Team:GreatBay China/Applied Design


Design Concept

(After re-evaluating the criteria and judging feedback, we combined the hardware and product design pages.)
Nepetalactol, feral cats, and synthetic biology — three things that look bizarre and irrelevant if we put them together — can actually be mixed and fuse an unprecedented solution to an real world social problem. With creative ideas and massive research, we are confident that our applied design can assist traditional methods dealing with the feral cat problem, and the we envision a promising potential for this product to infiltrate our community creating a mutual positive lives for both cats and human.

Figure 1. Three elements of our product design

From lab to factory

— how our project naturally flows to our product design and how we obtain the product

Figure 2. Overview of the process of fermentation

GreatBay_China had succeeded in producing nepetalactol in laboratory, yet the current production level is not very high, future improvement such as continuing knocking out genes and choosing the optimum strain can enhance it greatly. The next step is to transfer the molecules from tubes to applicable and safe containers. We questioned researchers specialised on fermentation in Bluepha Lab, and through some discussion, a process is put forward.

Figure 3. A review of our product design(1)Genetic Modified E.coli and Yeast to produce nepetalactol(2)Fermentation via conical flask or fermentation cylinder (3)Extracting essential oils by using a suitable organic phase (4)Aids in attracting cats by volatilisation of essential oils(5)Our Hardware Design,the ”Kitty Wonderland“

From the test tubes we transfer the co-culture solution to a conical flask allowing the bacteria and yeast to grow. Then we transfer the mixture to a fermentation tank for good fermentation. After a period of time, we are able to extract the desired molecule from this solution. Instead of the common extraction method used in laboratory, which includes adding oil to solution in test tubes, we intend to directly add oil to the fermentor and carry out the extraction in a large scale. This is more efficient, apparently, compared to the laboratory method. We realised that large-scale fermentation using engineered bacteria and yeast in industrial level is very different from labotary conditions, particularly in terms of the growth states. So before our production is applied to large scale, more explorations and studies are required. The experts on fermentations are very interested in our strains, and suggest that they are able to provide technical support to us in later improvements.

For application, our product also perfect flows in. After we obtain an amount of nepetalactol, we can add them into small petri dishes inside the cat shelter we designed— Kitty Wonderland. The design incorporates a petri dish that are easily accessible so we can fill and replenish it in the most convenient way. Besides, a fan in the shelter allows the scent to be better diffused. Safety concerns are addressed by a number of details in design and you can check our "Hardware”.

Numerous evidences show that nepetalactol is very effective at attracting feline animals. For safety consideration, before we broadly implement the shelter, we will cooperate with animal rescue team and animal protection association in government to run a few trails. For example, the concentration of nepetalactol should be determined by the result of observation.

This video shows how we came up with the idea of building our ‘Kitty Wonderland’ and how it’s connected to our wet lab project.

GBC Documentary P2

To know the specific idea and the history of the development of our project, please check the next episode. The previous episode is about stray cat problem.

From factory to your doorstep

— how our product addresses problem, benefits current process, and influences our live positively

Figure 4. Food and Trap: a traditional method of catching feral cats. Image from

Our project is closely intertwined with the human practice we have done. In particular, our synbio product offers an unique solution to the feral cats issue. From our interview with some animal rescue teams in Beijing and HongKong, we learnt that the most difficult thing to do in animal rescue is to find and trap feral cats. This is reasonable because most feral cats are very sensitive so they resist help from many volunteers. Feral cats also have a different lifestyle to us human so it requires a lot of effort to catch them. Last but not least, traditional method requires much labour to cover the different area of cats, which is costly, time-consuming, and ineffective. From our investigation we discovered that other potential solution includes attracting cats by food, or setting up trapping devices. Although these methods have some effect, their efficiencies are questioned. Trapping devices are especially doubted in ethical ways. As a result, we are confident that a cat house, surrounded by the scent of attractive nepetalactol, addresses the problem more effectively than other solutions.

Instead of us trying so hard to hunt the cats, why not let them come happily to us?

