A small RGB LED board that can be mounted on pinball playfields. The board uses neopixel LEDs (WS2812B), which can be chained using only three wires: power (5V), ground, and data.

The boards are panelized into 100mm x 100mm pcbs for easy and inexpensive ordering from jlcpcb.com (or other fabs). I recommend using their SMT assembly to populate the LEDs and the capacitors during manufacturing.

There are two pcb options: a stamp hole panel that easily breaks apart, and a nocut layout that must be cut manually later on.

The uncut pcb has a dense layout yielding 27 led boards (3x9). This is the most economical option, but it requires cutting the pcb manually later on, which is surprisingly difficult. The total cost, including the cheapest shipping option at jlcpcb was about $25 for five populated panels, for a total of 135 boards.

I tried a bunch of different options to cut the boards apart. The best one was using a mini table saw with a thin 4 inch diamond blade (Amazon carries these for ~$70 [link] , Harbor Freight has one for ~$40 [link]).

Scoring the pcb with a knife or scoring tool kind of works, but it takes a lot of work and a lot of long time. It's also easy to slip and mess up and the resulting breaks are not very clean.

I also tried using a scroll saw, but the boards are so small that the blade guard was often not able to hold them down.

A more convenient option is the stamp hole layout, where the boards are cut during manufacturing and can be broken apart easily.

The stamp hole panel yields only 21 led boards (3x7) due to the need for edge rails and a minimum cut width of 1.6mm.

Another drawback is that jlcpcb contacted me after reviewing my order to charge an additional $12 because the panel requires too much cutting time. This brings the total cost including shipping to $35 for 105 populated boards. Still a great deal overall and no mess cutting the boards yourself.

My actual preferred option would have been a v-cut panel, but jlcpcb does not offer SMT assembly for v-cut panels, as they may warp during the reflow soldering.

The photo shows the use of the pin-led boards in a Stern Stars pinball machine. Some connections use headers and dupont-style connector wires, while others were soldered. The connector wires are much more convenient. They make it easy to create the inital setup and make change later on.

Here is a short video of the boards in action. They are being driven by an Arduino Nano running the strandtest neopixel demo.

I used EasyEDA v6.4.7 to design these pcbs. It's a free software offered by jlcpcb that can be used online or downloaded and installed. Major benefits were support for the jlcpcb parts catalog to build the BOM and excellent support for panelizing (something that I couldn't figure out in KiCad).