Custom boards based on LoRa-E5 and RAK3172

Hi there,

Long time here without designed a public LoRaWAN node board, so with new STM32WL all in one modules based on STM32WL55 available, I went further for investigation in custom node design for testing. Since one of my first Low Power LoRaWAN node with Arduino (OMG 4 years ago) and 1uA consumption has been so popular may be this one will also

So I made 2 boards based on 2 popular modules, one for LoRa-E5 module from Seedstudio and one for RAK3172 module from RAK Wireless. Easy to provide, easy to hand solder and so cheap, love them.

To my surprise, they works out of the box, they have plenty of flash and RAM so it’s really a huge progress in 4 years and now we can put awesome code on it such as mbed-os based firmware, so nice. I’m also pretty sure it could be easy to run Generic Node firmware on these one with some changes, so if someone does, just let me know here. I also know @disk91 was thinking adding STM32WL to his excellent sdk

I’m sharing here, I’m pretty sure they would interest the community:

LoRa-E5
image

RAK3172
image

See readme on their dedicated repo github

Of course I’m not using these board with original AT modem but with custom firmware. I switched now to mbed-os and boards have been added to stm32customtargets for those who want to play with mbed-os.

Here my experience on these 2 modules:

  • Smaller (LoRa-E5)
  • Thicker (LoRa-E5)
  • Easier Soldering (LoRa-E5)
  • Available # of GPIO (RAK3172)
  • on board Ipex (u-FL) connector (RAK3172)
  • No STM32WL RF_LP path, both works only with RF_HP (mainly due to BOM and size constraints)
  • TXCO (LoRa-E5) RAK3172 must be configured/drived with No TXCO
  • Price (RAK3172) $5.99 against $9.90 for LoRa-E5 ($8.90 by 10+)
  • With original FW they can both do interesting LoRa tests (but not tested this one)

Have fun

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Hi @Charles,

Nice boards!

Can you share some information about their power consumption?

@bluejedi this is the next step I need to do, module are announced from 1 to 2 uA sleep mode but looks like nasty bug not fixed on mbed lorawan example. So for now I’m still looking for the best (and easier) pro framework to use with.

I also got some sample with STM32WL framework but to be honest it’s not easy to work with due to the number of files and folders used. Also Generic Node SE source code looks great so I’m thinking using it if we can set these CPU targets into

What about the future stm32duino support?

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I wonder if stm32duino will add LoRa support for the STM32WL. In the main README under Nucleo boars it says no. But maybe it’s Nucleo specific and available for the generic micro?

image

If they do support the WL55 for LoRa, hopefully they will bring the I-NUCLEO-LRWAN1 up to date (from 2018) and perhaps provide support for the B-L072Z-LRWAN1. :crossed_fingers:

may be it will also be supported by generic node code, see this one I opened few days ago.

Also I made these boards enabled with stm32customtargets from mbed

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