Figure 5. NTR is the most scientific and effective approach toward feral cat problem today. Image obtained from

If implementation of our cat shelters are successful, it will merge perfectly with the rescue processes of many rescue teams. In fact, it will make their job easier and save them more time. As mentioned in our Integrated Human Practice, an sophisticated rescue process called TNR (Trap-Neuter-Return) is used to deal with the feral cats problem. Our product will facilitate the “Trapping” step. With the sensor in the cat shelter, a message will be sent to local volunteers’ phone and they can check the connected camera image and see whether it is really the cats that triggered the signal. Once confirmed, they will be able to close the door of a cat shelter on their phone, temporarily trapping the cat. And the volunteers can then come to the cats. Apart from this, we plan to put a automated food-feeding machine inside the shelter so “Kitty Wonderland” can provide a relaxing and cosy environment for cats. Later on conducted an online interview with one rescue team in Beijing. The leaders, Ms. Fenghua Li, Dachui, approved our design surprisingly. From our activities in Public Engagement, we received designers and cat-lovers’ advice on some particular design of the cat shelter that will be more friendly to cats. See our Public Engagement for more details.

Figure 6. Members of GreatBay_China doing random interview with local people about opinions on our design.

In addition to the supportive application to rescue team, our product design will also have a positive implication to the local community and people. From direct interview in our neighbourhood, the idea of a cat shelter were not rejected or doubted, however, many people appreciate it. Some people pointed out that, this design will accelerate the rescue of street cats, therefore reducing annoying cries of them in the night. On top of that, in order to picture a comprehensive impact our product could bring to the whole society, at September 1st, we brought the tester to an adopting festival hosted by ‘Shenzhen Pet League’ in order to seek opinions of the wide public and allow a reasonable inference on how our product would impact the society. By interviewing passengers and other participants on the idea of placing our KW in communities, we found out that most people consider this activity with approval, while others’ main concern is the safety of cats, which we have been working on to assure for a long time.

Indeed, our applied design can have a positive impact on our lives and cats lives, but we are still careful and we are aware of some potential drawback of our design. The current version of cat shelter can be altered to be more cat-welcomed. Besides, the materials we are using do not perfectly cope with the open environment. Although hard, wood may cause fire. This can be improved by choosing other materials that have the desirable properties. We are also considering multi-layers of materials, for example, inside cardboard (cats love them) and plastic and outside waterproofing paint. We now ensure the safety of electricity by separating them in a chamber, but recharging them takes effort. Are solar cells a possible solution? Our team is always thinking possible ways to improve our design.

Technical Details

Video: This is the last episode of our documentary series. We draw out, model and demonstrate our final design.

GBC Documentary P5

Thanks all for watching! The previous episode is about incorporating ‘Value Sensitive Design’ into the safety concerns of this hardware.


Having noticed it is the difficulty in capturing cats that largely impeded the executive of TNR (Trap, Neuter, Release), we realized that the feline-attracting characteristic of nepetalactone could be of great help (For more details on why nepetalactone appeals felines, see Project Background). Compared to cage traps and usual food lure, the pleasant scent of nepetalactone in catnip would appear to cats less of a pitfall, therefore more easily let down the guard of stray cats. With this need clearly identified, we devised a brand new product (hardware), which can attract and seize stray cats when needed, provides cats with comfortable and secure shelter, and contains an auto-feeder to reduce the workload of the volunteered caregivers. With a beautiful wish that this device would be the promised land for the roaming cats, we named it ‘Kitty Wonderland’.

Most of the features and their corresponding functions of the Kitty Wonderland are identified in Figures 1, which demonstrate the final version and the separate sections of our Kitty Wonderland. The functions and adaptations of every component will be discussed and explained comprehensively later in the Design.

Figure 1. The 3D Modeling Figure of the whole structure, The Base, The House and The Roof of Kitty Wonderland.

Before we came up with the idea of the design of this final version, we gathered and analyzed information and advice from specialists, officials and residence. Corresponding evaluations and modifications have been done to compare our hardware with the existing solutions and improve the possible performance of our design, as explained in the next section.

