Everything nRF52840

NeverDie

After waiting almost a year for the dust to clear, it seems that there are now roughly two leading platforms at the moment that either have or may get good software support:

The Adafruit nRF52840 feather: https://www.adafruit.com/product/4062
which Adafruit either has or is making Arduino compatible.
Possibly the Arduino Nano 33 BLE: https://store.arduino.cc/usa/nano-33-ble
and/or https://store.arduino.cc/usa/nano-33-ble-sense
for which, ironically, Arduino has chosen to adopt using mbed as the core software techology.

In other words, it appears that Adafruit has become more Arduino than Arduino!

There are also some "particle" boards that are hybrids:
https://www.cnx-software.com/2018/02/14/particle-unveils-three-nrf52840-bluetooth-5-boards-argon-wifi-boron-lte-and-xenon-particle-mesh-technology/
I had thought these would necessarily be more expensive, but right now the Xenon board is selling at $15, which is almost half the price of either the Adafruit or the Arduino boards:
https://www.amazon.com/s?k=particle+xenon&i=electronics&ref=nb_sb_noss_1
Are the particles easy to program and perform OTA updates? I have no experience with them. They're pushing a subscription service if you have more than ten or so of them, so I suppose the true cost could be higher if you go "all in" on them. On the other hand, if you happen to want/need whatever their cloud service is, at least you'd be getting some kind of value for your subscription money. I suspect that, at the moment, it may be the easier to do OTA updates with particle than the first two, if only because it needs to be good if they are to justify their service fee. Their Photon board (which is a wi-fi only device) has gotten mostly favorable reviews on Amazon. On Photon the subscription fee doesn't kick in until you have more than 100 photons, which sounds a lot less confining the the 10+ units of Argon or Xenon. Unfortunately, it sounds as though it's not low power enough for battery powered nodes: https://www.youtube.com/watch?v=68N67ZVxTZ0 A 7.5ma deep sleep sounds stupidly high to me. What were they thinking?

In summary, the Adafruit nodes sound best to me at this point in time. The Arduino nodes might catch up with the adafruit if enough people buy/develop for them. Time will tell. Sadly, Particle may be DOA unless they have a trick up their sleeve that I don't know about.

scalz

I think adafruit core is nice, and they added freertos which is a nice touch too. So, in case, I can easily reuse some modules I wrote for esp32 projects (which is freertos based too, out of he box)

Good to know, it's not perfect, both cores, nrf5 adafruit or arduino-mbed, unfortunately miss some sdk files..

I like Adafruit core so far, but Segger IDE with full sdk support is very convenient, because spending time in arduino cores linking missing libs etc is such waste of time, vs coding fun features..

NeverDie

@scalz Yes, you raise a good point about Segger.

I'll try both the Adafruit and the Arduino versions and report back my impressions afterward.

NeverDie

I gave the Arduino Nano 33 BLE Sense a try just now. I'd say it's beginner friendly in the sense that you can simply plug it into USB and program it that way through the Arduino IDE: no getting confused or stuck burning the flash using an st-link or similar.

Blink compiles into a roughly 80KByte binary, and I presume most of that is overhead of the included mbed platform. This isn't really a problem though, because the nRF52840 has an abundance of flash--probably more than you'll ever need, even with mbed consuming part of it.

As for the sensors that are built onto the 33 BLE Sense, you need to load libraries for each one that you want to make use of, but it appears that those libraries are available.

I get the impression that Arduino has typecast the nRF52840 as primarily a bluetooth device. I see no mention of the radio's proprietary mode. That is perhaps unfortunate, because Bluetooth per se isn't easy, and proprietary mode is actually much easier.

On the other hand, maybe easier-to-use Bluetooth libraries will eventually arise. I guess time will tell.

alowhum

@NeverDie This is a bit of a side-question but to what degree could Arduino's Bluetooth support fulfill the role MySensors plays?

In theory it seems Bluetooth could be a useful smart home communications platform:

Just like MySensors, Zigbee, Z-wave, it avoids using the IP stack, and generates a separate network for smart devices. This lowers risk to user's home network.
Lower energy than WiFi. Lower energy than NRF24 too?
The killer app: it's built into smartphones, tablets and Raspberry Pi's already. No need for an extra dongle.

What I don't know is

To what extent Bluetooth has useful smart home profiles
To what extent Arduino devices could present themselves as smart home devices using those profiles.
To what extent older Bluetooth chips can work with newer device profiles (it would seem a software upgrade should be enough?)

Maybe this should be a separate post :-)

mfalkvidd

@alowhum interesting idea. Maybe add low-power features to the list. Bt-le has some very nice low-power features, but will it be possible to use them in custom sketches?

Nca78

@alowhum hard to say if the best would be to get rid of the gateway and program adapter for bluetooth devices, or to make a bluetooth gateway between bluetooth network and mysensors serial protocol.
In both cases we could have some custom profiles for the types of sensors used by MySensors.

