My Arduino Mega 2560 R3 burned :(

Hi guys, i'm doing my final project recently. And i'm using acs712, hc05 (9,10), ds3231(SDA,SCL) and sdcard module to the arduino mega. At first i was trying to check the sketch to the arduino via laptop USB and it was fine and nothing happened. But then, suddenly the arduino shutdown by itself (on and off automatically). I was shocked so i unplug the usb. Then my friend tried to plug 12V adapter to the barrel jack and it back to normal. On the next minute, the arduino burn and smoke came near the barrel jack.

I'm confused right now. Got some hypothesis, 1. that it was may fault not to use 1K+2K resistor to the hc05 2. Is it the current draw got it's limit? because i just read from some forum that SD Card module and The RTC got a huge current draw to the arduino?

I really need yourhelp!

That was the voltage regulator you fried. As the board is nice, I recommend you purchase a few of those modules and resolder them with care. The modules you list are not too high of current drain, but an SD card module (not listed) could exceed the 20ma per pin recommendation. Max for all is 200ma. If that VR fried and smoked, I would suggest you look close for a 5v to ground short that runs off the arduinio. I had a short on a LCD module because I stripped off too much wire and POP! If you're smart you are not soldering the headers of these modules like I did. I still tend to think you shorted it.

Thanks for sharing, I think I may pick up an HC05 for myself.

thankyou for your respond. but hc05, ds3231 and the mega that were broken. the sd card is fine. i dont know what to do

None of the peripherals are to blame, although you shouldn't tell your mother that you had the hC-05 on pins 9,10. The 1k/2k resistors are for the benefit of the 3.3v Rx on HC-05, not the Mega and their absence is not likely to be fatal to the former either. It sounds like something ruff'n'ready around the power input. If it ran OK with 12v in the barrel jack for a minute, it sounds more complicated than just a short. I can't see how anything is redeemable in that area, but you may still get some value by putting a regulated 5v on the 5v pin.

I would go 9V dc adapter .... rather than 12V. 12V is in the documented allowed range ... but a lot of people don't recommend it.

Everything that we say is a guess until you post a wiring diagram and/or schematic so we can see what is hooked up to where...

firdadwi: the arduino burn and smoke came near the barrel jack.

Thanks to Southpark, it has just dawned on me that you might have been over reacting. Megas get quite hot enough in normal operation with a 9v wall wart, and I certainly wouldn't want to use 12v. It may be that you just had a bit of dirt or a bread crumb toasting, and you haven't actually burned anything serious....