Evaluations and Improvements

Animal lovers in various communities have installed many simple shelters with food and water supplies under their apartments. The price of these simple shelters are cheap (Most of the shelters are made of paperboard plastics) and these shelters are tiny and light so it is very easy to transport and carry them. However, they are not waterproof and therefore could only be placed under the roof where only a confined space is available (Figure 2). Since these shelters only serve to provide stray cats with foods, no cat will be captured and therefore no sterilization could be done. In order to solve the stray cats problem thoroughly, capture and neuter are the priorities and certain number of cats needs to be sterilized to inhibit the surge of stray cats population before further measures are undertaken.

In addition, many rescue parties of cats and dogs have already adopted modified cages which serve purely to trap stray cats and dogs (Figure 2). However, this method presents issues and concerns due to the fact that those cages don’t actually offer any benefits to cats and dogs but trap anything enters the cage immediately. Therefore, cats and dogs are becoming increasingly indifferent to those steel cages, which not only fail to demonstrate their functions but also pose threats to the animal. Besides, the sharp and harsh appearance of those steel cages doesn’t appeal to cat and dog at all. Pedestrian and residence will also find those cages very abrupt and unattractive, thus having negative attitudes towards the actions of the rescue team. None of these is helpful in taking care of cats and dogs and rescuing them effectively, not to mention the aim of emphasizing the problem of stray cats and dogs to the public and encouraging every citizen to get involve in the rescue.

Figure 2. The investigation of the current solutions of stray cats problem.


Our Kitty Wonderland is made of wooden boards and some extra components like the camera and electric fan which enhance the functionality of the Kitty Wonderland. We select wooden boards instead of plastics or steels because wood is more nature and intimate to cat and it also has outstanding properties like relatively light and heat-insulated. Paintings, drawings and crafts could also be applied easily to the wooden boards to improve the appearance of our hardware. During the construction of the Kitty Wonderland, we simply nail all the components and wooden boards together.

The design of Kitty Wonderland is quiet complex, so the whole structure is broken down into three individual parts which are further explained. We name these three parts The Base, The House and The Roof respectively.

The pictures of The Base and The House are shown in Figure 3. The Base is consists of a wooden box with a lid, a 3D printed pedestal and a PVC tube of 90 cm long. In consideration of the protection and safety of battery and other appliance, we make the wooden box and cover the bottom of it with plastic, so the box is made waterproof and can protect the electric appliance inside the box. This wooden box could also provide a foundation and elevation for the main house which is placed on top of it, so our design could be placed on the streets where no shelter against rain is present and the House will not be submerged by heavy rain or flood. The plastic pedestal in nailed at the bottom of the Base and it is designed for the consolidation of the PVC tube, which runs all the way to the top of The House. The PVC pipe has two functions: To immobilized the house and to protect the wiring. Electrical appliance like the camera and the electric fan are installed on the top of the House. In order to connect the wires between the battery and the appliance without imposing potential danger on the cats and damaging the appearance of Kitty Wonderland, we apply this PVC tube into our design to allow wires go through it. Since the PVC tube runs through The Base and The House (The lid of The Base and the bottom of The House both have a hole with the diameter of the PVC tube in the middle), it connects and stabilizes the whole structure.

Figure 3. Demonstration of the appearance and design of The Base and The House of Kitty Wonderland

Right on top of The Base is The House. The House is the place where cats enjoy their lives. Two sliding electric doors are installed on the inner opposite sides of the House, and each door is controlled by a motor. After a cat enters the House, what happens is the sensor above the door detects the cat and the sensor sends signal to the central controller in The Roof or in The Base, which then activates the motors and closes the door. The door could also be adjusted to remain open, so the Kitty Wonderland becomes a habitat of cats and will not capture the cats if necessary. An inverted camera is also installed at one top corner of The House to monitor the conditions inside the House for recording and safety purposes (For more detailed safety considerations, see Application and Safety below). The chemical of our final production, the nepetalactol, and the foods inside the auto-feeder are used to further attract and entertain the cats. The nepetalactol is placed inside the essence oil container which is situated on the top of The House. The wooden board of the top is processed so that a total of 49 ventilation holes with diameter of 2 cm are created. These holes allow gas exchange to occur, and they also allow the wires from the motors and sensors inside The House to reach The Roof safely and easily. Through the ventilation holes, the fragrance of nepetalactol could easily diffuse down into The House where its enthusiastic consumers live and play. The foods and water inside the House also allow cats to stay for a long period of time. All together, these treats will make our design a paradise for cats.

