Saturday, 9-January-2021

SIM800L GSM module + Arduino, my first test

EN

In that part, will try to explain my effort to do some primary test with GSM module SIM800L and arduino Nano.
Yes, in fact there are many ready library, ready tutorials or examples over the internet that show similar projects done. I did not discover the fire for everyone.. just small light for myself.

What was my initial intent?
To make some device that I cans send SMS to, with some commands and when it recognize it send some answer(if requested).
Some of the ready projects you can find request weather station data, or sensor`s data. In my test, it follow just base concept that can be made more complex if need.

How is all connected?
GSM - Arduino
5V Vin > both to +5V
GND GND > common GND
TX D10
RX D11
RST D2

Here, before to continue , need to mention: the 5V supply to the GSM module need to be at least 1.5A. Yes, it draw quite small amount of current during work. But at the beginning, when network signal is searched consumption can reach even 1.5-1.8A.
In my first attempt the power led of the GSM module start blinking I it looped in some self reset mode because of that.
Also, I have to “fix” that small module:

gsm_module.jpg

You see that extra capacitor? Yep, that was also second reason causing module to reset itself.

Software: Arduino sketch can be downloaded here
The serial debug will look like that:

gsm_serial_output.jpg

How all work? You send command in that type: <4&0@Y>
That is digital pin[4], next is what we do for that pin, turned off[0] or on[1]. after “@Y/N” will request or not sms back to confirm what is done.

In action, you can see it here:

Hope that small project will be also in some help to you reading it.