house temperature :sweat_smile:
Btw, yes that is encryption

Actually, just my temperature would already indicate

Whether I am home or not. "He'll never know we took the jewelry".
if I go on holidays a lot. "How is he paying for all that".
Whether I am feeling ill (set it a bit higher). "Got a fever last week? Or did your grandma visit"?
If I am environmentally conscious. Something I don't want to talk about at the neighbourhood BBQ..
Etc.

Now add to that my other sensors.
Now add to that all the actuators (yikes!).

NeverDie

Don't your neighbors have better things to do?

gohan

@neverdie I was about to say the same... it must be a very boring town :D

ghiglie

Well, last week I couldn't realize how my garage temp was so high.... I noticed my neighboor started autoproducing some sensors too... :D So it's time for signing/encryption.

dakipro

@nca78 said in Is ARM the future of MySensors?:

there are 350 appartments in my building alone and my nrf24 network runs well

If nrf24 working on same/similar frequency as wifi, is it not being disturbed by other wifi networks? (I guess that in 350 apartments there are a minimum of 350 wifi networks).
I never quite understood how exactly nrf24 and wifi go along.

Is ARM the future of MySensors?

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