Here’s the instructions for building LED boxes to use primarily for the Determination of Planck’s constant, but there are many other learning benefits from building them yourself. LED box
It’s a powerpoint, so you can freely edit it.
I’ll be buying components in bulk for my classes and future workshops etc. If you’d like to order hassle-free “kits” through me, please get in touch (justin.palfreyman@gmail.com). They’re around £5-£10 each (depending on if you want battery packs etc).