Second setup, choosing a radio

[projectMarvin]

Hello everyone :)

I'm about to start my second MySensors setup. First one was a few years ago but I put it on hold and decided to focus on getting a stable setup in OpenHAB with some commercial sensors.
Now I'm back looking to expand on the sensor front and I think MySensors is the best option.

But what radio is the best choice today?
I don't have anything left of my old setup so I'm starting fresh.
After digging through the forum I have come up with the following setup and would really appreciate some feedback.

MQTT GW: Amplified nRF52840
Nodes: nRF52840 or nRF52832

The plan is to mostly have battery powered nodes.
Are these good selections or are there any better options that I have missed?

My plan is to initially use a dev kit and a usb dongle to get started and then make custom sensor boards connecting to and powering the nRF52s.

Any and all input is highly appreciated :smile:

[projectMarvin]

Reading more it seems like OTA for these devices is not supported yet.
@NeverDie @scalz Did you ever get OTA working on these boards?

[Sasquatch]

I found that 2.4 GHz is too noisy for stable operation in area, had problems with range and missing packets. Radios worked fine, 80-90 meters in open field, 2 meters indoors across one room !!! but i can see 20+ WIFI networks within reach.
Long story short: check your environment before you buy many radio modules.

I'm currently in finishing stages of ultimate low power node - 5+ years on single AA(LITHIUM) battery with one minute update/report interval, based on RFM69+atmega328p.

If you really need/wand OTA then nrf24 or rfm69/rfm95 is the way to go. Possibly gateway could be nRF52840 and nodes nrf24, not 100% sure, but should be compatible.

[projectMarvin]

@Sasquatch Cool thanks!

I'm really conflicted about what to choose.
The nRF52s run cortex M4s, which I have worked a lot with.
But I want OTA because I don't want to run around and manually upgrade each node. Then I will try to avoid it and end up running a lot of versions of each node.
The rfm95 is a viable option, slightly more expensive but very good range. But as I understood it they are not very suitable for battery powered actuators, not sure why though.

[NeverDie]

@projectMarvin said in Second setup, choosing a radio:

Reading more it seems like OTA for these devices is not supported yet.
@NeverDie @scalz Did you ever get OTA working on these boards?

Nope, not in C, but I did achieve OTA using micropython, uLisp, and Forth, because those 3 are interpreted. However, there may be more information available now on how to do OTA for it in C than there was when I last checked. With C it would require a wireless bootloader. Perhaps one or more of the nRF52 RTOS's would have it by now. It might (?) possibly even be a part of platform.io by now, though I'm doubtful.

[Sasquatch]

@projectMarvin
nrf52 rx current is ~5mA - 480h on 2400mAh battery
rfm69 rx current is 16mA - 150h same battery

Both times rather pathetic, you never run battery powered node in constant rx mode.
If you power down radio as often and for as long as possible you can get 5+ years out of both radios on single AA lithium thionyle battery and keep data flowing every minute or so. I suspect that on Nrf it might need less programming acrobacy.

As for OTA, you should need to update your firmware only when security patches come out for library, once a year maybe?
pulled from nrf52840 datasheet:

The non-volatile memory controller (NVMC) is used for writing and erasing of the internal flash memory
and the UICR (user information configuration registers).
(...)
The CPU must be halted before initiating a NVMC operation from the debug system.

It looks to me that self programming is not possible. BUT i have never worked with tem (or any other M4) so what do i know ;)

[berkseo]

@projectMarvin Most recently, I tried updating mysensors nodes on nrf52840 via nRF Conect (BLE). Incredibly fast.

[NeverDie]

@berkseo said in Second setup, choosing a radio:

@projectMarvin Most recently, I tried updating mysensors nodes on nrf52840 via nRF Conect (BLE). Incredibly fast.

If you have step-by-step instructions on exactly how to do that, it would help just about everybody.

[NeverDie]

It's a timely topic, as Nordic just 1 month ago appears to have published info on how to do OTA using their development kit: https://devzone.nordicsemi.com/nordic/short-range-guides/b/mesh-networks/posts/thread-tutorial-practical-guide-for-device-upgrade-ota

Unfortunately, it seems like a different world entirely from the Sanjeev code, which doesn't utilize the Nordic Bluetooth devkit.

I'm moderately hopeful that Adafruit may one day release a wireless bootloader that's more compatible with the Sanjeev code. However, there's a risk Adafruit would make it for CircuitPython instead.

[NeverDie]

It looks as though ARM MBED has FOTA working for the nRF51822:
https://os.mbed.com/teams/Bluetooth-Low-Energy/wiki/Firmware-Over-the-Air-FOTA-Updates

ARM MBED is the rtos that Arduino chose for its nRF52840 "nano" product offerings.

