Twistie

What it does

Twistie is a compact, power-free tool that lets users open bottle caps with one hand—no strength or complex motion needed. It offers practical help for anyone with limited hand use.

Your inspiration

While watching a documentary on rural food-making, I was deeply moved by a mother and daughter who each lost their right arm in separate accidents. With no access to prosthetics, they lived their lives using only one hand. Similar stories are common in rural or industrial areas, yet most tools are still built for two-handed use, excluding those who don’t fit the norm. Instead of high-tech solutions like robotic arms, I aimed to create a simple, affordable product that restores independence. This project began with the belief that inclusive design should be a standard, not a special feature.

How it works

Twistie is a power-free assistive cap opener designed to make it easy to open bottled water caps with one hand. Inside the product, diagonal rib structures create strong friction and secure grip, allowing it to adapt to various cap sizes. Its usage is simple — the “Push and Twist” method. [Push] Press Twistie vertically onto the bottle cap to lock it in place using the internal structure. [and Twist] With just a slight motion of the thumb, the cap can be easily turned and opened. Once the cap is loosened, it can be repeatedly opened and closed with one hand, making it convenient for everyday use. Twistie operates solely on the user's hand strength, without the need for electricity or complex mechanisms — offering a reliable and practical solution. Simple in structure, powerful in impact. With Twistie, just Push and Twist.

Design process

One-handed users, as well as people temporarily limited to using only one hand—such as parents holding a baby, individuals recovering from injury, or drivers on the go—often face unexpected challenges in their daily routines, one of which is something as basic as opening a water bottle. Standard bottle caps are designed with two-handed operation in mind, making them inaccessible in these situations. To solve this, we developed a thumb-operated assistive device that firmly grips bottle caps and allows them to be opened with minimal effort, requiring no extra strength or support from the other hand. Our development process involved creating multiple iterations of the thumb-pushing mechanism, using 3D printing and Pinkisol for quick prototyping. We tested each version with different hand angles and grip conditions to ensure intuitive use, even with wet or shaky hands. The final design includes anti-slip protrusions around the outer edge for secure thumb contact and an internal diagonal widening structure that adapts to various cap sizes, ensuring consistent performance across different bottle types.

How it is different

Conventional bottle openers are two-handed, requiring the bottle to be held in one hand and the cap to be turned with the other, making them difficult or impossible to use for users with only one hand. Twistie, on the other hand, has completely redesigned its operation so that the cap can be opened by simply holding the bottle with one hand and pushing with the thumb, rather than simply assisting the force. This is highly original in that it solves the structural limitations of the existing product by ‘innovating the way it works’. In addition, the small, lightweight size that fits in one hand makes it highly portable, and it aims for ‘universal design’ that considers not only people with one hand disabilities but also people who can only use one hand temporarily.

Future plans

We are refining the mechanism to ensure smooth operation with minimal effort, especially for twisting and gripping. The product is being developed to be compact and lightweight, making it easy to carry and use on the go. Our goal is to see it sold in everyday locations—convenience stores, supermarkets, train stations, and hospitals—wherever beverages are available. To ensure accessibility and affordability, we’re optimizing the structure for mass production via 3D printing and injection molding. This will allow the product to reach not only consumers but also relief agencies, welfare programs, and underserved communities.

Awards