Automatization of Weight and Height Measurement Using Ultrasonic Sensors HC-SR04 and Load Cell Based on Arduino UNO at Integrated Services Posts (Posyandu)

Abstract


Introduction
Health is one of society's basic needs, which is the right of every citizen protected by the Constitution (Khariza, 2015), be it physical or mental health. Many factors affect human health, such as the economic, social, and physical environment and individual characteristics. Age can influence the body's immune system, especially cell-mediated immunity or what is commonly called Cell-Mediated Immunity (CMI) (Noviyanti & Sarbini, 2010). Children under five years of age (toddlers) are vulnerable to health and nutrition, while the immune ability of the elderly group and the speed of immune response against infectious diseases will decrease with age.
One of the health problems that are often found in toddlers is nutritional problems. Nutritional status in toddlers can affect several aspects. Malnutrition in toddlers harms physical and mental growth, hindering learning achievement (Rahim, 2014). Physical indicators (anthropometry) of undernutrition can be indicated by low weight and short body (less height at average age). The incidence of undernutrition or short nutrition has become a global nutritional problem (Rahayuh et al., 2016). For that, nutritional status needs to be known early on through health efforts, one of which is Posyandu.
The existence of Posyandu is vital in the community because it is a forum for community empowerment in transferring information and skills from officers to the community and bringing primary health services closer to the community (Zuniawati, 2019). The benefits of carrying out activities at Posyandu are health services for mothers and children, family planning (KB), immunization, nutrition control, and prevention of diarrhea in children. At Posyandu, routine measurements of weight and height are carried out once a month. One way to assess nutritional status in community groups is by measuring the human body, known as anthropometry, which is presented as an index associated with other variables. These variables include age, weight, and height (Fidiantoro & Setiadi, 2013).
Measuring instruments are tools that humans can use to assist in the process of determining a parameter. There are several measurement parameters, including height and weight measurements. Measurable variables such as age, weight, and height can be identified through analog measuring devices. However, most tools are still analog and done manually (Dwiyatno & Prabowo, 2017). Changing the measurement process from manual to automatic can make it easier for humans to carry out measurement activities. This research aims to create an automated tool for measuring weight and height using the HC-SR04 Ultrasonic Sensor and a 50 kg load cell based on Arduino UNO as a tool at Posyandu.
Previously, many similar studies have been carried out related to the automation of weight and height measurements, such as those conducted by Dwiyatno and Prabowo (2017) but using the Delphi 7 interface. For weight measurement, the load cell used is of different types of mass capacity that can be weighed, as in the study of Kusriyanto and Saputra (2016) using a Mavin brand load cell of the NA4 type with a capacity of 200 kg. The type is type GP2Y0A02YK0F. The advantage of this research with previous research is that the measurement results can be displayed on a PC (Personal Computer), and measurement data can be stored automatically. The sensors used can be found on the market as more affordable than other types.

Research methods
The research is divided into instrumentation system design, tool testing, and data processing. The system design of this instrument is generally shown in the block diagram in  Generally, a series of built systems include reading parameters, processing, sending data in Visual Studio applications, and storing data in Microsoft Excel. On reading the physical parameters, height and weight will be captured by the Ultrasonic Sensor, and the load cell is then converted into electrical quantities (analog signals). The analog signal is then converted into a digital quantity (digital signal) using the Arduino Uno processor. The digital value converted from the Arduino Uno will then be displayed using a 16x2 LCD. The data will be sent to a PC via a wireless network using the HC-05 Bluetooth module and displayed with an interface created with Microsoft Visual Studio software. The measurement results will be saved in a file in Microsoft Excel containing name, age, height, and weight measurement results. The electric current source of this instrument uses a 5V power supply obtained from a rechargeable battery placed on the battery shield and connected to a circuit scheme with a voltage of 5 V.
The design phase of this automated measurement instrumentation system is divided into four parts as follows.

a. Circuit schematic
The schematic of the automatic measurement instrumentation circuit can be seen in Figure 2, with the scheme consisting of the following: 1. Load cells 50 kg in as many as four pieces 2. HX-711. Module 3. Arduino Uno 4. Power supply 5. Ultrasonic Sensor HC-SR04 6. HC-05. Bluetooth module 7. 16 x 2 LCD Ulyanida S, Supriyanto A, Suciyati SW, and Junaidi, 2022, Automation of Weight and Height Measurement Using Ultrasonic Sensors HC-SR04 and Arduino Uno-Based Load Cells at Posyandu (Integrated Service Post), Journal of Energy, Materials, and Instrumentation Technology, Vol. 3 No. 4, 2022

c. Tool design
The tool design created is shown in Figure 4. The framework uses PVC pipe with a height of 1.12 meters to place the Ultrasonic Sensor as a height-measuring sensor. The footrest below is placed in a load cell coated with an aluminum box to measure body weight. In the middle is a box containing Arduino UNO, a power supply, a Bluetooth module, and an LCD as a temporary display of measurement results. Ulyanida et al., 2022/ J. Energy Mater. Instruments. Technol. Vol. 3 No. 4, 2022 Figure 4. Tool design.

