Introduction
Deep pressure therapy (DPT) is a form of sensory stimulation that applies gentle pressure to the body to induce a calming effect. DPT has been widely used to treat anxiety, stress, and sensory disorders in children and adults, especially those with autism spectrum disorder (ASD). However, most of the existing DPT devices are either manual, bulky, or expensive, which limits their accessibility and convenience.
In this paper, the authors propose and design an automatic inflatable vest that can provide DPT with optimal pressure regulation and safety features. The vest is based on the commercial Squease vest, which is a lightweight and portable vest that can be inflated by the user using a hand pump. The authors enhance the Squease vest by adding a pressure sensor, a solenoid valve, and a microcontroller to create a feedback control system that can maintain the desired pressure level and prevent overinflation. The authors also develop a software interface that allows the user to set the target pressure and monitor the actual pressure in real time.
The paper discusses the development of the hardware and software components of the automatic inflatable vest, as well as the experimental results that demonstrate its effectiveness and reliability. The paper also compares the proposed vest with the existing DPT devices and highlights its advantages and limitations.
Hardware Design
The hardware design of the automatic inflatable vest consists of four main components: the Squease vest, the pressure sensor, the solenoid valve, and the microcontroller. The Squease vest is a commercially available vest that has an inner air chamber that can be inflated by a hand pump. The pressure sensor is a piezoresistive sensor that measures the pressure inside the vest and sends the signal to the microcontroller. The solenoid valve is an electromechanical valve that controls the air flow in and out of the vest. The microcontroller is an Arduino Nano board that processes the pressure signal and controls the solenoid valve using a pulse-width modulation (PWM) signal.
The authors connect the pressure sensor and the solenoid valve to the vest using T-junctions and flexible hoses. The authors also mount the microcontroller, the pressure sensor, and the solenoid valve on a 3D-printed case that can be attached to the vest using Velcro straps. The authors use a 9V battery to power the microcontroller and the solenoid valve.
Software Design
The software design of the automatic inflatable vest consists of two parts: the firmware and the interface. The firmware is the program that runs on the microcontroller and implements the feedback control algorithm. The interface is the graphical user interface (GUI) that runs on a computer or a smartphone and communicates with the microcontroller via Bluetooth.
The firmware uses a proportional-integral-derivative (PID) controller to adjust the PWM signal that drives the solenoid valve. The PID controller compares the actual pressure measured by the sensor with the target pressure set by the user and calculates the error. The PID controller then applies a correction factor to the error based on the proportional, integral, and derivative terms. The correction factor determines the duty cycle of the PWM signal, which in turn determines the opening and closing time of the solenoid valve. The firmware also includes safety features such as a maximum pressure limit, a minimum pressure limit, and a timeout function to prevent overinflation, underinflation, and leakage.
The interface allows the user to set the target pressure and monitor the actual pressure in real time using a slider and a gauge. The interface also displays the status of the vest, such as inflating, deflating, or stable. The interface uses a Bluetooth serial communication protocol to send and receive data from the microcontroller.
Experimental Results
The authors conduct several experiments to test the performance and reliability of the automatic inflatable vest. The authors use a digital manometer to calibrate the pressure sensor and a digital scale to measure the weight of the vest. The authors also use a human subject to evaluate the comfort and usability of the vest.
The authors measure the response time, the steady-state error, and the overshoot of the vest for different target pressures and compare them with the criteria for medical gas pressure (error no greater than 5%). The authors find that the vest can achieve the target pressure within 10 seconds, with an average error of 1.531% and an average overshoot of 3.125%. The authors also measure the power consumption and the battery life of the vest and find that the vest can operate for more than 8 hours with a single 9V battery.
The authors also ask the human subject to wear the vest and rate the comfort and usability of the vest using a Likert scale. The subject reports that the vest is comfortable, easy to use, and provides a calming effect.
Discussion and Conclusion
The authors conclude that they have successfully designed and developed an automatic inflatable vest that can provide DPT with optimal pressure regulation and safety features. The authors claim that the proposed vest has several advantages over the existing DPT devices, such as:
- It is lightweight, portable, and discreet, which makes it suitable for daily use and travel.
- It is affordable, as it uses low-cost and readily available components.
- It is customizable, as it allows the user to adjust the pressure level according to their preference and condition.
- It is reliable, as it maintains the pressure level within the acceptable range and prevents overinflation.
The authors also acknowledge some limitations and challenges of the proposed vest, such as:
- It requires a power source, which adds weight and complexity to the vest.
- It depends on the accuracy and sensitivity of the pressure sensor, which may vary due to environmental factors and wear and tear.
- It may not fit all body sizes and shapes, as the vest is based on a fixed-size model.
- It may not provide uniform pressure distribution, as the vest has only one air chamber.
The authors suggest some possible improvements and future work for the automatic inflatable vest, such as:
- Adding more air chambers and sensors to the vest to create a multi-zone pressure system that can provide different pressure levels to different body parts.
- Incorporating other sensory modalities, such as vibration, heat, or sound, to the vest to enhance the DPT experience.
- Conducting more extensive and rigorous experiments and evaluations with a larger and more diverse sample of users to validate the effectiveness and safety of the vest.
The authors hope that their work can contribute to the advancement of DPT devices and the improvement of the quality of life of people with ASD and other sensory disorders.
FAQ
How does the automatic inflatable vest provide a calming effect for the user?
The automatic inflatable vest provides a calming effect for the user by applying gentle pressure to the body, which stimulates the proprioceptive system. The proprioceptive system is the sense of body awareness and movement, which helps regulate the nervous system and emotions. By applying pressure to the body, the vest mimics the feeling of being hugged, swaddled, or massaged, which can reduce stress, anxiety, and sensory overload.
What are the challenges and risks of using the automatic inflatable vest for DPT?
The challenges and risks of using the automatic inflatable vest for DPT include finding the optimal pressure level for each user, ensuring the safety and comfort of the user, and evaluating the long-term effects and outcomes of the vest. The optimal pressure level may vary depending on the user’s preference, condition, and situation, and it may require trial and error to find the best fit. The safety and comfort of the user may depend on the quality and durability of the vest, the accuracy and reliability of the pressure sensor and the solenoid valve, and the user’s feedback and supervision. The long-term effects and outcomes of the vest may require more extensive and rigorous research and evaluation to validate the effectiveness and benefits of the vest for different users and contexts.
How can the automatic inflatable vest be integrated with other DPT devices or interventions?
The automatic inflatable vest can be integrated with other DPT devices or interventions to create a comprehensive and personalized DPT program for the user. For example, the vest can be combined with weighted blankets, sensory toys, music therapy, or cognitive-behavioral therapy to enhance the DPT experience and address the user’s specific needs and goals. The vest can also be used as a complementary or alternative option for DPT when other devices or interventions are not available or suitable.
How does the automatic inflatable vest compare to other DPT devices in terms of cost and availability?
The automatic inflatable vest is more affordable and accessible than other DPT devices, as it uses low-cost and readily available components. The authors estimate that the total cost of the vest is around $100, which is much lower than the commercial DPT devices that range from $300 to $3000. The vest is also easy to assemble and use, as it only requires a 9V battery, a Bluetooth connection, and a simple interface.
How does the user set the target pressure for the automatic inflatable vest?
The user can set the target pressure for the automatic inflatable vest using the interface that runs on a computer or a smartphone. The interface has a slider that allows the user to adjust the pressure level from 0 to 40 mmHg, which is the recommended range for DPT. The interface also shows the actual pressure in real time using a gauge.
Source:
https://ejournal.undip.ac.id/index.php/rotasi/article/view/61500/25328