Feedback on Schematic

I’m looking some feedback on this small PCB. I wanted to connect several of these boards with a wire connector similar to the “grove” connectors. It would be powered thru an Arduino Uno with the capabilities of going out to the Internet to obtain scores from When a goal is scored, the lights flash.

Single LED Board1.0a.fzz (7.0 KB)

Any feedback is much appreciated.



If you connect several boards, the second will see a resistor of 20k, the third 30k …
The light produced by LED will decrease with the number of boards.

If I have understood you idea, this is not what you want.

Furthermore, pins 1 and 2 of U2 are shorted. So this will not work at all.
Here is a suggestion:
Single LED Board1.0b.fzz (6.3 KB)

You understand my concept. I was trying to place the headers on the underside of the board. The program kept wanting to place a line on the connector which thought was wrong. (a net between post) so I placed it there.

I’m not an electrical wiz by any means.

I’ll look at the file you provided tonight after work.


My previous proposition had one header on top, the other on bottom.
Here is a version with both headers on bottom face.

Single LED Board1.0c.fzz (7.2 KB)

Thanks again Wali. Now you say I would need to increase the resistor on each of the boards as the number of boards increases.

Or is possible to have a centrally plugin area, like a Raspberry Pi to Grove Connector Interface Board

No, with the schematic I gave you, all boards will have the same resistor value.
Yes you can have a centralized plugin area, but it is not necessary: plug next board at the output of the previous one is OK.

The maximum number of LED is limited by the maximum output current of your Arduino.
Under 5V, a LED will sink approx 500µA with 10k resistor. Check Arduino datasheet to see how many LED can be powered by one Arduino output.

Check your LED datasheet, because it may require more current than 500µA (generally a LED require between 2 and 20mA).
In this case, you should reduce the resistor value.
And so, the number of LED you can connect on the output of your Arduino will decrease too …

One solution would be to use 3 pins connectors (0V, +5V and LED signal), and to amplify current with a transistor on your board.