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I have about 20 nRF52840 boards deployed around my house for various automations. Personally I've found that for casual experimenting and software development,

by kpc 3y ago

I have about 20 nRF52840 boards deployed around my house for various automations. Personally I've found that for casual experimenting and software development, the official nRF52840 DK board is your best bet. Here in the US it only costs around $50, and all of the samples in the nRF Connect SDK support it natively. It's also pre-wired for power measurement. My first board was the nRF52840 MDK from makerdiary. I ordered it from Amazon because it was cheap and it had one-day delivery. Most of the NCS samples do not support the makerdiary boards as-is. You can usually add a dts .overlay file to the sample to get it working, but it will take a bit of extra effort. Having to tweak device trees right off the bat adds another step to the learning curve and makes it harder to try out random sample apps. Over time I migrated to using the DK for development (the integrated debugger + serial interfaces are super handy) and then using the USD $10 nRF52840 Dongle boards for deployment. I program the dongle boards using a knockoff J-Link probe from Aliexpress and run them off battery power. I eventually stopped using the makerdiary MDK since it didn't really fill a niche for me. But YMMV. One nice thing about the board in this article is that it has an external SPI flash, which could be useful if the nRF52840's 1MB onchip flash isn't large enough for your application. I use A/B partitions to support OTA updates and it's pretty easy to run over 512kB per image if your use case is moderately complex.

makerdiary 3y ago
nRF Connect SDK is supported now: https://wiki.makerdiary.com/nrf52840-connectkit/guides/ncs/ https://wiki.makerdiary.com/nrf52840-connectkit/guides/ncs/
- kpc 3y ago
  Hi, nice to see the vendor participating in the HN discussion (and hopefully gathering feedback from users) :-) One of the main factors driving me back to the DK board was the fact that many NCS samples take advantage of the 4 switches + 4 LEDs on the DK board. Even the light_switch sample uses all 4 buttons to trigger different functionality. The smaller boards don't have room for these switches and LEDs, so you'd have to tweak the program to work around the hardware differences. And that's a big investment if you just wanted to play around with the stock sample code for a few minutes. A more general critique of the NCS samples is that many of them require a great deal of "polishing" before you can use them in a real project. It would actually be helpful if NCS shipped ready-made overlays that allowed them to run on smaller boards like the MDK and Dongle, in a configuration that's closer to what a shippable product would look like. As it stands, a company that wants to ship a Zigbee bulb or switch has to do a lot of work to convert the samples into something usable. Maybe this is worth filing some PRs on the sdk-nrf github.
ChuckNorris89 3y ago
>I have about 20 nRF52840 boards deployed around my house for various automations. Is there an advantage of using the NRF boards over ESP ones for home automation?
- grawp 3y ago
  Non-obscure architecture, one of the most used Core in the world (Cortex M4), true Floating point coprocessor, non-chinese firmware for BLE, if are not afraid of doing full certification it can also be non-proprietary Wonderfull documentation. Ready made modules can be obtained at the same price as ESP32. You support EU chipmaker.
  - grawp 3y ago
    Also absolutely wonderful documentation directly from Nordic Semi (for the peripheries) and from ARM (for the basic core).
- vardump 3y ago
  Power consumption might be one major advantage.
  - tomn 3y ago
    this is the big one for battery-powered applications NRF52840 is specified to use 1.5uA when deep sleeping with RTC wake-up, while esp32-c3 is 5uA, which sounds ok, but is not the whole story. If you try to build something low-power with ESP32 you'll find that it takes a lot of time and energy to go from deep sleep to being able to transmit, while the NRF SDK is designed with that in mind. The NRF current consumption also includes the built-in voltage regulators -- this works from 1.7v to 5.5v, with a regulated output for peripherals, so all it needs is a battery and some passives. On the other hand the ESP32 is much more awkward -- it needs 3-3.6v, so you're going to need an external regulator, and a LDO with the required 500mA output current is going to have a significant quiescent current, and even then the voltages are awkward for lithium batteries once you consider the drop-out voltage. The tl;dr is that it's easy to get multiple years out of a coin cell with an NRF-based sensor, and that's just not happening with any ESP32.
zh3 3y ago
The Adafruit nrf52940 feather is a great companion to the DK, since it has the 10 pin header on it for SWD programming. When the cable is connected, the DK switches to programming the offboard (Adafruit) nrf52840 so it's pretty much transparent. So easy to develop on the DK and deploy on the Adafruit.
moffkalast 3y ago
> it only costs around $50 "only" One could buy at least like a dozen ESP32 boards for that price and probably get better support as well.