The final section of our design is The Roof, as shown with the whole structure in Figure 4. In the 3D Modeling Figure, the demonstration on the left is the bottom view of The Roof. An inverted electric fan is fixed on the roof. Its function is to strengthen the air flow though our design and facilitate the diffusion of nepetalactol inside the essence oil container, so distant stray cats are also guided by the fragrance of the oil to our Kitty Wonderland. Since there are electric wires and appliance under the Roof, the lateral sides of the Roof are sealed in consideration of the safety of cats as well as the appearance of the design. Thirteen ventilation pores are made on two sealed sides to allow air flow through our design. The Roof is fixed on the top of The House by bolts and nuts, which allow us to remove The Roof and add nepetalactol quiet easily.

Figure 4. 3D Modeling Figure of The roof (Picture 1) and the demonstration of the detailed design of The Roof. The final structure of our Hardware in shown in picture 4

All sections are combined to produce the complete structure of our hardware. In practise, the Base Lid will be placed on top of The Base under The House to provide an extra shielding for the electric appliance (Figure 4).

After recognizing the functions of each component of our design, a brief description of the scenario of implementing our Kitty Wonderland is written below for your further understanding.

Kitty Wonderland

This video is a brief demonstration of the function of the newest version of our Kitty Wonderland. Updated on Dec/6 2018. The recording firstly introduces the structure inside the ‘Kitty Wonderland’ from the roof to the house. This introduction includes almost all parts involving the electric fan, essence oil container, automatic feeder, door motor, door hinge, the door, sonar detector and the wiring. Then, the video demonstrates how the sonar detector senses the object and closes the door. Afterwards, the wiring on the attic is shown and the remote camera is introduced. In this example, the controller of the ‘Kitty Wonderland’ identifies the object as ‘not a cat’ and opens the door remotely.

Application and Safety

Our design will be placed on flat ground. Direct exposure to intense sunshine or heavy rain should be avoided as much as possible in consideration of the conditions of battery and other electrical appliance in the Base, in spite of the heat insulation and waterproof properties of the Base. The electric fan under the roof will spread the fragrance of the essence oil, which would fascinate the cats and guide them to our design. Foods and water will be placed inside the House in advance to treat and ease the cats. After a cat enters the House, the motion of the cat will be detected immediately by the sensor which then sends a signal to the electric door through the controller. If necessary, the electric door will shut down so that the cat is remained in our design and awaits the arrival of professionals. The whole process will be recorded by the camera inside the house for future reference and safety consideration. If there is an emergency, the workers nearby will be acknowledged through the camera immediately and they could then remotely control the electric door and release the cats.

Apart from the camera, the electric fan and the nepetalactol under the roof is completely isolated from the range of activity of the cats. Two sealed sides of The Roof mainly serve to keep the cats away from these potential danger, even though the fan is working at very low power and the wires are sealed. The wiring inside the House, as well as the gears and racks of the electric door, are also covered with tapes and metal shielding to prevent cat from touching these components. The tapes and metal shielding are removed in the pictures and 3D Modeling Figures above for explicit demonstration of our design. The position of the design should also be away from places with crowds and harsh weather. Long-term heating by sunlight might result in battery failure, so we place the battery under the structure and insulate it by using another wooden box. Our recommended position of the design is place where vegetation and shades are available, like a park or sides of a trail, and definitely where cats are playing.

In the future, we are going to make extra refinement and improvement on our design(Kitty Wonderland). These include adding telecommunication system to Kitty Wonderland and developing our own cat-searching application(App) which allows our Kitty Wonderland to be more practical and versatile and allows the public to become more engaged with our design and in solving the feral cat issue.