NeverDie

@alowhum Good questions. From a distance, Bluetooth seems near ubiquitous. Closer up, the capabilities seem governed by the available "profiles" baked into a particular implementation, and that's where the apparent ubiquity seems to fall apart. There are long range modes that 5.2 Bluetooth BLE can support, but which of the profiles implement them? Those would be the set of profiles worth considering. Of those profiles, which one would be the best fit? Maybe knowing that would be a step toward answering your questions.

https://www.bluetooth.com/blog/5-videos-that-prove-thelong-range-capabilitiesof-bluetooth/

alowhum

Here is the datasheet of the actual Bluetooth module on the Arduino 33 BLE (PDF):
https://www.u-blox.com/sites/default/files/NINA-B3_DataSheet_(UBX-17052099).pdf

Here is a list of Bluetooth profiles:
https://en.wikipedia.org/wiki/List_of_Bluetooth_profiles

Mesh networking profile details (PDF):
https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?doc_id=429634

I'm trying to figure out:

Can these Arduino's even present themselves as a specific Bluetooth profile? E.g. as a bicycle cadence sensor, or a smart lamp, etc.
Can these Arduino's be programmed via Bluetooth?

the Mesh profile would be interesting:

Mesh Profile Specification[10] allows for many-to-many communication over Bluetooth radio. It supports data encryption, message authentication and is meant for building efficient smart lighting systems and IoT networks.

Application layer for Bluetooth Mesh has been defined in a separate Mesh Model Specification.[11] As of release 1.0 lighting, sensors, time, scenes and generic devices has been defined.

The Bluetooth module documentation says it has hardware support for mesh networking. Nothing else though.

The Bluetooth mesh networking spec only seems to support very basic things like lamps though. No advanced things like thermostats.

Other interesting things:

According to this blogpost, Arduino exposes the full MBED options.

Apparently you double-tap the reset button to be able to access the bootloader. Nothing about wireless upload of sketches via bluetooth though.

Here are some examples from Arduino on what you can make:
https://github.com/arduino-libraries/ArduinoBLE/tree/master/examples/Peripheral

rozpruwacz

@alowhum said in Everything nRF52840:

Can these Arduino's even present themselves as a specific Bluetooth profile? E.g. as a bicycle cadence sensor, or a smart lamp, etc.

Bluetooth profiles are nothing more than just a set of rules how to structure software ofluetooth profile means that your device provides attributes to read/write described in that specific profile. You can present your device as specific prfoile but not implement its requirements, but in that case other devices will not work properly with yours. So the answer is yes - its just the mater of the software.

alowhum

@rozpruwacz Indeed. This example sketch of a bluetooth battery monitor looks pretty cool:

https://github.com/arduino-libraries/ArduinoBLE/blob/master/examples/Peripheral/BatteryMonitor/BatteryMonitor.ino

Lots of new Arduino functions to manage services are described here:
https://www.arduino.cc/en/Reference/ArduinoBLEBLEbegin

And here's a list of possible characteristics:
https://www.bluetooth.com/specifications/gatt/characteristics/
E.g. Gust Factor, Heart Rate Max, Last Name, Latitude, etc

Looking at that list I don't see a lot of overlap with MySensors :-(

Also, bluetooth mesh does not seem to support BLE long range mode. The mesh aspect is technically outside of the official bluetooth spec.

NeverDie

@alowhum With the arrival of the Arduino nano BLE, I'm hoping that some easy-to-use Arduino BLE libraries will become available. In the meantime, Nordic's Bluetooth stack is certainly available and free to use. It didn't look especially easy the last time I looked at it, but that was quite a while ago. Maybe by now either Nordic or someone else has simplified it? For mainstream uses, it certainly should be easy to use without having to know every little detail about the Bluetooth standard. And since Arduino doesn't seem interested in the proprietary modes, I should think there would be pressure for developing such Bluetooth libraries. After all, it's very name is "nano BLE". Therefore, it's reasonable for people who buy it to expect it to be Bluetooth capable. :wink:

NeverDie

At the very least, I would expect Bluetooth to be a useful complement to mysensors. For example, outputting diagnostic println's to a simple Bluetooth terminal app on your tablet or cell phone. And if it can do even just that minimal amount, it could be leveraged to do a lot more too.

monte

There seems to be https://github.com/sandeepmistry/arduino-BLEPeripheral library. I tried it some time ago, it was working pretty straightforward. I mean it's not ideal, obviously, but it works for a start.

heinzv

anybody seen this new Nordic IoT MCU:
https://www.nordicsemi.com/Products/Low-power-short-range-wireless/nRF5340

So far only a DK board for 49$ is available. Has BLE 5.1 (incl. long range).
I guess it will take some time till it is supported by Arduiono, Platformio etc.

