This study aims to build a prototype of a prepaid electricity meter by using micro-controller ATMega 328 on Arduino Uno R3device. The prototype is used for counting and limiting the usage of electricity in a simple circuit. Through the research wehave developed the prototype of prepaid electricity meter device that has some functions such as: measuring the electricityusage, provide information about the rest of the quota, and cut off the electricity when the quota has been exhausted.Encryption and decryption method used to generate token is substitution method while the sensor used for input is currentsensor. Prototype testing has been conducted. Functions that want to be enforced has been reached and already evaluatedsuch as: calculating the electricity, insert token, translate token to number of the quota and expired day, decrements situationof quota, warning indicator, and final termination function when the quota has been exhausted.Kata kunci : KWH meter, mikrokontroler, ATMega 328, prototype
