Have I fried my Arduino Pro Mini?

Development Tools IDE 1.x
1

Hello, I tried to power up my relay board, but i guess I did something wrong.

I put everything together as shown in attached picture.

826×468 59.5 KB

Right now I can connect to PC and program my pro mini with IDE ,but for example now when I write "blink" program to it , on board LED blinks as usual , but if I connect another LED to any of the pins, LED is very very dim, almost can not see at all when it is HIGH.

What I have fried? Is there a way to fix it? Or my mini pro ir dead :frowning:

P.S. 3,3 V mini pro. / HL-54S V1.2 (4 Relay Module)

arduino.jpg
arduino.jpg826×468 59.5 KB

2

If the 4 Relay Board has SRD-05VDC-SL-C on the relays, then this is a 5V powered board and PSU2 needs to be 5V.

Also, GND on the MiniPro should not be connected to VCC on the Relay Board.

Overall, your grounding is incorrect and needs to be resolved ... I can provide proper connections to use the full opto-isolation feature of the relay module after the exact part number on the relay is verified.

For a 12V Relay Board, this is how the relays would be labelled:
EDIT:

Connections for opto-isolation are the same as for the 8 Relay Module shown here:
http://forum.arduino.cc/index.php?topic=302601.msg2106189#msg2106189

3

dlloyd:
If the 4 Relay Board has SRD-05VDC-SL-C on the relays, then this is a 5V powered board and PSU2 needs to be 5V.

Also, GND on the MiniPro should not be connected to VCC on the Relay Board.

Overall, your grounding is incorrect and needs to be resolved ... I can provide proper connections to use the full opto-isolation feature of the relay module after the exact part number on the relay is verified.

For a 12V Relay Board, this is how the relays would be labelled: [mg]Imgur: The magic of the Internet
EDIT:

Connections for opto-isolation are the same as for the 8 Relay Module shown here:
relay module board, do I need resistor and transistor ? - #4 by dlloyd - Motors, Mechanics, Power and CNC - Arduino Forum

I ordered 5v, but get from china - relay board with 12V on relays , so 12V PSU is correct, but the my arduino wiring was wrong.

My main question - what is fried on my mini pro?

do I need to change mega328 or some other component on the board?

4

Is there a place where I can buy surface mount Atmega328 cheap?

mini pro from china 2,80 $ , only surface mount Atmega328 3$ , WTF? :smiley:

5

Mouser.com, $3.43
No Results Mouser

prices drop with quantity, down to
$1.85 if you buy 2000.

6

Is it 100% sure that atmega is fried?
or maybe some sort of voltage regulator?

7

:smiley: miracle just happened and my mini pro start to work again ... happy,happy,happy...

what was the problem? same sort of polyfuse?

8

Connecting an LED directly to an output pin will probably always be kind of dim... Those pins don't have much drive current. The LED lighting up at all is an indication that you're getting some sort of voltage, which is better than nothing.

Likely nothing wrong all along. Congrats!

9

I do not know , but to my 3.3v arduino w/ digital pins - LED blinks pretty bright.