Quantity   Component name
2 × Phototransistor Cheapest one from aliexpress, mine have flat head
2 × Led Fiber Optics / EmittersOld stock blue leds
10 × Resistors You'll need a some stock, or potentiometers to fidn the proper values
2 × OpAmps I use a TLC2272 because I hade it in stock
1 × Breadboard Electronic Components / Misc. Electronic Components
1 × Jump wires
1 × Small piece of wood
1 × Wood glue
1 × Transparent sheet Choose some that suit your printer
1 × A printer
1 × Some MCU or some APA 102, or anything you can write to with a data and a clock signal