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Topic: GSM Module SIM800L no signal? (Read 8217 times) previous topic - next topic

Marko297

Hello guys,
I bought a SIM800L module but I get a problem ... the LED flashes 7 times fast (1 flash per second) and 1 flashes after 3 seconds.
The module is powered by 5V from a computer power supply, the voltage has been lowered to 4.2V via a 1N4001 diode and placed two 200uF capacitors in parallel to the output.
The card does not have a PIN, it is inserted correctly,I'm using the "original" antenna (the spiral one) and the SIM on the phone works.
It only worked one time. My intent is to send SMS but I can not because it does not connect to the network.

This is what serial comunication return to me:

AT
OK
+CPIN: READY
Call Ready
SMS Ready

AT+CSQ
+CSQ: 0,0
OK
Call Ready
SMS Ready

AT+CREG?
+CREG: 0,2
OK
Call Ready
SMS Ready

AT+COPS=?
+COPS: (1,"vodafone","voda IT","22210"),(3,"TELECOM ITALIA MOBILE","TIM","22201"),(3,"Wind Telecom SpA","I WIND","22288"),,(0-4),(0-2)
OK

AT+COPS?
+COPS: 1
OK

AT+CBAND?
+CBAND: EGSM_MODE,ALL_BAND
OK









dannable

Beginners guide to using the Seeedstudio SIM900 GPRS/GSM Shield

freaklabs

According to the SIM800L AT Command Manual, your response for
AT+CREG?
+CREG: 0,2

is decoded as:
n = 0: Disable network registration unsolicited result code
stat = 2: Not registered, but MT is currently searching a new
operator to register to

I suspect you have a problem with your SIM card. You may want to try your settings though. Perhaps:
at+creg=1

Also, you may need to attach to the GPRS service using:
AT+CGATT
and define the PDP context:
AT+CGDCONT

Good luck :)
FreakLabs
Open Source Wireless Sensor Networks
https://freaklabs.org
Twitter: @freaklabs

Marko297

#3
Sep 10, 2017, 06:24 pm Last Edit: Sep 10, 2017, 06:31 pm by Marko297
I can't use this command...

AT+CGATT?
+CGATT: 0
OK

AT+CGATT=1
+CME ERROR: 100

I'm from Italy and I'm using a vodafone SIM... on my cellphone work perfectly, and two days ago the module worked normally...if I remove the SIM Card and type AT+CSQ the result is 20,0

freaklabs

It's difficult to say. If the module was working fine a few days ago with the same SIM card, I would look into trying out a different SIM card. Can you purchase a cheap prepaid SIM in Italy?
FreakLabs
Open Source Wireless Sensor Networks
https://freaklabs.org
Twitter: @freaklabs

Marko297

I will try with other sim ... could it be an antenna problem?

freaklabs

I doubt it. If you're getting a nonzero RSSI, you probably are okay. Also, if it was working before in the same place, then its likely okay. I run into SIM card problems more than antenna issues.
FreakLabs
Open Source Wireless Sensor Networks
https://freaklabs.org
Twitter: @freaklabs

Marko297

I tried two TIM Sim Cards and worked ... 1 SIM Card was a Brazilian SIM I could not send SMS but I could read SMS while with the Italian SIM I had no problems.
So the next one reading this thread know that Vodafone SIM Card in Italy with this module does not work.

freaklabs

Thanks for posting the conclusion. I'm sure it will be helpful to many :)
FreakLabs
Open Source Wireless Sensor Networks
https://freaklabs.org
Twitter: @freaklabs

sonukushwah221

Hello

I am using sim800L with Arduino pro mini and switch VCC of SIM800L via MOSFET is working perfectly,
But when the battery goes 3.5 volts so module is not responding, it does not give the message "CALL READY" "SMS READY.

as per datasheet SIM800L operating voltage is 3.4 to 4.4 volt.

Please drop your suggestions here why is not working when the battery goes under 3.5 volt.

LLANGE

Looking at AT+CBC I had theorically adequate power... Couldn't join my operator network.

After itching and scratching (AT+COPS?, AT+CREG?, AT+CGREG?, AT+CMEE?, …). I finaly came to sense thinking that the nano board powered by USB wasn't able to sustain current whilst joigning the network...

Took another power source to provide 5V to the board as it has the built-in voltage regulators.

Now it works.
-- D6 NET led blinks every 3 seconds (instead of 1);
-- D2 RING led stay put (that's the one that made me realise the SIM800L board was restarting);

I'll try to look what kind of capacitor (instead of a battery) I should add in order to have only one power source whilst playing on the dev board. Although it's kind of useless for the final application as I will need to provide 5V to both the Nano and the SIM800L.

About SMS Sending maybe dig around:
AT+CSCA=? Googling SMSC + provider name to find the right number or with the SIM card in a working mobile dialing *#5005*7672#
EG: AT+CSCA="+393492000500",145 for Vodafone Italy

sarathkumar341

#11
Oct 31, 2018, 03:10 pm Last Edit: Oct 31, 2018, 03:14 pm by sarathkumar341
The SIM800L needs a 2Amp current while searching for the signal. It can run at 3.6v to 4.5v.

If the LED is continuously blinking it is searching for the network. If you give proper power it will get connected. I used LM2596 with a 9v 1 amp power supply to achieve it.

Check this detailed tutorial along with LM2596 Connections SIM800L with Arduino (AT Commands and Library)

nksl

I tested 2 sim800l and 2 sim900. Only this worked :



But it needs an power adapter 5V - 2.4A :

for examble


pin connect (sim800l) : 5VIN and GRD

rauson

I really need help as i  cannot start my project. The module is not working but i an get output in serial monitor, so i think der must be a way to fix it it shows "ready" but i cannot sent sms or call whatsoever. the led also blinks 7 times.
THE SERIAL MONITOR SHOWS THIS...:

Initializing...

RDY

+CFUN: 1
AT

OK
AT+CSQ

+CSQ: 0,0

OK

+CPIN: READY
AT+CCID

8991301804782159456f

OK
AT+CREG?

+CREG: 0,2

OK

Call Ready

SMS Ready

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