SIM 300 V7.03 Under Voltage Warning

[anil404]

Hi all,

i have a sim300 gsm module , when i give commands its giving UNDER VOLTAGE WARNING . what is the reason to get this warning . How to resolve it. The modem is using 7805 regulator is it k ot shall i replace with LM317.

i found the reason is due to low volatge at VBAT<3.5.
How to resolve it.

 

[tpetar]

Boost voltage to needed voltage, or use adequate power source.

You probably try with Li-Ion battery, and voltage falldown under load.

To use 7805 at least 2,5V-3V difference is needed between input and output voltages.

 

[anil404]

thank you for your reply tpetar,

I am also having problem with sim900A. The modem is continuously restarting after registration.

What may be the problem ?

 

[tpetar]

SIM900A restarting due to lack of power.

 

[gautiraam]

when i run the batch file "run"...then mode sets to read(at+cmgr=1) and its starts to read the first message continuously...can any1 please help me out of this??
thanks!!!

 

[anil404]

when i run the batch file "run"...then mode sets to read(at+cmgr=1) and its starts to read the first message continuously...can any1 please help me out of this??
thanks!!!

As per i know In at+cmgr=1 , 1 indicates message number . So it reads msg 1 continuously.

 

[gautiraam]

As per i know In at+cmgr=1 , 1 indicates message number . So it reads msg 1 continuously.

yeah....it's happening like that only...but if i send messages it's not responding...is there any possibilities to reset it?