d. Visual Studio Interface Software
Visual Basic is a programming language that is easy for beginners because it is a simple language that uses commonly used words (Wiliani & Fahmi, 2017). In this study, Visual Studio is used as a monitoring system application. The application is designed to display data in the form of distance and mass parameters and can be used to store measurement data in the form of Microsoft Office Excel files. The interface also provides a column for the name and age of the child to be measured to facilitate data collection to be carried out. The application receives the measurement results that Arduino has processed.
The next stage of testing the measurement instrumentation system includes calibrating the instrument's tools. Calibration is carried out so that the sensor measurement results are known whether the measurement value is valid according to the comparison instrumentation. The test data results are then used to calculate the percentage of relative error, accuracy, and precision. Tests were carried out on the LCD, interface applications made with Visual Studio, and data storage systems.
After testing the instrumentation, the system will be implemented to measure children under five at the Posyandu to find that the system is running well. Data collection was carried out on ten toddlers. The nutritional status of the measured children is also attached, reviewed based on the anthropometric standards used by the Ministry of Health, namely a review in terms of age, height, and weight.

Results and Discussion
1. Tool Realization. The realization of the automation instrument for measuring weight and height is shown in Figure 5. The instrument displays measurement data value output on LCD and PC with Visual Studio interface wirelessly. Measurement result data is saved automatically with Microsoft Excel. The instrument frame is made with a 112 cm high PVC pipe as a place for the Ultrasonic Sensor and an iron body as a load cell in the lower box of the instrument frame with a height measuring 35 cm x 35 cm. The middle box contains the Arduino Uno components, Bluetooth module, power supply, and LCD. Ulyanida S, Supriyanto A, Suciyati SW, and Junaidi, 2022, Automation of Weight and Height Measurement Using Ultrasonic Sensors HC-SR04 and Arduino Uno-Based Load Cells at Posyandu (Integrated Service Post), Journal of Energy, Materials, and Instrumentation Technology, Vol. 3 No. 4, 2022 Figure 5. Realization of automatic weight and height measurement instruments 2. Liquid Crystal Display (LCD) Testing The test program contains a command to display the instrumentation system name when the instrument is powered on. Then the LCDs are the measurement results obtained from the sensor, namely from the Ultrasonic Sensor and load cell. This test is carried out to ensure that the LCD can function properly and be used to display measurement values from Ultrasonic Sensors and load cells. The following LCD test results can be seen in Figure 6. Figure 6. The LCD shows the instrument name and measurement data 3. Ultrasonic Sensor Test Ultrasonic sensor testing against standard tools is shown in Figure 7. This action is needed to determine the level of error or error in the sensor used. The test is carried out by measuring the distance of an object with a flat surface using an Ultrasonic Sensor, then compared with measuring the distance of an object using a standard tool. The supporting media used are "GEA Medical" brand height measurement, LCD, power supply, and various objects whose height is known.
132 Ulyanida et al., 2022/ J. Energy Mater. Instruments. Technol. Vol. 3 No. 4, 2022 Figure 7. Testing of Ultrasonic Sensors against standard tools "GEA Medical." Height scales are mounted on a wall at 2 m from the floor. The height measuring sensor is assembled according to the design drawing on the instrument. The samples used were 15 children with a height range of 66,7-108.8 cm (adjusting to the child's height), with each measurement of the Ultrasonic Sensor repeated three times. The results of distance testing using Ultrasonic Sensors against measurement results using standard tools are shown in Table  1. The graph of the results of distance testing using an Ultrasonic Sensor to measurements using standard tools is shown in Figure 8. The percentage error of the Ultrasonic Sensor obtained is 1.09%, so the average percentage accuracy value obtained is 98.913%, and the percentage value for the precision of the Ultrasonic Sensor is 91.895. The results followed research conducted by (Akbar, 2015) which obtained an error value of 1.14% with an instrument as high as 200 cm, Ulyanida S, Supriyanto A, Suciyati SW, and Junaidi, 2022, Automation of Weight and Height Measurement Using Ultrasonic Sensors HC-SR04 and Arduino Uno-Based Load Cells at Posyandu (Integrated Service Post), Journal of Energy, Materials, and Instrumentation Technology, Vol. 3 No. 4, 2022 and measurements were made in the height range of 163-172 cm. The error value obtained is almost the same, with a difference of 0.05%.

