Security at the door is very important for everyone. because the door acts as access to enter or exit a private room. Therefore, the key as a door security plays an important role in implementing the security system. With the frequent occurrence of key loss and also the rise of increasingly sophisticated crime rates in breaking into or destroying conventional keys, it becomes a thought for the author to develop a security system that is more private in nature. That is by using an application that is expected to be a security in the form of a password which will certainly be more profitable. The design of this tool is made with Arduino as a processing center and a servo motor to function to move the doorlock. The next stage Arduino will give a command to the servo to open the door. Only certain people who have access passwords can open doors in rooms that use voice recognition. Meanwhile, those who do not have an access password will not be able to unlock the door in the server room. So that the design of a smart door lock tool that uses Arduino-based voice recognition will provide a more computerized level of security and access

The human body requires sufficient oxygen levels for daily life, so it is important for humans to maintain oxygen levels in their bodies. Good oxygen saturation will facilitate the distribution of substances in the body, red blood cells carry oxygen from the lungs and are distributed throughout the body. It is very important for humans to keep oxygen within normal limits. Excess oxygen in the blood or hyperoxaemia: above 120 mmHg. The normal limits for oxygen levels in human blood are between: 75-100 mmHg. Lack of oxygen or hypoxaemia is less than 75 mmHg. A blood oxygen level below 60 mmHg indicates a very severe blood deficiency and you need supplemental oxygen. The design of an oxygen saturation monitoring tool through the Thingspeak server with a max 30100 sensor based on nodemcu 8266 aims to make it easier to monitor oxygen levels in the blood so that it can take early anticipation to avoid unwanted things. The design of this tool is equipped with monitoring using a Thingspeak server that can be connected to the internet or WIFI so that we can do it when we are there. This blood tool is designed using a MAX 30100 sensor as an oxygen detector which is clamped on a finger and then connected to NodeMCU 8266. After waiting for a while the sensor detects oxygen levels < 80% >, 100% NodeMCU 8266 sends data to the LCD and Thingspeak. On the Thingspeak server we can observe the oxygen levels in our bodies. We can use this tool far away so we don't need to go to the hospital or health center to measure the oxygen saturation in our bodies.

The charging device usually uses a transformer and a diode bridge. Charging the battery is called direct charging. Because it does not have a safety for the battery it can cause heat to the battery. But over time, this is no longer effective, this work can be done digitally using a microcontroller.. However, this tool is still not perfect because at the time of testing it cannot be set, sooner or later, the charging is to cut time efficiency and there is no indicator that states that the charging is full or not. Therefore, based on the description above, the researcher aims to make a smart charging accumulator based on the Arduino Uno microcotroller that is smarter, more efficient and can be used easily, with the advantage of having a tap changer on the transformer that functions as a regulator of the output voltage. as desired and piezoelectric alarm as an indicator if a full charge or there is a problem with the equipment itself.

The vital capacity value of the lungs is very influential with the health of the human lungs because with the results the value of the vital capacity of the human lung can be diagnosed as normal or abnormal of the lungs. This study aims to make a means of detecting respiration gas flow rates in humans using an arduino uno-based YF-S201 flow sensor. From the results of data analysis of respiratory gas flow in adult male breathing with ages (20 years - 30 years), (30 years - 35 years), (35 years - 45 years) and (45 years - 50 years) as many as 15 users. there is an error of 3.86%, the value is generated from comparing the output of the equipment made by researchers with other tools of the brand Spirolab with as many as 15 users of different height and age. From 15 different users there are 2 users with abnormal lung conditions and 13 other users with normal lung conditions. The result of this error occurred because of the 15 users who were less relaxed when exhaling and breathing.

The charging device usually uses a transformer and a diode bridge. Charging the battery is called direct charging. Because it does not have a safety for the battery it can cause heat to the battery. But over time, this is no longer effective, this work can be done digitally using a microcontroller.. However, this tool is still not perfect because at the time of testing it cannot be set, sooner or later, the charging is to cut time efficiency and there is no indicator that states that the charging is full or not. Therefore, based on the description above, the researcher aims to make a smart charging accumulator based on the Arduino Uno microcotroller that is smarter, more efficient and can be used easily, with the advantage of having a tap changer on the transformer that functions as a regulator of the output voltage. as desired and piezoelectric alarm as an indicator if a full charge or there is a problem with the equipment itself.