Hi,
I have an Arduino Mega 2560. I'm pretty sure its original. I was working on a project and realized that the ON LED was half blinking or completely blinking. I knew that was not healthy. I've unplugged it all and left only the USB cable but the ON LED remains randonmly blinking. Its color is RED and I'm not sure if its supposed to be green, I don't remember. I was feeding the Arduino with a pretty stable 12v power source.
How can I interpretate this LED power blinking? is there any documentation about this? Thanks a lot.
The ON led should be permanently on, not blinking or whatever.
What was all connected and how was it wired?
What is the label next to the LED ?
On occasion people have misread the label and it has been the led that can be defined by the sketch/user.
ballscrewbob:
What is the label next to the LED ?
On occasion people have misread the label and it has been the led that can be defined by the sketch/user.
Its a led and it says "ON" below. Its over de reset buttom.
sterretje:
The ON led should be permanently on, not blinking or whatever.
What was all connected and how was it wired?
I've attached a diagram of how it looks like. I had replaced the LCD for a 4x20 one.
I'm not sure if I commited a mistake. I used the Vin pin to feed a 7805 and then to switch a LED lamp using a relay shield. The whole system is powered with stable 12v power supply. Maybe 12v was too much?
Is the 5V on at a nice steady level? If not you have 5V regulator damage, or perhaps the reverse polarity protection diode is going bad.
CrossRoads:
Is the 5V on at a nice steady level? If not you have 5V regulator damage, or perhaps the reverse polarity protection diode is going bad.
It marks a steady 4.84v at the 5v line; but meanwhile, the ON led blinks or its brightness fails from time to time. One has to wait for like a short period of time for it to start happening.
Sorry the question but ¿was this "ON" LED green? or it has been always red?
Is there a way to know if this is caused by the reverse polarity protection diode?
Thanks a lot!
I think that the problem is with the power supply. First disconnect all the components like LCD, Realy and other sensors. And then power the board and check. If it powers on normally, then the problem might be with the power supply which isn't sufficient for the components. Or you should use a seperate power supply for other components. I am not saying that the problem is with the 12V supply, but the 5V regulator is taking too much load because of other components. Use a seperate power supply for the sensors and don't forget to connect every sensor's ground pin to the Arduino.
...Arnav
Those "breadboard" power units have quite a low current capacity.
Popped three of them and gave up using those in favour of the buck boost modules.
ArnavPawarAA:
I think that the problem is with the power supply. First disconnect all the components like LCD, Realy and other sensors. And then power the board and check. If it powers on normally, then the problem might be with the power supply which isn't sufficient for the components. Or you should use a seperate power supply for other components. I am not saying that the problem is with the 12V supply, but the 5V regulator is taking too much load because of other components. Use a seperate power supply for the sensors and don't forget to connect every sensor's ground pin to the Arduino.
...Arnav
ballscrewbob:
Those "breadboard" power units have quite a low current capacity.
Popped three of them and gave up using those in favour of the buck boost modules.
The problem persists using nothing but an usb cable to feed the mega.
alexokaban:
The problem persists using nothing but an usb cable to feed the mega.
And therin lies the problem !
With all those extras I would not be surprised if you are trying to draw more than the mega can support.
Relays alone can draw close to the limit as is often seen when people try to run more than two / three relays with just the board supply.
They can also draw close to the limit for those breadboard supplies and thats BEFORE you add anything else.
USB 1.0 2.0 can only supply 500 mA some USB 3.0 can supply more than that but not all.
Add together all your components and I would not be surprised if you were close to or een OVER the 500 mA.
I would seperate and limit the MEGA supply and feed to the barrel jack around 7-10 volts.
I would then feed the other items as required with 5.5 volts and enough current to accomodate ALL the items.
ballscrewbob:
And therin lies the problem !
With all those extras I would not be surprised if you are trying to draw more than the mega can support.
Relays alone can draw close to the limit as is often seen when people try to run more than two / three relays with just the board supply.
They can also draw close to the limit for those breadboard supplies and thats BEFORE you add anything else.
USB 1.0 2.0 can only supply 500 mA some USB 3.0 can supply more than that but not all.
Add together all your components and I would not be surprised if you were close to or een OVER the 500 mA.
I would seperate and limit the MEGA supply and feed to the barrel jack around 7-10 volts.
I would then feed the other items as required with 5.5 volts and enough current to accomodate ALL the items.
I'm sorry, I may have expresed myself wrongly.
There is nothing connected to the MEGA. I took it all out.
The MEGA is only powered via USB. And the ON LED blinks after a while, which it never did before.
Again the scenario is just an empty MEGA plugged through USB cable.
Thanks
I've been using the mega with the blinking example. As it seemed working fine I plugged the whole circuit again and its working fine too. No LED power issues. I've decreased the Vin to 10v as recommended. Thanks a lot.
Please close, I don't know how.
