Research has been carried out for the manufacture of a motor vehicle engine speed limit controller based on the level of oil condition based on the ATMega328 microcontroller. The method used is to read the pressure at different temperatures and certain rotations, if the pressure is too low then the program will determine that the oil condition is bad or it is time to change it, when the oil or lubricant has been determined that the condition is bad then the indicator light will light up. and the maximum engine speed limit will be cut to 6000 rpm so that the engine will not be able to be used for rotations above 6000 rpm. Cutting the engine speed limit has the aim of preventing the engine from being forced to work at too high a speed when the oil is in bad condition so that the engine components will last longer, besides that the indicator also serves as a reminder that it is time for the vehicle to need an oil change.

Measuring the responsiveness of the proximity sensor on a Samsung smartphone at the Teuku Umar Samsung Service Center has been carried out. The proximity sensor used in smartphones is a photoelectric proximity type with diffusion type, where it works using a light sensitive element called a receiver. The measuring method is to use a barrier board that is moved closer to the smartphone from a certain distance until the sensor is 1 and measures the distance between these barriers using a ruler or ruler which is then recorded, so that the maximum distance of the sensor response is obtained. From the results obtained, it can be explained that every year for the same class it has an increase, although not too significant, whereas if it is reviewed from the class between the lowerclass series and the upperclass series with the same year, it will have a more significant difference.