LED Tester Also Calculates Resistor For Target Voltage

https://hackaday.com/2023/12/02/led-tester-also-calculates-resistor-for-target-voltage/

https://hackaday.io/project/193787-how-to-make-arduino-led-tester-resistor-calc

" The device is very simple to build, and consists of several components:
 - Arduino Nano microcontroller
 - 16x2 LCD Display with I2C communication protocol
 - 7 Resistors
 - capacitor
 - and four Buttons"