If we takeout the RAK4270, you should at least see set to OTAA because of the line print("set to OTAA").
Is the Rpi PICO working properly? Can you check via an oscilloscope or logic analyzer if there’s a UART output going to RAK4270? Also, can you try to test first the RAK4270 via USB-Serial converter?
I do receive “set to OTAA” with or without the RAK4270 connected. I tried with a second new Pico and still nothing. No response using a USB to serial converter either. Thanks Carl
Alright. We focus first on the RAK4270. Please check the connection.
USBtoUART - RAK4270
3.3V - 3.3V
GND - GND
TX - RX1/PA10
RX - TX1/PA9
If you are using jumper wires to connect them, ensure the continuity using a multimeter. Sometimes jumpers wires are not reliable.
Set baudrate to 115200. Send to RAK4270 at+version. This should at lease show the version of the device.
Btw, you have no success yet on your RAK4270?
It wouldn’t go amiss to share the Pico code - I can see the Matrix …
Success! Nothing like swapping out bad jumpers for more bad jumpers… I opened a new pack of jumper wires and now everything is working perfectly. I would never have guessed it was a bad wire(s). Thanks for your help!
That’s great @RGS !
Actually, I expressed it wrong when I said sometimes jumper wires are not reliable. It should be most of the time they are not reliable.
I usually solder wire wrapping wires to interconnect modules securely.
Not if you buy ones that cost twice as much as the ‘going rate’ that are advertised as “definitely working” - but very hard to tell who to trust.
I have a box of connectors, outer shells & a crimp tool. Plus students to test stuff (like batteries).
Hi Guys, i’ve a problem with the code, when i run it on raspberry Pico it return None on data = uart.readline()
And logically when i try to decode the data variable the error is: AttributeError: ‘NoneType’ object has no attribute ‘decode’
Some suggestions?
Cheers!
Welcome to RAK forum @umbertowski ,
Can you try first a UART loopback test on your RPI Pico? Or try to connect it to a PC via USB-UART converter and replicate the module? Also, is the RAK42xx working well if you use a USB-UART converter?
when i connect the RPI Pico to a PC i don’t see any problem
The problem it isn’t the rak module because i’ve tried to change it and the error still remain, i don’t think the RPI Pico is broke or other because when i connect it to a PC the machine and Thonny recognize the board, maybe the cables i used for connect the module and the RPI are damaged?? like @RGS problem?
I really can’t say @umbertowski .
But I highly encourage you to test the modules first, then the Rpi PICO. Doing individual test will help you pin point the root cause of the problem 
I have solved the problem with a try before every decoded_data = data.decode('utf-8')
Which core is a better alternative to the RAK11300 (RP2040) for a LoRaWAN application in terms of deep sleep?
If you are asking what LoRa module, I suggest you check RAK3172.
The question was which Core Module w/ integrated SX1262.
Currently, for WisBlock Core module, it is the RAK4631.
We also have a core based on RAK3172 but the custom firmware support (RUI V3) is not yet released (probably Q2/Q3) but the board is already available. At the moment we are not selling the RAK3172 based Core as independent product.
Btw, welcome to RAK forum 
Ok, I have seen it. Based on STM32 it looks very interesting. Now I will start with RAK4631 without BLE to reduce power consumption. Also, I will replace M5Stack ENV.II unit with RAK1902 as there sensor can go into sleep mode. I am curious about the runtime of the LoRaWAN node with a transmission cycle of 30 min. I hope that the solar support is helpful.