Random data points...
Powering the module from the high power USB port (the one with the
lightning bolt next to the USB symbol) is rock solid. GSM connection is
2 "bars", as displayed by Android app. Doesn't matter if WiFi is on or
off; nicely stable. I just have a ham radio HT antenna screwed into the
GSM port (well, it was handy, and I don't have a real GSM antenna).
If I power the module from my Raspberry Pi 2 (with USB high power
enabled), the module overall is stable (doesn't crash), but the modem
never makes it up - the power on message pair just repeat every few
seconds. WiFi works, however.
Greg
Mark Webb-Johnson wrote:
I too have started to see these under-voltage warnings. I’m wondering if it is something to do with the work we recently did to enable GPS. It doesn’t seem to be a problem with powered HUBs or high power boards, so is most likely an actual low voltage condition.
Regards, Mark.
On 16 Dec 2017, at 5:59 PM, Tom Parker <tom@carrott.org> wrote:
I've found the SIMCOM modem is very unstable when connected to my laptop via an unpowered USB hub. I see under-voltage warnings so I wonder if there isn't enough power? It seems stable when connected directly to my laptop. When it the modem reboots, the esp32 crashes too. I'm not sure if this is because it also ran out of power or because it is sad the network went away: