AM02 Module Plus suit my project?

#1

Hi There, I just discovered this board and I think it may meet the requeriments for my project. One of the things I find most valuable is that everything is already in the same package with full Arduino support and (supposedly) all well soldered and interconnected together with the spot components, clock, RF/EMI shield etc…

Can any one confirm this module meets my requeriments?

  • :white_check_mark: Code always running / listening so don’t care about sleep features
  • :white_check_mark: Bunch of free GPIOS
  • SPI (to connect to the LoRa module) and I2C for a external sensor working at same time
  • Interrupt for 2 inputs, just to know from the micro that something happen as soon as possible rather that pooling it.
  • Lora / FSK messages
  • Good RTC/Clock accuracy, I’m aiming to get <5 mS / minute (counting time while CPU active)
  • 15mA or better running both CPU working and LoRa on listening mode.

I take a general overview on documentation and github and looks good, just concerned about the micros (1,2) issue that seems to be still unfixed, not sure if this board it’s too old / abandoned and will no get more support and should move on into another model…

I am very grateful for any help, also any kind of confirmation about real power draw and clock drift will be very useful :kissing_closed_eyes:
Regards!

#2

It’s not totally clear if you want to use the LoRa radio - it’s more by implication - and if you want to use LoRaWAN.

The original Heltec code base works but comes with a bit of a learning curve & some poking to get going.

The RadioLib LoRaWAN maintainers tried their CubeCell and are still in therapy so please don’t plan on using RL with this board as no help will be forthcoming - far too much drift for timings for the RL implementation,

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#3

Which for 50% comes down to the micros practically not being usable and 50% due to the massive clock drift, so …

… you’re plain out of luck on this one. ASR650x drifts by about 1.6%: 16ms every second. So that is far over your tolerance.

Given your requirements, I’d suggest maybe one of the larger ATmega chips.

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#4

You right, I have edited my original message, I’m planing to use LoRa (or perhaps FSK or any other sx1262 modulations) as I’m not going to need more than 150m range and aim to spent the less time in air possible

:rofl::rofl: Understood

#5

I see, I thought that 16ms drift was only with micros() but not millis() that seems to use an accurate clock, now I have the concern.

Is there any other one solution/package (cpu + sx1262 < 15mA) with Arduino support out there? I always can just pick an sx1262 module and separate cpu but I’m trying to make the circuit as simple and reliable as possible. Also I want to o avoid board and traces mistakes with external components (crystal, caps etc…) as I’m not the best PCB designer :relaxed:

#6

You may try an STM32WL through STM32duino platform. The two of us that responded here may try it out, too, in due time.

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#7

The https://heltec.org/project/ht-ct62/ is a combined ESP32-C3 and SX1262. This might be worth a look too

#8

Thanks but an ESP32-C3 can’t archive less than 15mA (including the sx1262) not even power off :rofl:

#9

You’re mostly incorrect on the last statement - it does 10uA during deep sleep. And with low clockspeed, ~40mA while active + Rx mode

#10

Yeah, was a joke meaning the ESP it’s power hungry even with no power (no wires, not connected)

As I said multiples times, I don’t care deep / light sleeps as I’m going to use always the CPU, so ~45-50mA with LoRa RX it’s far from what I was looking for

#11

Very good alternative, thanks man!
I will take a look as it seem to have an special API for LoRa stuff and that can be soo good or soo bad :thinking:

#12

Thanks for that, that now means my reply appears odd & out of context, not good forum etiquette at all.

Google brings up more than a few - the RocketScream Mini Ultra LoRa comes to mind.