Overview

We designed and made a portable IoT (Internet of Things) machine to provide a needed condition and produce the FitYo with the help of engineering bacteria. We open-sourced the machine. It also served the experiment by providing user-defined parameters, including light and temperature. It has an air pump and fluid pump to test the oxygen-controlled suicide switch and transfer the product. Multiple users can use any device with a WIFI and a browser to connect to the machine and control it at the same time.

We left the machine running for a long time to test its stability. With the feedback from users, we improved the temperature-controlling speed and safety. We added an automatic data recording program to the machine controlling page to provide more high-quality data to the modeling group. All the designs, including the 3D model, list of standard components, wiring, and the source codes are open-source by the link on our wiki page, which may help reproduction by other teams.

We also design some methods to improve the function of this extensible machine. We hope the concept of open-source equipment will benefit the whole of society.

Main Structure

The device looks like this:

Figure 1: 3D model of FitYo-Maker.

Figure 2: FitYo-maker from the front.

Figure 3: FitYo maker from the back.

It is mainly a two-layer box, with modules between the layers.

Figure 4: Modules overview.

Users can easily control the whole device without knowing every detail of the device through simple clicks on the website page. The MCU handles all the data through the web connection. It switches on/off the modules corresponding to the user command.

Thus, all that users need to do is nothing but switching the power on, connect to the website, and simply type some choices on the screen.

User Manual

1. Turn on the power

2. Connect to the WiFi named 'UCAS-China-MRM' with the password 'iloveyou'

3. Visit the IP address shown on the screen (192.168.4.1)

4. Choose a mode

5. Clicks the buttons on the web to switch on/off the modules. Set the temperature using the input bar (temperature from 0 to 80 centigrade)

Note: About the module status, 'ON' - Working, 'Off' - Stop Working

Details

After connecting to the machine and entering the control page, users can see the web pages on their devices. The page consists of three main parts: temperature control, module switches, and data recording.

For more information about design details of our device, please refer to the Technical Details page or download the sources at the end of this page.

History and Feature

Heating: Enhancement of Safety

After constructing the first machine, we sent the box to the users, provided them with a tutorial movie, and received feedback. We recorded the time needed to reach the temperature our users set. After knowing that the temperature rising was slow, we improved the placement of the PTC heaters. We made a heater dress that surrounds the FitYo container, speeding up temperature control in such a small device.

The heater requires a high current, which may induce fire hazards. We reduced the risk by choosing a new power supply with higher-rated power and a larger wire. After leaving the machine running for a long time and confirming that the box worked well without the risk of catching fire, we finally sent it back to our users.

Figure 5: Large wires.

Recording: Test and Improvement

We also made an automatic data recording function on the machine controlling the web page, making it simpler to provide accurate data to the teamers. Thanks to teamers who worked on modeling, we simulated the heat transfer and fluid mechanics in the box, analyzed some of the machine's behavior mathematically, and found some methods, such as PID control, to improve the functionality. More details are on the modeling page.

Figure 6: Data recorded on the web pages.

Future improvements

Multi-channel: more samples

To support controlled experiments, we designed a multi-channel mechanism. We hope in the future, the implementation of container array and image recognition on the machine will make experiments easier.

We designed the machine with 4*4 experimental container on the shaker. By assembling a multi-channel panel onto the box, we can test more values of parameters at the same time.

Figure 7: Rotator with a multi-channel panel.

In the future, we may add images acquisition and the automatic determination of the relative content of fluorescent proteins. The camera can be connected to the minicomputer and placed at a suitable position directly above the 4*4 square. An image recognition program implemented by OpenCV-Python in a minicomputer will process the image just taken.

PCB to arrange the connections

The design of the PCB will simplify the connection of wires. All modules can be assembled on the PCB and reduce the use of wire, which also help mass production of our machine when we bring meal replacements to the masses and make it a product in the market.

Figure 8: PCB with modules connected.

Sources

Open-source hardware makes some equipment accessible to everyone. Future teams may make progress based on our design.

Components

Main modules used in the machine are listed below.

Table 1.1 List of components

Components	Unit Price/$	Amount	Total
NodeMCU	2	1	2
Acrylic Panels	2	12	24
2-Relay module	3	1	3
8-Relay module	8	1	8
Mini air pump	3	1	3
Mini peristaltic pump	3	1	3
Blue light LED Strip	2	1	2
DS18B20 sensor	0.1	1	0.1
PTC Heater	0.6	8	4.8
12V power supply	10	1	10
12V - 5V module	3	1	3