I have an Arduino Uno and I bought a SIM900 GSM shield for it in order to create a simple security system that calls me up on motion.
I powered up the Arduino with an external power supply (DC 12V/2A). I also used a DC 9V/0,6A power supply. I got changed them between ths Arduino and the GSM shield. My Arduino Uno worked with both of them correctly after I disconnected the USB plug. Until now...
For now if I plug whichever power supply then my board does not turn on. It works only with the USB plug. I used my multimeter to check what could be the issue. Power supplys are OK. If I plug one of them into the board and measure the current on the 5V and the 3.3V pins I can measure 1,21 Volts on each pins. If I plug the USB the currents (Volts) are correctly appeared based on the pin current value (5V and 3.3V).
What could be the problem? I did not use these devices too much. Could have beeen there any problem with these power supplies that caused this injury to the board? I do not see any bad things on the board. The AMS regulator chip looks normal as originally.
What can I do? Should I throw the board away and buy a new one? I am afraid this will happen again if I use these same power supplies with a new board... Could I have messed up something?
Please help me. My coding is ready and I would like to place my device on a remote location but this issue prevents this.
As I investigated the problem further I suspect that the AMS 1117 5.0 regulator chip has an issue. If I replace it with a new one will it work correctly in the future using these external power supplies?
Can I use the 12V/2Amps for the GSM shield and the 9V/0.6A for the Arduino Uno board?
I don't know if I can help, but I do know that I do NOT like the barrel jack on the Uno. It recently ruined one of my projects, and I had to cut up an old USB cord to power the board off of 5V instead of the 7-15V that a barrel can put out.
Hopefully once you replace the chip you can just use the USB cord. Sorry mate
Thanks for the reply. Unfortunately I have to use external power because I am using a GSM shield that initiate calls and calls need more current that the USB port could provide. So I am forced to use DC adapter as 5V is not enough for the GSM shield. I would just like to be sure this will not happen again after I replaced that AMS chip.
Anyway thanks again for your comment.
szalaco:
Thanks for the reply. Unfortunately I have to use external power because I am using a GSM shield that initiate calls and calls need more current that the USB port could provide. So I am forced to use DC adapter as 5V is not enough for the GSM shield. I would just like to be sure this will not happen again after I replaced that AMS chip.
Anyway thanks again for your comment.
If the USB port cannot provide enough power to your project, then you don't need to bother using the DC jack. I cannot help you with the details, because my knowledge on this subject is not that good. But it has something to do with the heat dispensation of the AMS1117. The higher voltage you provide, the less current you can draw from it.
You did not specify the module you are using. There are multiple SIM900 GSM shields. Please post specifics. If you are using this one:
Then you can NOT power it directly from the Arduino but you will need an external power supply. The 5v ports of the Arduino can never supply 450ma (max current draw from the shield). Also you CANNOT use more then 5v adapter on the GSM shield. The specifications clearly state:
Power jack - connected to external 4.8~5VDC power supply.
Have to agree with stevenette about the 5.5 x 2.1-mm socket.
As connectors go, it's not good. It relies a lot on some springy metal to take up a lot of slack. I know that's how most connectors work in practice, but combine large tolerances with some dogey metal plating and it struggles.
This connector is almost niversal with plugtop AC/DC PSUs, but is no good for long term use.
I usually cut the the thing off and use a Molex header and receptacle on a DIY Arduino. What puts most people off Molex is that sooner or later you have to crimp. The Molex tool is prohibitively expensive, but this https://www.amazon.co.uk/universal-micro-crimping-crimppins-Engineer/dp/B002AVVO7K is one of the best of the copies. Makes crimping a breeze and a really secure connection
GSM shield can accept 5V-26V external power supplies theoretically. Anyway it works. But my Arduino Uno has the issue. If not the barrel jack should be used then how I should use that molex connector or others kind of connectors to the Arduino? Through VIN+GND pin? My GSM shield is connected from above to the Arduino so do I have to connect the power cables through of the shield? I cannot imagine the solution yet. I am starting to look for possible methods...
