Alarm System and Emergency Message from Wheelchair User Emergency Condition

When someone uses a wheelchair, there is still the possibility of an accident to the user, such as when the user suddenly falls down from the wheelchair or the user falls down along with the wheelchair. For notification of emergency conditions for wheelchair users, an alarm system is designed that can send messages to the intended mobile number. The system is designed using Wemos D1 mini, Ultrasonic, MPU-6050 and Proximity E18-D80NK sensors. The conclusion from the measurement and test results are: the value read by the MPU-6050 sensor is taken one axis for each direction when the wheelchair was falling down, for left falling down, for right falling down, for forward falling and for backwards falling down. The Ultrasonic sensor works well for detecting the presence of user’s legs and the E18-D80NK proximity sensor works well for detecting the position of the user who is sitting in a wheelchair. Receiving notifications through the BLYNK server works well, not affected by distance provided there is an internet connection connected to the device.


Introduction
The use of wheelchairs in society is widely used to help people who have difficulty walking on their feet, either due to injury or disability. This tool is not only available in hospitals but is also sold in general at health outlets in every area. So it is relatively easy for people who have difficulty walking to buy a wheelchair. There are various types of wheelchairs, manual, electric, and sport. However, the most often found in the general public is the manual type because the price is affordable and its use is practical for ordinary people. The manual type wheelchair is moved by being pushed another person or by the user's own hand. In its use, it is often found that the safety of wheelchairs is not perfect. There are still many emergency conditions that occur in wheelchair users, such as when the user falls down from the wheelchair or the user falls along with the wheelchair. The cause of these emergency conditions can occur because the user moves excessively or it can also be due to the condition of the user being tired or weak and the lack of supervision of the user. For notification of the emergency condition of the wheelchair user, a warning device or notification is needed to other people when the wheelchair user at the emergency condition and so they can immediately provide assistance.
Several literature reviews that have been carried out relating to wheelchair safety systems are smart wheelchairs that can avoid obstacles by using 8 proximity sensors and cameras (Yeounggwang Ji, 2013). Electric wheelchair to avoid obstacles using the HC-SR04 sensor where the wheelchair can detect obstacles less than 2m (Taizo Miyachi et al, 2016). The electric wheelchair safety system from impact uses 6 proximity sensors to detect obstacles (Darul, Muslimin, 2017). Automatic wheelchair with intelligent control mode and Wi -Fi placement system. A wheelchair specifically for users who have lowlevel visual impairment, by scanning the position of the wheelchair and controlling the direction of the wheelchair remotely (Manjunath, Gurukiran, 2018). From the reference review, what is being done is to maintain safety while using a wheelchair, whereas in the event of an emergency, a wheelchair user has not planned to report the emergency condition. Therefore, the purpose of this study is to design an alarm system for notification of emergency conditions for wheelchair users and send messages to telephone numbers that have been stored in advance.
The goal to be achieved is to produce a wheelchair alarm system that can provide notifications automatically when wheelchair user at emergency condition. The emergency condition is that the wheelchair user falls along with the wheelchair or the wheelchair user falls down without a wheelchair. So, further action can be taken from the notification recipient or the people around who hear the alarm sound. Note that readers are referred to published work [1], [2], [3], [4], [5], [6], [7], [8], and [9].

Research Methodology
This section provides research methodology that we use in this work.  forward without a wheelchair. In this case, the ultrasonic sensor will detect that there is no user in a wheelchair so that the Wemos D1 mini Wifi Module will send an emergency notification to the target phone via BLYNK server.

Block Diagram
The explanation of the system block diagram is as follows: 1. Wemos D1 mini is the main controller that functions to process all data and becomes communication from the device to BLYNK server to send notifications. 6. BLYNK server is used as an application to receive notifications from wheelchair users at emergency conditions.    for the expected data reading. Figure 5 shows the placement of the E18-D80NK Proximity sensor. The sensor is placed on the right side of the wheelchair which is used to detect the presence of the user while sitting in a wheelchair.

Flowchart
The flow chart used to detect the falling down position of wheelchair users with or without wheelchairs can be seen in Figure 6. sensor. If the IR and Ultrasonic Sensors detect a wheelchair user, the LCD will display the words "Patient is fine". Furthermore, if the IR sensor does not detect a sitting user and the ultrasonic does not detect the user's legs, then the buzzer will sound and perform the display number function. The display number function is to send a notification to the BLYNK server as an emergency condition which will display information telephone numbers that can be contacted on the LCD.
When the gyro function is run, it will detect the position of the wheelchair when it falls down to the left side, right side, forward side or backward side. If the wheelchair is dropped, the display number function will be executed and the buzzer will sound as a warning sign of an emergency wheelchair user and vice versa if it does not detect the falling down position, the LCD will display that the user is fine.

MPU-6050 Sensor Test Results For Falling Down Conditions With Wheelchairs
The test is carried out to get a value that can be used as a reference when the wheelchair is in a fallen condition and it is necessary to send a notification alert to BLYNK. The sensor has an X, Y, and Z axis that will read the degree value obtained when the wheelchair is dropped. The degree value obtained is recorded and used as a reference for the direction of falling the wheelchair. Please see Figure 7.    Table 3. In accordance with Table 3 if the value of the axes is more than or less than the predetermined value, the wheelchair is considered to have fallen and wemos sends an emergency warning.

Down Conditions without the Wheelchair
The test was carried out with a user sitting in a wheelchair and performing an emergency fall without a wheelchair. Two Ultrasonic sensors on the right and left sides of the footrest and Proximity E18-D80NK on the right side of the wheelchair will detect Both sensors will send an unsafe signal when the ultrasonic sensor detects no user's foot or foot object and the Proximity E18-D80NK sensor on the right side also detects no thigh object from the user. The test results can be seen in Table 4.

Notification Delivery Test Results
The test aims to find out how far the recipient of the emergency warning can receive notification of an emergency message from the location of the wheelchair user.
Notifications are sent by the Wemos D1 mini Wifi Module and utilize the BLYNK application platform as a recipient of emergency warnings for wheelchair users. Testing is done by turning on BLYNK to receive notifications.
To test the mileage for sending notifications, it is carried out as follows: the device that receives the notification of an emergency is placed in a predetermined location, then a test of receiving the notification of an emergency is carried out. The wheelchair was placed on the Kalijudan campus of Widya Mandala Catholic University Surabaya, which is located in Tambaksari District in the East Surabaya area. The results of sending and receiving notifications can be seen in Table 5. From the above test, it can be concluded that the user can receive emergency notifications in all places with the condition that the device must be connected to the BLYNK server and connected to the internet.

Conclusion
The conclusion from the measurement and testing results are as follows: a. The value read by the MPU-6050 sensor is taken one axis for each direction when c. Receiving notifications through the BLYNK server works well, not affected by distance provided there is an internet connection connected to the device.