Error in Arduino Mega


For a school project we have the assignment to simulate the buoys of the Scheldt (The Netherlands) by night. Each group of buoys have their own light character. We wrote a script for the Arduino to have one character on one digital output. In total we have 17 characters divided by 27 digital inputs. (we only take 5 LED’s per I/O). The script was tested with 1 LED and each character was working like a charm.

Now the big problems are coming. Today we got together to assemble the LED’s in our sea charts. And when we connect more than 4 I/O’s to the LED’s, all LED’s stopped doing their character from the script and started flashing constantly. All LED’s did the same. It was like the Arduino was tripping or something. Once there where only 3 I/O’s connected, it worked normally after resetting the power supply.

Are we doing something wrong? Can the Arduino Mega not handle that many LED’s?

For us it seems like a wiring issue or something. The scripting was checked the day before, and the Arduino was working as it should with only 1 LED connected.

If somebody could give us some help, that would be really nice.

I think you need to research how much current is needed per LED. How much current one I/O pin can produce. Once you know those things, you'll have the answer to your issue.

Please reassure us that you are using the correct series resistors with the LEDs. :astonished:

Suggest you give us a schematic diagram or at least, photos taken in daylight so that parts can be seen. Check the instructions for posting.

5 LEDs per I/O sounds wrong to me. Very wrong - especially without any external driver hardware.