SIM800L and rp2040-zero echoes commands back
January 28, 2024, 02:40
I have a sim800l connected via uart to the pi and wrote a sample micropython code to test it, but the weird thing is that it just replies with the same command instead of executing it, in the documentation of it ive read something about echo mode, could that be an issue?
https://cdn-shop.adafruit.com/datasheets/sim800_series_at_command_manual_v1.01.pdf
even if i just send pizza' to it it replies with b'pizza', same thing with the AT commands (see code below), any ideas what im doing wrong?
py
from machine import UART, Pin
import time
uart = UART(1, baudrate=9600, tx=Pin(4), rx=Pin(5))
uart.write('pizza')
time.sleep(0.1)
response = uart.read()
print(response)
Check ATE command, https://www.elecrow.com/wiki/images/2/20/SIM800_Series_AT_Command_Manual_V1.09.pdf page 38
And if you send only AT you should get a reply OK
if i only send AT i get b'AT' back instead of OK 🤔
No, you should get "OK"
i know, this is so confusing
Connect a serial adapter directly to the SIM800 to check it
I have worked with the SIM800L but a couple of years ago most 2G nets was decommisioned in Sweden so I don't have any anymore
here in Germany GSM and GPRS will stay operational for a year or two so it should be fine, but i have already 4g modules on the way, they are like 4 times as expensive
I know
dont have one, where can i get that
USB Serial adapter, they are everywhere, amazon, ebay and ...
alr
That is two types that would suit your needs
okay, ordered one 👍
Nice
what else could be the issue? is the code wrong?
Me python serial.... I uses a lib when I have done serial to network devices (Cisco)
So yes it could be
What about using this as a starter https://pypi.org/project/sim800l-gsm-module/
I think I know what the issue is with the code, you don't send '\r\n', so it should look something like this uart.write('pizza'+'\r\n')
tried uart.write('AT'+'\r\n') and the reply is
b'AT\r\n'
will try another module probably its faulty
alr, changed module, module is ok
tried another tutorial, used this code:
py
import machine
gsm = machine.UART(1, 115200)
gsm.write('AT\r')
print(gsm.read())
https://www.youtube.com/watch?v=uKGD9oKQJSs
but still, i followed it 1:1 and still same result
I wished I had my SIM800L modules ...
i finally managed to do it! and the problem was so simple😁:
gsm = machine.UART(1, 115200)
the baud rate was set to 9600, perhaps it missed the first message because it listened to a different one before it switched, timeout would probably also work
Thats strange, the SIM800 module is autosensing on baud by default, but perhaps yous has been loocked to 115200