Load Cell Testing
The load cell is used to measure body weight. This load cell is equipped with an HX711 module which functions as a valued reader for the load cell by converting the measured changes in the voltage resistance to be forwarded to the Arduino. The supporting media is a 5 V power supply, LCD, and a weight reference measuring instrument, a Xiaomi brand digital scale of the "Mi Body Composition Scale" type. The series of load cell testing on standard equipment is shown in Figure 9. The load cell to be tested is a unified system in which four load cells of type G with a capacity of 50 kg are assembled using the principle of a Wheatstone bridge. The load cell is connected to the HX711 signal amplifier module to the Arduino Uno. The linearity test mechanism between the load cell and the weighing scale is carried out to obtain accuracy and precision between the load cell and the reference scale. Linearity testing is carried out using a load cell given a load that has been measured previously using a reference scale with a range of 9-18 kg. Then the measurement was repeated three times. The test results between load cells and reference scales are shown in Table  2. The graph of the load cell test results against the reference body weight is shown in Figure 10.  2. Ulyanida et al., 2022/ J. Energy Mater. Instruments. Technol. Vol. 3 No. 4, 2022 = 1,0719 -1,0019 The percentage of the average value of the measurement error obtained based on the calculation is 1.40%. The percentage of average load cell accuracy is 98.6%. The results obtained following the previous tests on measuring weight with a load cell in the study of Afdali et al. (2018). The error value obtained is 0.96%, and the accuracy value obtained is 99.04 %. The result of the measurement difference is 0.08%.

Application Interface
This study's interface application (user interface) was made using the Visual Studio 2019 application on a PC (Personal Computer). The design of this interface application consists of a monitoring display and a data logger display. The monitoring display reads sensor values, as shown in Figure 12. Figure 11. Monitoring menu display made with Visual Studio. Figure 11 is a monitoring menu display consisting of the main menu form. The main menu form contains a page that displays the menus in the application interface. This program has one menu, " file", which consists of exporting data to excel, deleting data, and opening data. The data logger display displays sensor measurement data in tabular form. Measurements on the data logger table can be started by pressing the connect button on the "Connection" group box, where the data logger process will start, as shown in Figure 12. Then after pressing connect, the measurement date and time will start automatically. The indicator light that was initially red will turn green. The sensor value that is read will be displayed on the LCD and in the "weight" and "height" text boxes. After that, select the port and click connect so that the Arduino Uno is connected to the application interface. When taking measurements, the "measurement data" group box is filled with data on the person whose height and weight will be measured, such as name, age, and gender. Then the data logger will start running after the "connect" button is pressed, then the weight and height measurement values will appear. If a stable number appears, press the save button to enter the measurement data in the data logger. The data stored in the logger can then be saved to Microsoft Excel. However, the auto-save that was designed does not work. Storage is done by copying the numbers from the data logger to Microsoft Excel. If we want to restart the measurement and delete the previous data logger by Ulyanida S, Supriyanto A, Suciyati SW, andJunaidi, 2022, Automation of Weight andHeight Measurement Using Ultrasonic Sensors HC-SR04 andArduino Uno-Based Load Cells at Posyandu (Integrated Service Post), Journal of Energy, Materials, andInstrumentation Technology, Vol. 3 No. 4, 2022 pressing the " File " menu bar and then selecting the "delete data" button, then automatically, all measurement data in the grid view data table will be deleted.

Data Collection and System
Analysis Data collection and system analysis were carried out to apply the tool directly to the weight and height measurement of toddlers so that the overall performance of the instrument that had been made was known. Data collection was carried out at Day Care Al Muhsin Purwosari on August 24, 2021. The collection was carried out with toddlers as the object of measurement, as many as ten toddlers. The realized system is shown in Figure 13. Figure 13. Realization of automatic weight and height measurement system.
To start fetching data, the object to be measured stands on the load cell. Then the object's weight and height values will be read through the Ultrasonic Sensor above the object's head and the load cell on the lower footrest. Furthermore, the device is connected to the PC wirelessly using Bluetooth for data transmission to the interface application on the PC, and the height and weight measurement begins. In the application interface, the serial port and baud rate are selected according to the system's use. The COM5 serial port and baud rate in this system is 9600. After the connection is successful and the indicator light changes color from red to green, the value read by the sensor will enter automatically in the application interface. They were supporting data that needed to be included in the name, age, and sex of the toddler being measured. The system measurement results displayed by the interface application can be seen in Figure 14. Figure 14. The measurement results are displayed on the application interface. Figure 14 above is the result of measuring the weight and height displayed on the application interface. The measurement results on the system indicate that the interface application that has been made can read and display the weight and height values from the sensor correctly. The measurement value is also displayed on the 16 x 2 LCD, which is placed on the top side of the black box, which aims to make it easier for others to see the measurement results from the instrument. The display of measurement results by LCD is shown in Figure 15. The measurement results on the LCD are displayed correctly and follow the values displayed on the application interface. Then the measurement results are stored in Microsoft Excel 2016, shown in Figure 16. Ulyanida et al., 2022/ J. Energy Mater. Instruments. Technol. Vol. 3 No. 4, 2022   From this data retrieval, the height and weight measurement data obtained in tables that have been processed from the storage system are shown in Table 3 as follows.  Table 3 is the result of measuring the weight and height of 10 toddlers. The measured age range is 2-5 years, and the table shows a toddler's weight range from 9.17 to 18.48 kg and a toddler's height from 76.95 to 108.55 cm. Information on nutritional status in terms of TB (Height) for age and BB (Weight) for age in toddlers who are categorized based on a list of anthropometric standards of weight and height based on a list of anthropometric standards of ideal weight and height of toddlers in the Minister of Health Regulation (PMK). ) RI Number 2 of 2020.