by kpc 3y ago

makerdiary 3y ago

nRF Connect SDK is supported now: https://wiki.makerdiary.com/nrf52840-connectkit/guides/ncs/ https://wiki.makerdiary.com/nrf52840-connectkit/guides/ncs/

kpc 3y ago
Hi, nice to see the vendor participating in the HN discussion (and hopefully gathering feedback from users) :-) One of the main factors driving me back to the DK board was the fact that many NCS samples take advantage of the 4 switches + 4 LEDs on the DK board. Even the light_switch sample uses all 4 buttons to trigger different functionality. The smaller boards don't have room for these switches and LEDs, so you'd have to tweak the program to work around the hardware differences. And that's a big investment if you just wanted to play around with the stock sample code for a few minutes. A more general critique of the NCS samples is that many of them require a great deal of "polishing" before you can use them in a real project. It would actually be helpful if NCS shipped ready-made overlays that allowed them to run on smaller boards like the MDK and Dongle, in a configuration that's closer to what a shippable product would look like. As it stands, a company that wants to ship a Zigbee bulb or switch has to do a lot of work to convert the samples into something usable. Maybe this is worth filing some PRs on the sdk-nrf github.

ChuckNorris89 3y ago

>I have about 20 nRF52840 boards deployed around my house for various automations. Is there an advantage of using the NRF boards over ESP ones for home automation?

grawp 3y ago
Non-obscure architecture, one of the most used Core in the world (Cortex M4), true Floating point coprocessor, non-chinese firmware for BLE, if are not afraid of doing full certification it can also be non-proprietary Wonderfull documentation. Ready made modules can be obtained at the same price as ESP32. You support EU chipmaker.
- grawp 3y ago
  Also absolutely wonderful documentation directly from Nordic Semi (for the peripheries) and from ARM (for the basic core).
vardump 3y ago
Power consumption might be one major advantage.
- tomn 3y ago
  this is the big one for battery-powered applications NRF52840 is specified to use 1.5uA when deep sleeping with RTC wake-up, while esp32-c3 is 5uA, which sounds ok, but is not the whole story. If you try to build something low-power with ESP32 you'll find that it takes a lot of time and energy to go from deep sleep to being able to transmit, while the NRF SDK is designed with that in mind. The NRF current consumption also includes the built-in voltage regulators -- this works from 1.7v to 5.5v, with a regulated output for peripherals, so all it needs is a battery and some passives. On the other hand the ESP32 is much more awkward -- it needs 3-3.6v, so you're going to need an external regulator, and a LDO with the required 500mA output current is going to have a significant quiescent current, and even then the voltages are awkward for lithium batteries once you consider the drop-out voltage. The tl;dr is that it's easy to get multiple years out of a coin cell with an NRF-based sensor, and that's just not happening with any ESP32.

zh3 3y ago

The Adafruit nrf52940 feather is a great companion to the DK, since it has the 10 pin header on it for SWD programming. When the cable is connected, the DK switches to programming the offboard (Adafruit) nrf52840 so it's pretty much transparent. So easy to develop on the DK and deploy on the Adafruit.

moffkalast 3y ago

> it only costs around $50 "only" One could buy at least like a dozen ESP32 boards for that price and probably get better support as well.