Hardware

Through the heart rate and visual convolution network of the bracelet, the current mood can be obtained by multi-modal calculation and analysis of the data, which can be converted into the corresponding red and blue signals to induce the engineering bacteria to synthesize odor substances, which can be released through the aromatherapy system to relieve the psychological pressure of users.

Overview

This project proposes to capture people's current facial expressions through facial recognition and obtain their current heart rate data through bracelet monitoring. The captured facial expressions and heart rate data were analyzed and processed in the background, and the current emotions such as anxiety and sadness were output as red or blue light signals, so as to stimulate the role of the corresponding promoters in Escherichia coli in the dark room, and induce the synthesis and release of odor substances such as linalool and phenylethanol by engineering bacteria. These odor substances will be released slowly through the aromatherapy system, stimulate people's sense of smell, mobilize the body's emotional regulation system, help people timely relieve some pressure in work and life, and promote the brain to actively deal with bad emotions.

1.Wristband heart rate monitoring

1.1 Principle

PPG(Photoplethysmographic) irradiates human blood vessels through LED light source, uses sensors to measure the attenuated light reflected by human blood vessels and tissues, records the pulsatile state of blood vessels and measures pulse waves. LED light is emitted to the skin, and the light reflected back through the skin tissue is accepted by the photosensitive sensor and converted into electrical signal, which is converted into digital signal by AD. Because there is blood flowing through the arteries, there is a change in the absorption of light. When the light signal is converted into an electrical signal, the changing AC signal can be extracted to get the characteristics of blood flow, and then get the pulse.

1.2 Operation demo

We use exercise bracelets for heart rate detection. The communication between the bracelet and the user is transmitted by the way of BLE (Bluetooth Low Power). The biggest feature of BLE is low energy consumption, its average power consumption can reach less than 10mA. Compared with classical Bluetooth, BLE also has the characteristics of fast transmission speed, long transmission distance and large broadcast capacity. After measuring the user's heart rate, the bracelet will broadcast the user's current heart rate through BLE. The phone picks up the heart rate and uploads it to the cloud for analysis.

1.3 Data Transmission

After the smart phone reads the heart rate data broadcast by Bluetooth, it uploads the data to the MYSQL database of the server for saving through HTTP GET request, and the PC can obtain the heart rate data through HTTP request.

2.Visual identity part

In the camera part of AI facial recognition, considering that our product is positioned more for desktop office environment, while not adding more hardware burden for users, we use the software to call the laptop's own camera function to capture facial expressions in real time and make calculation judgments with the authorization of users

3.Converting the corresponding expression recognition into light source signal

By combining the results of the bracelet and expression recognition, we get effective expression recognition results.We translate the different expression cases to the corresponding light source mapping cases, thus facilitating the engineering bacteria to start and activate the corresponding functions

The overall recognition flow is shown below：

(1) First, we call the laptop's own camera for user expression capture (after user authorization) considering the positioning office scenario and user hardware burden

(2) Then, the image containing the face will be transformed into a 48*48 matrix as the convolutional neural network input

(3) The algorithm convolutional neural network is used to compare the combined scores of different expressions of the database material

(4) The expressions with the highest scores will be displayed and combined with the bracelet results

We use Pulse Width Modulation (PWM) mode of dimming, by changing the duty cycle of the output voltage to obtain different light intensity illumination to meet the experimental requirements.

Schematic diagram of duty cycle

Duty cycle changes from 0 to 100

Test the output waveform in the laboratory

Output waveforms with different duty cycles

1.Red and blue control

We choose 2835 lamp beads as the light source for red and blue light, with wavelengths of 465nm, 660nm and 760nm respectively, operating voltage of 3.1V, single power of 0.5W, and luminous Angle of 120 degrees. The output control level of GPIO port of Arduino Uno R3 is used to control the LED on and off.

2.Lethal System

Our in-depth partners: HNU_China helped us to complete the functional verification of the lethal system. The specific experimental method can refer to the experiment part in WET Lab. As for the hardware design, we still adopted the mode of blue light intermittent irradiation to activate EL222 expression. In other words, 2 hours after irradiation of E. coli, 2 hours of shading treatment (to reduce the toxic effect of blue light irradiation on the bacteria, and at the same time to shift the chemical balance), so as to circulate for 8 hours. Subsequently, the bacteria lysed and died due to the large accumulation of BLRA toxic protein in E. coli.

3.Odour emission module

We use fans to accelerate palatalization, in the form of bladeless fans, the wind is gentle and the air supply area is small, and volatile substances are more conducive to blowing to the user. The wind blown out of bladeless fan passes through the internal air duct, there will be no violent wind impact, it is more gentle and stable。

3D Model

Future extends function

Music can trigger and affect people's emotions. Lighting often appears together as the visual language of music, which has a more multidimensional impact on people. The combination of light and music is emotionally powerful and can have a diverse impact on people. So we plan to add Audible and visual function to the hardware system to help regulate users' emotions.The following picture is our design of sound and light PCB board, with sound signal output port and light control signal output port.

1. Music

Music can help people shift their attention from the negative situation itself to something pleasant. Music can also directly act on the emotional hypothalamus and limbic system and other brain centers, to regulate people's emotions. Different music has its own corresponding emotion type. We can have a better effect by corresponding different emotions according to the emotion type of music. Therefore, we plan to add a music player device to the system, which will play different types of music according to the current mood and adjust the user's mood.

2. Light

We plan to add a part of color adjustable light belt on the surface of the device, which will emit light of different colors and intensities according to the current mood of users, and match with different light actions to achieve the purpose of adjusting users' mood. Different lighting colors and intensity have different effects on people's positive and negative emotions. Only by designing different lighting according to different emotions can our equipment play its maximum role.