warning: invalid conversion about arduino-sim808

[blemasle]

Hi. You can ignore that warning, but I'll try to have a look and get it fixed :)
To dig into why you're not getting a fix, you can turn on console debugging by forcing _SIM808_DEBUG to 1. See here

This will print every command sent and their responses to be printed on Serial.
Let me know if I can help you further.

[ser]

Debugging does not show things verbose enough, from your library i am getting:

18:41:53.468 -> -->AT+CGNSPWR?
18:42:03.750 -> 
18:42:03.750 -> -->AT+CGNSINF
18:42:04.811 -> N: No fix yet...
18:42:07.828 -> 
18:42:07.828 -> -->AT+CGNSINF
18:42:08.889 -> N: No fix yet...

and with a simple serial script I get:

18:39:03.065 -> AT+CGNSINF
18:39:05.087 -> +CGNSINF: 1,1,20190704113904.000,10.786985,106.711155,161.100,5.93,253.6,1,,5.0,5.1,0.9,,5,4,,,36,,

So in summary I have no idea what is precisely going on, what values are sent from GPS and why library thinks that there is no fix :(

[blemasle]

You should get a full log with for instance the GPS string returned by the SIM808. Here you just don't get any response from the board.

Can you share a full log from the beginning of your sketch ? Also, can you share your sketch so I can understand what's going on and why it's not working when it definitely should ? :)

[ser]

Yeah, I think I started to understand what is the reason. My board:

https://www.elecrow.com/wiki/index.php?title=Elecrow_SIMduino_UNO%2BSIM808_GPRS/GSM_Board

looks like does not have SIM808 STATUS - or I am unable to find it. It makes the library got completely stuck on init.

[blemasle]

Please have a look at the Readme. Support for boards without the STATUS pin has been added a while ago.

Can you share your initialization code ?

I might try to add support for serial pins only boards. It has come up several times, but it drastically changes the library abilities regarding power on/off.

[ser]

All good now :) Thanks for a hint, I had to remove STATUS from initialisation:

SIM808 sim808 = SIM808(SIM_RST, SIM_PWR);

and now it is brilliant :)

But I am really disappointed about location precision, I will upgrade to NEO-N8M and just use GPRS functions from the SIM808.

[blemasle]

Glad you've got it working, and hope this library will be useful to you.

I haven't had the time to work on it but I'll try to implement "pin less" library constructor.

About that GPS location, have you waited long enough ? On a cold boot, it might need up to 30 seconds to get the first GPS satellites. After that, you shouldn't consider a fix with less than 4 to 6 satellites as an accurate fix. That what minSatelliteeForAccurateFix is for :)
You can also look at hdop and vdop values and see if they improve over time. The lower the better.

[ser]

yeah, in theory i had minimum 4 satellites fix, and with 20 seconds sampling on my cycle it shows track like this:

maybe it is because of asian location... Ublox Neo M8N has also chinese system, so probably it will be better! and has faster cold fix either, as my 808 board does not have battery nor flash :(