<span id="docs-internal-guid-c15e9fd9-7fff-537c-ddf2-1938aca07829"><span>Electrical energy can not be separated from the name kWh Meter, a tool used to measure and record the amount of electrical energy usage has a shortage of kWh meters can not be monitored remotely how much energy is used, so it is rather inconvenient for PLN officials to check the use of electricity for postpaid customers. This research was conducted to design a prototype of a wireless electrical energy transmission system and design a wireless electrical energy recording system using the NRF24L01 wireless transmitter module and the PZEM004T kWh meter module. The design in this study uses the principle of electromagnetic induction to transfer electrical energy at close range, while to transmit data, the authors use the NRF24L01 module. Besides, the authors use the PZEM004T module to measure various magnitudes. Based on the results of observations and measurements of the design of the tool, the authors found that the transmission of electrical energy using electromagnetic induction is not effective for longer distances because the energy lost in the air is getting bigger. So this technology needs to be further investigated. Besides, the measurement of electrical quantities using the PZEM module has a small difference (under 2%) with measurements using a multimeter, so it can be said that the measurement with the PZEM004T module is effective. </span></span>

Electrical energy can not be separated from the name kWh Meter, a tool used to measure and record the amount of electrical energy usage has a shortage of kWh meters can not be monitored remotely how much energy is used, so it is rather inconvenient for PLN officials to check the use of electricity for postpaid customers. This research was conducted to design a prototype of a wireless electrical energy transmission system and design a wireless electrical energy recording system using the NRF24L01 wireless transmitter module and the PZEM004T kWh meter module. The design in this study uses the principle of electromagnetic induction to transfer electrical energy at close range, while to transmit data, the authors use the NRF24L01 module. Besides, the authors use the PZEM004T module to measure various magnitudes. Based on the results of observations and measurements of the design of the tool, the authors found that the transmission of electrical energy using electromagnetic induction is not effective for longer distances because the energy lost in the air is getting bigger. So this technology needs to be further investigated. Besides, the measurement of electrical quantities using the PZEM module has a small difference (under 2%) with measurements using a multimeter, so it can be said that the measurement with the PZEM004T module is effective

Groundwater quality is very much influenced by soil type, soil content, and water flow pattern in the soil. Dusun Salem and Randuacir are hamlets not far from the final garbage dump in Salatiga. This research was conducted to determine the condition of groundwater in Salam and Randuacir hamlets, Randuacir Village, Argomulyo District. The samples were taken as many as 19 wells and the sampling was done randomly by disproportional stratification. To determine water quality, the data from the measurement results of heavy metals [Copper (Cu2+), Manganese (Mn2+), and Zinc (Zn2+], chemical and bacteriological parameters of well water are compared with drinking water quality standards according to Government Regulation No. 82 of 2001 concerning Water Quality Management and Water Pollution Control. Meanwhile, the physical parameters are compared with the Regulation of the Minister of Health of the Republic of Indonesia Number 32 of 2017 concerning Environmental Health Quality Standards and Water Health Requirements for Hygiene, Swimming Pools, Solus Per Aqua, and Public Baths. To determine the level of groundwater pollution, the Pollution Index (IP) is used according to the Decree of the State Minister for the Environment No. 115 of 2003. Based on the results of the study, it can be concluded that: 1) Of the 19 wells in Salam and Randuacir hamlets, there are 3 wells (15.79 %) contaminated with Cu2+, Mn2+, and Zn2+, 2 wells (10.53%) were contaminated with Cu2+ and Zn2+, 6 wells (31.58%) were contaminated with Mn2+ and Zn2+, and the remaining 8 wells (42.10%) were contaminated with Zn2+; 2) Based on the pollution index (IP) of the 19 wells studied that are within a radius of less than 1 km and more than 1 km, all wells are lightly polluted (100%).

Video monitors traffic generally does not detect the speed, quantity, and length of passing vehicles. This research provides the design, manufacture, and analysis of vehicle detection system with computer vision technology using OpenCV library. The system can display the output of the number, speed, and length of the vehicle. The study was conducted using OpenCV as a library of C++ programming language. In this research tool used is a web camera mounted on the pedestrian bridge. Web cameras will record the movement of the vehicle at a certain distance. To detect the movement of vehicles, we need a background image. Background image was obtained by using the method of Time Average Background Image (TABI). Reduction of pixels between the background image with the image captured by the web camera will produce a vehicle is detected. The vehicles will be marked with a red box. The speed of a vehicle can be measured by dividing the distance traveled by the vehicle travel time of vehicles. This system has been successfully calculate the speed of a passing car with an error range of about 2.44 to 4 percent. The number of vehicles can also be calculated with an error of 26.7 percent, and the length of the vehicle can also be calculated with an error of 11%.

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