[berkseo]

@NeverDie This is not a very convenient update process, although it is incredibly fast. You need to download the archive with the firmware to your phone. In the nRF Conect app, you will connect to a mysensors device that has previously been switched to bootloader mode (secure bootloader). Next, you need to choose the archive with the firmware and accept the download. This is a research interest rather than a working option :)

[projectMarvin]

@NeverDie How about this?
https://github.com/adafruit/Adafruit_nRF52_Bootloader
based on nrf5 sdk v11 though, current version is 17.

I had almost given up on mysensors and was considering the nrf52840 with openthread and mqtt-sn since nordic has working examples for that all the way from a mostly sleeping nrf52840 to an mqtt-sn - mqtt bridge.
I really like the nrf52840 and I want OTA since I know I will never leave my nodes alone and stop updating their codes :upside_down_face:
LoRa is problematic since I want something that is legal in both Sweden and China.

But mbed os shows promise and if the nano ble runs mbed on an nrf52840 then that should open a lot of doors.
Maybe this project will finally push me to adopt an RTOS :grin:

This sounds promising.
https://infocenter.nordicsemi.com/index.jsp?topic=%2Fsdk_nrf5_v17.0.0%2Fexamples_bootloader.html&cp=7_1_4_4

[NeverDie]

@projectMarvin said in Second setup, choosing a radio:

Looking at:

https://github.com/adafruit/Adafruit_nRF52_Bootloader

it does look as though there is a possible OTA mechanism:

DFU = LOW and FRST = LOW: Enter bootloader with OTA, to upgrade with a mobile application such as Nordic nrfConnect/Toolbox

but if it requies a mobile phone application... it sounds a bit inconvenient, similar to what berkseo was alluding to. Nordic's software efforts always seem to assume Bluetooth, which is frustrating, because the hardware itself obviously doesn't have to rely on Bluetooth per se.

However, at the bottom it does seem to give you the option of crafting your own bootloader, and so that might be a way to do it right:

How to compile and build

You should only continue if you are looking to develop bootloader for your own. You must have have a J-Link available to "unbrick" your device.

I get the impression amazon's FreeRTOS may (?) also offer a way to FOTA update an nRF52840.

I haven't looked into Thread, but the nRF52840 supposedly supports Thread, and maybe (?) by now Thread is mature enough to have FOTA.

[NeverDie]

From what I gather Particle had a FOTA for their nrf52840 modules, but they ruined it by making it a monthly paid subscription service. Too bad.

[projectMarvin]

@NeverDie Here is a nordic fota over thread example.
https://infocenter.nordicsemi.com/index.jsp?topic=%2Fsdk_tz_v4.1.0%2Fthread_example_dfu.html&cp=7_3_2_10_4_0
They also support using a dongle or DK with a raspberry as a border router.

Nordics documentation is fairly extensive and quite easy to search, I like it :)
The nrf52840 DK is kind of the standard example hardware for openthread so they have plenty of examples.

[projectMarvin]

@NeverDie I read something about that Particle discontinued their BLE mesh boards :/

[NeverDie]

@projectMarvin said in Second setup, choosing a radio:

@NeverDie I read something about that Particle discontinued their BLE mesh boards :/

At least in part. Hackaday says Particle discontinued their Xenons.

[projectMarvin]

@NeverDie said in Second setup, choosing a radio:

@projectMarvin said in Second setup, choosing a radio:

@NeverDie I read something about that Particle discontinued their BLE mesh boards :/

At least in part. Hackaday says Particle discontinued their Xenons.

https://blog.particle.io/mesh-deprecation/
:/

[scalz]

@projectMarvin
indeed nrf52 + mysensors fota is not officially supported.
When I tried fota, I used nordic/Adafruit (secure) bootloader and derived it (because we used adafruit core + mysensors).
That was a while ago.. but actually I prefer and need subghz.
Unfortunately I'm working on others fun projects so I don't have time to work on nrf5 for the moment.

Sure using mobile app for fota is not convenient. better code a server-side app, micro service, for this task.

[projectMarvin]

So after spending some time reading on the forum I have kind of shifted toward rfm69 with a sensebender ethernet mqtt gateway.
However this comes with new concerns.
The only rfm69 frequency I can use is 433 MHz, which means huge antennas. Even coiled they are pretty big.
Searching Taobao (chinese aliexpress) the rfm69 modules are quite uncommon and so I'm worried that they are already a bit aged.
Also the majority of the ones listed are the C version with a different pinout than the version used by sensebender.
The sensebender gateway is aging, it 5 years old with the last update 3 years ago.
This is not negative, I'm just wondering if it's still a good gw for a new system or will it soon be considered old and lacking?

I'm not sure what the development plan is for mysensors, will we keep using nrf24 and rfm forever or is there any plan to shift towards something newer?