“A hand held LED tester and calculator that can measure the forward voltage drop and determine the value of the current limiting resistor.
Around a month ago, fellow Hackster Mirko Pavleski published his Arduino LED Tester + Resistor Calculator project. This seemed like a useful project to add to my toolbox. I decided to redesign it to reduce its size and also make it portable. Also some of the features like showing the code for the Jaycar Electronic shop wasn’t very useful here in Australia so I modified the code to show standard resistor wattages.
Circuit
The first change was to replace the Arduino Nano with a ATtiny1614 microprocessor. This processor uses very little power and is ideal for a battery powered system. It will easily run on the 3.7V to 4.2V outputted by the LIPO battery. Also the 1602 LCD screen has been replaced by a 128x64 0.96in OLED screen. This helps reduce the size of the unit as well as provide a more detailed display. Finally the four switches are configured as a D-Pad to make adjusting the voltage and current more compact.”