Arduino doesn´t load sketch unless i press reset or is connected via usb to pc

Development Tools IDE 1.x
1

Hi
I Have a problem with my arduino it just won`t work if i upload sketch and connect it to power supply 12V or any other power supply(adapter 5V via usb,Vin 5V,12V,9V...)unless i hit reset button,then it works for a while.Yes for a while .I have my arduino connected to SIM800 gsm shield.I just want a simple switch to send me sms.I will upload code.I think i tried everything(tx to ground with 10k resistor,ground together...etc.
Please i need help,because i dont know what else to do.

gsmTextOnEvent_15.7.2019.ino (847 Bytes)

2

It's probably a power problem. Devices like your SIM800 often have very high momentary current draws while operating the radio. The barrel jack on your Arduino is connected to a voltage regulator that is fairly limited in how much current it can provide. It's fine to power your Arduino, but if you're also trying to power other devices through the voltage regulator then that can be problematic.

Which Arduino board are you using?

3

Thank you for your reply
Im using Arduino uno. Also im using power supply:for SIM800 5V 2A,for Arduino also 5V 2A(Vin)

4

Have you tried a different power suppy? a 5.25V wal wart wall plug should work, i\or even a battery box with at least 6V?