This pictorial presents a novel method to render color patterns using electrolysis applied onto open wet surfaces. By implementing electrodes within a wet object and electrifying them, electrolysis can occur and generate ions. We designed a color-forming display using color indicators reacting with such ions. This method can display patterns according to the shape of the electrode. By reversing the polarity of the electrodes and generating reversed-polarity ions, it is possible to fade the existing pattern and display a contrasting color. The proposed method does not require moving parts; thus, it is low cost and easy to compact. Also, some foods containing pH-reactive substances can be used as a display medium. Therefore, the proposed method can realize an information display using various objects common in everyday life, such as decor or food.

Due to its natural warmth, wood is frequently used to produce touchable objects such as furniture and signboards. Laser cutting machines are becoming common in personal wood processing to cut and engrave wood. In this paper, we propose a method and workflow for producing various sensors and electrical circuits for interactive devices by partially carbonizing the wood surface with a laser cutting machine. Similar to wiring on a conventional printed circuit board (PCB), the carbonized part functions as a conductive electrical path. A method for creating electronic circuits and sensors made of carbon graphene on botanical materials has been proposed. This technique makes use of a raster-scanning femtosecond (fs) laser, which is less common for personal fabrication than a constant-wave (CW) laser. Moreover, raster-scanning requires a substantial amount of time to create a circuit that is mainly made of conductive lines. This paper extends the method with a defocused vector-scanning CW laser beam and reduces the time and cost required for fabrication. The proposed method uses an affordable CW laser cutter to fabricate an electrical circuit, including touch sensors, damage sensors, and load sensors on wood boards. The circuit can be easily connected to traditional PCBs and electric parts such as one-board microcomputers using metal screws and nails typically used in DIY woodworking. We develop ease of use software design tool that supports the creation and fabrication of carbon paths. In addition, we report on a series of investigations, including optimizing wood materials and laser parameters to establish design guidelines.

Research was conducted on a digital information display using electrolysis bubbles. Although the research mainly focused on information displays in daily life, the ephemerality of bubbles is also a promising method for dynamic art installations. In this paper, we present two novel artworks using this electrolysis bubble display mechanism. First, we present “UTAKATA,” a ticker-like bubble display, using a running-water channel. Seven electrodes are placed linearly on the channel bed, and they generate text messages using bubble dots that drift toward the lower end of the channel. Second, we present the “Bubble Mirror,” which is a water pan with a camera that captures a visitor’s face and displays it using electrolysis bubbles as pixels. Facial images with six levels of grayscales are displayed on the water surface using 32 × 32 electrodes. We evaluated the output properties of these configurations and discuss the results obtained.

We propose a method for controlling a device that draws letters and illustrations on large, flat surfaces. Similarly to conventional inkjet printers, the device ejects a volume of water from its nozzle, with the water droplets then forming dots on surfaces such as soil, concrete, and sand. Both the direction of the nozzle and the water pressure can be controlled to enable the device to draw arbitrary two-dimensional patterns within a semicircular region with a radius of six meters. The device can draw letters and illustrations. We have investigated the pressure, the shape of the nozzle, and droplet size in order to avoid further division of the droplets into even smaller droplets while traversing the air. In this paper, we introduce the mechanism of this device and demonstrate how a user can take advantage of this new drawing tool.

Research was conducted regarding a display that presents digital information using bubbles. Conventional bubble displays require moving parts, because it is common to use air taken from outside of the water to represent pixels. However, it is difficult to increase the number of pixels at a low cost. We propose a liquid-surface display using pixels of bubble clusters generated from electrolysis, and present the cup-type device BubBowl, which generates a 10×10 pixel dot matrix pattern on the surface of a beverage. Our technique requires neither a gas supply from the outside nor moving parts. Using the proposed electrolysis method, a higher-resolution display can easily be realized using a PCB with a higher density of matrix electrodes.Moreover, the method is simple and practical, and can be utilized in daily life, such as for presenting information using bubbles on the surface of coffee in a cup.