As most of you know, a significant number of computer enthusiasts use LEDs, thus regularly facing the need to calculate the required resistance, so they can choose the right resistor. There are many solutions that are designed to help enthusiasts with this, quite frankly, nontrivial task, like specialized online calculators and relevant articles, or you can just learn Ohm’s law (U = I * R) ;). Giorgos Lazaridis from PCB Heaven, who you may also know as the author of a custom Men Of War game controller, decided to help many novice enthusiasts with figuring out what type of resister would they need for their LEDs by designing a special paper-made LED Resistor Selector Dial, which anybody could make for themselves.
The main idea behind this fancy
origami device is that when you select the source voltage and the voltage of your LED, then it will show the required resistance for different levels of power. The whole device consists from a few paper discs with data dials printed on them, while selecting the voltages is done by rotating the disc. You can get the basic view of Giorgos’ LED Resistor Selector Dial in photos that are embedded in this post, but should you need more details about it, e.g. if you want to know how to make one yourself, then you should visit the corresponding post on PCB Heaven.
Source: PCB Heaven