Team:UCAS-China/Hardware

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  1. Description
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  3. Proof of Concept
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• Hardware
  1. Hardware Overview
  2. Technical details
• Software
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  1. Model Overview
  2. Model for the Tea Pack
  3. Model for the Loophole
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• Hardware Overview
• Design
• Using process
• Demo video
• Technology Overview
• Future outlook

In order to make a user-friendly product for our ‘decaffei’ project, our team has made the following design about the intelligent coffee cup for hardware part. It can provide a reaction place for our coffeine-degrading enzymes and also provide hardware support for the development of our own app.

Design

Specifically, this is a cup or cup accessories used by consumers to detect caffeine content, which is based on the Internet of Things. It can detect caffeine content and directly decompose caffeine into beneficial theophylline, thus reducing caffeine content and conducting health monitoring. Figure 1 and Figure 2 respectively show the overall appearance and internal structure of our product, and the names of various components have been marked on the figure.

Figure 1. Overall structure of smart cup

Figure 2. Internal structure of smart cup (bottom view)

Using process

We hope to achieve the following functions. Coffee consumers who worry about excessive caffeine intake put mellow coffee with a large amount of caffeine on a coaster that can detect the volume of coffee, and insert the spoon with temperature sensor and magnet provided by us. When the temperature drops to a certain extent, the light of the single chip microcomputer flashes, and mobile phone reminds consumers to put the caffeine decomposition package into the coffee. The second picture is a caffeine decomposition package which is cylindrical and Slightly smaller than the cup with many holes. It contains two layers of immobilized enzyme and two layers of coenzyme. The consumer uses a spoon to attract the magnet in the decomposition box. After the two are connected, put the spoon and the decomposition box back into the cup together and then start converting caffeine to theophylline. After a period of time, the mobile phone reminds consumers to take out the spoon and decomposition box. In order to see how much amount of coffee they intake, consumers can use a spoon to take out a small amount of coffee and put it in the center of the blue electrode. We used enzyme electrode technology to specifically detect the content of caffeine. The enzyme used in the enzyme electrode also comes from the engineering bacteria we synthesized. After the coffee is added, the circuit on the right will start to detect the caffeine content. After the peak potential and current were obtained through scanning of the potentiometer, the caffeine content was calculated according to the formula summarized in experiment. The MCU will upload the temperature, volume and caffeine concentration to the mobile phone client end in real time through Bluetooth to provide statistics for our health detection program about sleep time and caffeine intake. After that, consumers can enjoy this cup of coffee with reduced caffeine content.

Demo video

Technology Overview

In order to be compatible with any type of cup, avoiding the process of transferring existing coffee to other cups when using the coffee kit. the kit consists of separate parts. We can also integrate all components on a small circuit board and put them into cup to get a tumbler.

The spoon has a temperature sensor and a pressure sensor to detect the quality. The volume of coffee consumed can be inferred from the amount of pressure change from the beginning to end.

Electrode detects the concentration of caffeine through the electron transfer between coenzyme Q0 and CDH and caffeine. The electrodes are disposable, that is, drink one cup of coffee, use an electrode. Similar to the blood glucose test paper on the market, we can reduce the cost of a single detection electrode through mass production and it can also be reused after improving the stability of the enzyme.

Referring to open source design on the Internet, we design a potentiostat. The principle is ：signals provided by the single chip microcomputer are transformed by the operational amplifier, obtaining potential output. Potentiostat and current measurement function together constitute this small electrochemical workstation. Connect three electrodes, set voltammetric cyclic scanning mode and measure peak current, then the caffeine content is calculated based on formula that is summarized previously.

The electrode is a three-electrode system. Graphene oxide, enzyme and necessary coenzyme, low-concentration polyglycol diglycidyl ether and low-concentration electron microscope stationary solution were used to modify the working electrode.

The Bluetooth communication module is connected with the wechat applet which can be improved to form an app in the future. Real-time operating system runs on the single chip microcomputer to schedule the tasks of temperature, volume, Bluetooth receiving and sending, and can also control the scanning process of potentiometer at the same time.

The caffeine decomposition package can be opened vortically and added into pieces of paper. Some papers contain enzymes linked by covalent crosslinking, and some papers contain coenzymes obtained by soaking. Two layers of enzyme paper are symmetrically coated with coenzyme paper to make caffeine react in the paper as completely as possible. Users can move the spoon up and down to increase the flow rate of coffee and increase the reaction rate.

The caffeine decomposition package is designed as a relatively hard structure, which can be compatible with another design of our team: filtering makes the coffee slowly pass through the immobilized enzyme, so as to fully react.

According to the design above, we have made a physical model. The following is the display of physical parts:

Figure 3. Overall display of smart cup

Figure 4. filter element

Figure 5. Caffeine detection electrode

Figure 6. Spoon embedded with temperature sensor and wires

Tips：

In Figure 3, the leftmost one is: pressure sensor that can measure volume change through detecting mass change, cup placed on the pressure sensor and spoon in the cup. On their right side are caffeine concentration detection electrode, circuit board used for generating scanning potential and measuring current (small electrochemical workstation), Bluetooth communication module and central MCU module.

For more information about technology, see "Technical details".

Future outlook

On the basis of designing, constructing and testing the first scheme and after discussion and investigation, we realize that there are disadvantages such as the integration of hardware circuit and the automation of operation is not high enough. In the future, if we want to put this scheme into commercial production, we can produce small integrated circuits and add temperature control switches. Therefore, we have designed the second smart cup scheme version(see Figure 11. and Figure 12.), which marks our second engineering period of hardware design, as shown in the Figure7 and Figure8:

Figure 7. Overall structure of the new scheme(Assembled)

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Figure 8. Overall structure of the new scheme (Disassembled)

Figure 9. temperature control valve

Figure 10. Caffeine concentration sensor at the bottom

After coffee is poured into the upper container, time is needed to cool down the liquid to a certain extent to prevent enzyme inactivation after entering the reaction column. When the temperature drops to an appropriate extent, temperature sensor controls the electromagnet to power off, then the electromagnet loses its attraction, causing the spring pulls the iron sheet to expose the round hole so that the coffee is able to pass through the reaction column containing enzyme (see Fig. 9). Users can add a piston to control the speed of coffee passing through the column through creating air pressure difference inside and outside the container. Our team also gave a mathematical model for this scheme. (see "modeling")

"box for placing circuit board" ,which is shown in Figure 8, contain batteries, Bluetooth devices and chips that have been integrated in sensor signal processing modules. This makes our cups smaller and easier to carry. The bottom layer is the container used to receive coffee after decaffeinated reaction, and the protrusion at the bottom is the caffeine concentration sensor (see Figure 10). We hope to make an electrode that can directly transmits electrical signals based on enzyme electrode technology, eliminating the steps of sampling operation in the first scheme.

In short, the design and production of this cup with reaction, detection, data transmission and other functions is one of the major tasks for our team in the future.

Figure 11. 3D print physical model 1

Figure 12. 3D print physical model 2

see more details