user25743: I have this SIM900 board and working just fine.
But i can't find a way to soft power on this board from arduino.
I read for JP pads. They need soldering first, but from my board this JP pads missing.
Know someone other way to soft power on this from arduino?


user25743: OK for anyone who has the same problem. I solved this by soldering a cable on the underside of the board on this pin (see image) on power button. Then I connect the cable to pin 9 on Arduino and run this on sketch:    
  pinMode(9, OUTPUT); 
  digitalWrite(9,LOW);
  delay(1000);
  digitalWrite(9,HIGH);
  delay(2000);
  pinMode(9, INPUT);

I don't know how it works, but it solves my problem.


user31192: Near C6 and J15 you have 2 points.  You need to solder it.
Before soldering yon can hold wire on one of it (down pin , during code execution).


25743: <p>I have this SIM900 board and working just fine.
But i can't find a way to soft power on this board from arduino.
I read for JP pads. They need soldering first, but from my board this JP pads missing.
Know someone other way to soft power on this from arduino?
<a href="https://i.stack.imgur.com/OCSYG.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OCSYG.jpg" alt="enter image description here"></a></p>
 25743: <p>OK for anyone who has the same problem. I solved this by soldering a cable on the underside of the board on this pin (see image) on power button. Then I connect the cable to pin 9 on Arduino and run this on sketch:    </p>

<pre><code>  pinMode(9, OUTPUT); 
  digitalWrite(9,LOW);
  delay(1000);
  digitalWrite(9,HIGH);
  delay(2000);
  pinMode(9, INPUT);
</code></pre>

<p>I don't know how it works, but it solves my problem.</p>

<p><a href="https://i.stack.imgur.com/KOcNr.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KOcNr.jpg" alt="enter image description here"></a></p>
 31192: <p>Near C6 and J15 you have 2 points.  You need to solder it.
Before soldering yon can hold wire on one of it (down pin , during code execution).</p>

<p><img src="https://i.stack.imgur.com/PjpiD.jpg" alt="1]"></p>
