Quoted from Ashram56:WS2812 ledstrips are very common, and very cheap on Aliexpress if you're patient (delivery can take some time).
Here are the ones I regularly use for my "gizmos":
https://fr.aliexpress.com/item/2036819167.html?spm=a2g0o.productlist.0.0.517a7893sRGbvb&aem_p4p_detail=202106110524345248356825853200001705205
A 5m roll of IP30 60 led/m is 20 dollars. It can be cut anywhere to the correct lentgh, just at the pad (which are spaced every 1.5cm).
To note:
- Each led can consume up to 60mA, so if you have 5m at 60l/m is 300 leds, meaning 9A. Granted, it's full white and full brightness, so in practice it's slightly lower, but this still means you need a dedicated 5V PSU
- You need to reinject power every 150 leds or so, as the current decrease on the power line of the ledstrip. For this application therefore it's one power input for each ledstrip.
- The IP class will determine the "cover" of the ledstrip, IP30 is "raw", IP60 should give you a transparent silicon rubber above the ledstrip, which I recommend as it allows to protect the electronics
- From what I understand of the pinball electronic design, it seems to be just a matter of duplicating the data signal from the pinball ledstrip to the external ledstrip. While not strictly "by the book", it is possible to drive two ledstrips with one signal without any additional electronic (which is what has been done here I assume). If one is very picky on electronic design, you should add a single input dual output buffer. If you intend to drive two additional ledstrips (rear and back), then it's recommended to add the buffer in any case (as this would mean driving three outputs from a single control signal).
Thanks for the info. What's a buffer? (In this context)