Load Cell Sensors are transducers (transducers, electronic components that can measure physical quantities into electrical signals) that can convert the pressure by the load into an electrical signal. IC HX711 is a weighing module, which has a working principle of converting the measured changes in resistance changes and converting them into voltage quantities through the existing circuit. Load cell and HX7411 are used to obtain data of weight which will be compared with a commercial digital weight scale that the accuracy has been verified. In collecting data of weight, there are several calculation methods including the mean, modus, and median method. This study aims to provide test results for the three methods with different variations in delay. Delay is used to avoid errors in taking data from the sensor directly and also to provide pauses for the sensor in real time data collection. The test was conducted with four human subjects who have differences in body weight. The variation of delay used is 250ms, 500ms, 750ms, and 1000ms. The test results show that when testing variations in body weight with a delay time of 250ms, the mean method has the best results with a value of nmean = 2. In the 500ms delay test, the median method has the best results with the value nmedian = 3. In the 500ms delay test, the mean and median methods have the same good results with values of nmean = 2 and nmedian = 2. In the 1000ms delay test, the median method has the best results with a value of nmedian = 2. The results of the whole test show that the values of Nmean = 6, Nmedian = 8, and Nmodus = 2 which indicate that the median method is the method that has the best level of precision.

Classroom light intensity is one of the essential factors in the learning process. Several factors affect light intensity in the classroom, i.e., determination of classroom design, position of objects in the classroom, window design, shading devices, type of lamp, and type of lamp armature. The research aims to determine the effect of armature lamp type. The results of this research are expected to increase the efficiency of electricity costs and use the classroom optimal lighting system according to Indonesian National Standard (SNI). Two types of lamp armature used in this research i.e. LED tube armature and LED bulb armature. This research used E11-210 classroom in E11 Building of Electrical Engineering Department, Universitas Negeri Semarang with the size of 12m x 9m x 3.5m. Simulation in this research used Dialux Evo 9 software. The results of observations and simulations show that E11-210 classroom had not followed SNI yet, in 350 lux. Based on simulation results, it shows that using LED tube armature and LED bulb armature will get light intensity of E11-210 classroom that follow SNI 6197:2011. Simulation results show that the use of LED tube armature (Powerbalance Gen2 RC463B) in E11-210 classroom will increase efficiency of electricity costs by 27.81%. Meanwhile, the use of LED bulb armature (Luxspace Ace Acccent RS750B) in E11-210 classroom will increase efficiency of electricity costs by 33.96%.

Classroom lighting is one of the essential factors in learning process for students in a university. There are two types of lighting available to apply inside a classroom, i.e., natural and artificial lightings. This research aims to simulate classroom lighting management technology concerning Indonesia National Standard SNI 6197:2001 using Dialux software. The simulation result shows that the applied artificial lighting inside E11-210 room had not followed the standard yet, in 350 lux. The existence of both artificial and natural lightings has made E11-210 room were excessive in light intensity, despite successfully obeying the standard. This paper uses lamp power modification to optimize the light intensity efficiently without to infringe the standard. This paper also presents the potential benefit of implementing power modification in saving electricity usage costs for 56.94%.

The uniformity of daylight in the classroom contributes to indoor visual comfort in the learning process. A Classroom that has non-uniform illuminance and is unsuitable with 350-3000 lux can affect visual discomfort. This study aims to design a classroom lighting system using daylight and artificial lighting according to Indonesian National Standard (SNI) 6197-2011 to get visual comfort. The results of this study are expected to increase the efficiency of electricity consumption and to solve the visual discomfort problem followed by SNI 6197-2011. This research using E11-210 and E11-112 classroom Universitas Negeri Semarang with the dimension about 12m x 9m x 3,5m. Based on observation, the classrooms had an illuminance of more than 20,000 lux with a uniformity less than 0,6 in the afternoon. Simulation in this study using Dialux Evo software with replacing the layouts of lamp, type of lamps and armature, modifying power of lamp, and implementing dynamics blinds. The result shows that the simulation can solve visual discomfort corresponding to SNI 6197-2011. This paper also presents that LED Tube power modification from 21 – 25 watts can save electricity costs by 37.3%.

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