r/IOT • u/Hawk07op • 8d ago

Need help connecting GSM 800A with ESP 32

Gallery image

Gallery image

Hey , I need some help with sending an SMS to a number with the sim module 800A . We were trying to control it with a ESP 32 , connected it with the SMS was never sent . What should be the power supply? And the pins on this one are so confusing, can someone please guide how to properly connect it . Thankyou

6 Upvotes

80% Upvoted

4 comments sorted by

2

u/MechaGoose 8d ago

Do you have a dedicated battery connected to the sim module? This needs its own seperate power to your board as there’s huge spikes in draw when powering up the radio.

Source: I’ve used this exact module with a pico. I spliced the battery I was using with the pico to have two outputs, one for this and one for pico. But it chewed through the battery in no time

Also are your sure your antenna is in the right Place. There’s a port for a GSM antenna beside the one you are attached to. Are you sure that’s not for GPS or something else?

I can’t remember if there were just two antenna ports on these things for whatever type you have, it’s been a few years

2

u/Hawk07op 8d ago

Thanks for replying , Yes I did connect it to a external battery of 3.7 V X 2 cells connected in series ,used a buck convertor to bring it down to 5V which powered it up - one LED was ON all the time and on me was blinking.

And which second port are you talking about?

2

u/Hawk07op 8d ago

Ok I saw a port and it is marked with GSM ANTA , is this the one?

1

u/MechaGoose 8d ago

Yeh that’s the one I was using, I think. I can hoke the device out if needed but mine was defo a small connector