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I have recently downladed BlinkyTape board project form GitHub repository.
Everything seems clear except R3 value which is not mentioned anywhere.
I suppose a 330ohm could be suitable but every contribution will be appreciated.
We use 200ohm in production. It's not critical unless you have a long (>1m) wire between the board and the LEDs.
edit: correct the value
Thank you Matt I'll follow your answer.
I'm exercising on advertising signs 2.0.