I'm still striggling with the nRF52840 and the low power sleep. So far I'm far away from the 1.5 to 5uA in sleep mode. Maybe someone has a good example for a sleep, internal timer wake-up.
The mysensors project I'm using has 1,5mA in sleep and 15mA during sensor read and send. That is not usable for battery mode.

monte

@heinzv try powering off all peripherals that was used before sleep.
The best source of information concerning nrf5 chips is Nordic's devzone. For example look at this thread: https://devzone.nordicsemi.com/f/nordic-q-a/45355/how-optimize-high-current-consumption-in-sleep-mode-using-nrf52840.
As far as I'm concerned nrf52 library for Arduino contains Nordic SDK, so every function mentioned in Nordic's tutorials and examples should work with Arduino IDE.

heinzv

@monte thanks for your hints. I have actually no peripherals attached during my test. The only external peripheral is a Sensirion sensor (not attched during the power save test) has an auto switch off, but no explicit and it gets down to nano amps.(at least far less than 1uA).
I did a lot of research in the Nordic DevZone but was not successfull. It looks like that the mySensors sleep functions for the nRF52 family does not work as I have expected (I'm using the MyBoardNRF5.h/cpp which includes some kind of Nordic power save features). It might have something doto with the UART switchoff which might not works or ...
I'll also try other nRF52840 moduls to ensure it is not because of one product. I'm using a bare nRF52840 from RFstar which has no LED or any other consumer on it.
https://www.aliexpress.com/item/32921970101.html?spm=a2g0o.productlist.0.0.33f77b08ivGnJC&algo_pvid=834cd241-fead-40dd-a423-762eeaad1e6b&algo_expid=834cd241-fead-40dd-a423-762eeaad1e6b-29&btsid=7de062ad-ecfb-4619-bea6-f9bc99c99996&ws_ab_test=searchweb0_0,searchweb201602_8,searchweb201603_52

Nca78

@heinzv said in Everything nRF52840:

anybody seen this new Nordic IoT MCU:
https://www.nordicsemi.com/Products/Low-power-short-range-wireless/nRF5340

Looks like NRF52832 is replaced with nrf52833 also, 128K RAM and same radio than nrf52840 allowing the same protocols (zigbee/thread), the same max input voltage (5.5V) and adding bluetooth 5.1. Interesting if it can replace nrf52832 in existing modules.

monte

@heinzv by peripherals I mean UART, SPI, I2C and other modules, that can be switched off in NRF52840. Going to sleep mode doesn't disable them, they will still drain current. And as you mentioned by yourself Mysensors sleep function can't be trusted either for doing this for you. I think the best practice will be writing your own sleep function using Nordic's macroses. This way you can be sure everything that needs to be turned off is turned off.
Try reading this thread: https://devzone.nordicsemi.com/f/nordic-q-a/1657/how-to-minimize-current-consumption-for-ble-application-on-nrf51822.

NeverDie

Andreas Spiess recently gave his review on on the two new Arduino "nano" 33 BLE offerings (which use the nRF2840):
https://www.youtube.com/watch?v=8GLXSebQVCE

He seems cautiously optimistic about the BLE 33s. From his perspective, now that the hardware is being sold, the onus is on Arduino to make the Arduino hardware libraries run on it in a transparent way, just like all the other Arduino's that we're all familiar with. Hopefully that does happen. In the meantime, and even if it doesn't, there are the mBed libraries.

The only reasons he gives for preferring the ESP32 over the Arduino BLE 33's are the ESP32's faster speed, larger memory, and the ability to do OTA firmware updates. As for where the nRF52840 scores big over the ESP32, the things he mentioned were that it consumes much less power and it can be a USB host.

I'm hoping that BLE 33 OTA firmware updates will be solved by somebody soon and made available as part of the Arduino IDE, just as it eventually was for the ESP8266. I mean Nordic already has a highly secure FOTA, so it just needs to be exposed in a way that people can easily use it through the Arduino IDE. If that never happens, then I'd wager the lack of it will kill the BLE 33. Likewise, if it does happen, it may very well propel BLE 33's success.

Interestingly, Andreas points to a $5 nRF52 Ebyte module as a cost equalizer, so he doesn't seem to see cost as a discriminator, especially not in the long term.

By the way, and unrelated to the above, there is now yet another radio standard vying for IOT adoption. This one, made by Radiocraft: https://www.digikey.com/en/articles/techzone/2019/sep/how-to-quickly-start-low-power-wireless-iot-sensing The energy performance specs sound maybe better than LoRa or SigFox, so who knows? It can do OTA firmware updates by the way. With the marketplace becoming more crowded, FOTA is now an important must-have for being taken seriously. Why do I say that? Any vendor who has a FOTA is devoting at least one entire slide to it in their marketing presentations.

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