Hello M5Stack team

I've just realized that the COM.LTE Module (SIM7600G) only seems to be CAT1 and not CAT4 as advertised in your store. See SIMCOM description.
Only the SIM7600G -H version seems to be CAT4. See here.

I have to say, if my conclusion is correct and true, that I am quite a bit disappointed.

Care to comment?

Thanks
Felix

P.S. I understand that when used with ESP32 the speed difference probably doesn't really matter, but the SIM7600G can be used through USB with a computer as well and then the speed difference matters.

Hello @ksprayberry

the first thing you'll need to know is that the tutorial is using the 868 MHz LoRa module whereas you are using the 915 MHz LoRa Module. Unfortunately they don't use the same AT command set, so you'll need to adapt the tutorial for your module.

For instance the 915 MHz module doesn't seem to have the AT+LORAWAN=? command and that is the reason you'll get the error.

Please check out the related links section here.

BTW: the fact that you are seeing an error for the AT command given tells you that the RX/TX pins are correct.

BTW: the ASR6501:~# line simply means, the modem went back to sleep.

Thanks
Felix

Hello @jcl

this issue happens with Arduino framework 1.0.5 and when WiFi is enabled before going to sleep. See here for possible work-a-round.

Thanks
Felix

Hello @vkichline

interesting question. Looking at the schematics of M5Atom and M5Stamp it looks like they are mostly the same.
Same:

• ESP32 PICO
• RGB LED - GPIO27
• Button - GPIO39

Different:

• Groove - GPIO32/26 (M5Atom) vs. GPIO33/32 (M5Stamp)

So, yes, I'd say using the M5Atom Arduino library should get you started.

Thanks
Felix

Hello @JBecker32

ah, ok. Thank you for the clarification.

It never occurred to me to 'reuse' the M5Core2 base plate to complete the stack. It probably won't fit under any of the modules as they are all quite different regarding where components have been placed. Plus most (all?) modules are lacking a connector for the battery anyways. So yes, the question remains as to why it has been designed like that. I guess only M5Stack engineers will now.

Yes, the M5Go Battery Bottom 2 could be a solution. Please be aware though that since it contains additional hardware, it consumes additional energy. (The 10 LEDs alone eat about 1 mA each, even when they are off.)

Maybe it's time to start the 3D printer and design you own?

Thanks
Felix

Hello @JBecker32

Just to clarify: before you try to stack any module to M5Core2 you'll need to remove the small board labelled 'Core2' and the gray bottom of M5Core2. (Careful the battery is attached to the bottom.)

How can I find out which modules fit to Core2?

As @m5stack mentioned above: 'If there is any doubt, you can communicate with the customer service staff before purchasing.'

I don't own the COMMU module so I cannot test myself, but from the pictures the top side doesn't look that much different than any other module.

Do you have a module that fits under M5Core2? If yes, what is the difference? Just curious.

Just as an idea: maybe stack another module under M5Core2 first? E.g. an empty prototype module and then the COMMU module. Not ideal, I agree.

Thanks
Felix

Hello @bob_isat

all COM.X modules have an internal DC-DC converter which takes the voltage applied at the external power jack (from 5 V to 12 V) and converts it to 5.4 V (or less).

The M5Stack device (if powered from the COM.X module) always gets those 5.4 V (or less) from the output of that internal DC-DC converter (independent of whether switch S1 is set to 5 V or 12 V). So no, the 12 V are not being sent to the M5Stack device.

The switch (S1) only selects the voltage going to the LoRa board, which can either be the voltage applied at the external power jack (if S1 is set to 12 V) or the 5.4 V output from the internal DC-DC converter (if S1 is set to 5 V).

On the LoRa board itself is yet another DC-DC converter which creates 3.3 V for the LoRa chip. It's hard to find the proper datasheet for this DC-DC converter, but I think its input range is up to 18 V. So feeding it with 12 V should be fine.

I know, it's quite confusing and it took me more than one attempt to figure it out (and I could still be wrong).

I personally set the switch (S1) to 5 V and use an external power supply set to about 6 V. This allows the internal DC-DC converter to actually produce 5.4 V which then is used for both the LoRa board and the M5Stack device.

If you only use an external power supply with 5 V then the internal DC-DC converter will only produce about 4.7 V (which might be marginal in some cases).

Thanks
Felix

Hello @jesus-valencia

which M5Stack device (Fire, Base, Core2, Stick, Atom, ...) are you using? I am asking because I've tried with M5StickC Plus, M5Stack Base and M5Atom Lite and 2 m of cable between M5Stack device and ENV sensor and it worked just fine. (Note: I used UIFlow for this test.) Care to share your code?

• have you measured the voltage on the ENV sensor? (Maybe the voltage is ok?)
• since you have multiple ENV sensors, do all of them fail? (Maybe one is faulty?)
• have you tried a different power source? (Maybe the USB power supply is weak?)
• have you tried a different USB cable? (Maybe the USB cable is bad or too long?)

Thanks
Felix

Hello @bob_isat

cool. Glad you got it working. And thanks for reporting back.

Thanks
Felix