Scientists have transformed a simple children’s toy called a “drinking bird.” a tool capable of generating useful amounts of electricity.
This generator could be used in the future to power a variety of small indoor and outdoor electronic devices.
How does the unchanged “drinking bird” work?
The drinking bird’s body is vacuum sealed and consists of two glass domes connected by a tube, one forming the head and the other the tail. The head dome has a protruding beak and is covered with an absorbent cloth, while the tail dome is free.
The body is mounted on a series of plastic legs that act as a rocker and is filled with a volatile chemical compound called methylene chloride. Some of this chemical is in the liquid state and some is in the gaseous state. A glass of water is placed in front of the toy at a height so that the bird’s beak can be immersed in the liquid.
The user first presses their head into the cup so that the fabric cover can absorb water through the spout. Once the head is released, the body returns to vertical orientation thanks to the weight of liquid methylene chloride in the tail.
When water evaporates from the fabric, a cooling effect is created in the head dome. This causes the methylene chloride vapor in the head to condense into liquid, which then moves down to the tail. Because the pressure in the lower part of the body is now greater than in the head, the methylene chloride fluid is forced up through the tube and back toward the head.
This shifts the toy’s center of gravity forward, causing its body to bend forward and dip its beak into the glass to drink more water. At the same time, a free passage opens between the head and lower body, which equalizes the pressure. The liquid methylene chloride then sinks back down, allowing the process to begin again… and repeat itself again and again.
The new electricity-generating “drinking bird”
A team of scientists took one of these toys and attached two disc-shaped triboelectric nanoelectric generator modules to each side. These devices take advantage of the triboelectric effect, where certain materials become electrically charged when rubbed together, which is responsible for the static charge created when you comb your hair.
Therefore, the entire assembly is known as the Drinking Bird Triboelectric Hydrovoltaic Generator or DB-THG by its English acronym.
In laboratory tests conducted at an ambient temperature of 24ºC and a relative humidity of 20% ± 5%, was able to run for 50 hours on just 100ml of water. In addition, an output voltage of up to 100 volts was achieved, Enough to power devices such as calculators, temperature sensors and 20 connected LCD screens.
Scientists are developing a successor that should offer significantly better performance than the existing modified toy.
Drinker Bird’s triboelectric hydrovoltaic generator offers a unique way to power small electronic devices in ambient conditions while using water as a readily available fuel source. I’m still surprised and excited to see the actual results.
An article about the research was recently published in the journal Device. In the video below you can see the DB-THG in action powering LCDs.