Sunlight, illuminating light, mechanical vibrations, thermal vibrations, even plant and animal fluids, all have energy that can be transformed into just that. Energy is usually too weak to be of use to humans. But advances in basic technology and manufacturing processes have changed the prospects for the application of this free energy.

Recently, scientists at Ritsumeikan University in Japan have developed a device that can sense the consumption of diapers by using urine as an electrolyte solution. level of “urine power”, and a matching urine volume sensor. The study provides a solution to a patient care problem.

Urine power source has promise to solve patient care challenges

Scientists working on urine-generating technology are obviously not working with mud. This technology has a clear application in patient care and has already progressed to the product testing stage.

Babies and people with lower limb paralysis wear diapers constantly, and caregivers have to regularly check to see if the diapers should be changed, which creates a certain amount of caregiver stress and psychological burden.

If a sensor that can feel urination is embedded in diapers, caregivers can be notified in time to change the diapers, making it extremely convenient for both doctors and patients.

This is not a high-tech idea, as there have been a variety of products in this field before. However, no matter what sensor circuit design is used, the issue of power needs to be addressed, and obviously sensors cannot work without a power source.

Conventional sensors require a lot of drive voltage to work, and designers had to use dry or coin cell batteries to power them, which is contrary to what diapers were designed to do.

From the wearer’s point of view, the new product should not add additional burden or discomfort. From the caregiver’s point of view, it is desirable that the product be as simple and easy to use as possible, especially if there is no need to install or replace batteries. One type of tedious operation. In addition, the cost of the entire circuit must be low enough to meet the requirements of a one-time use.

In this way, there should be no conventional drive power supply in the circuit. So, who will play the role of the power supply? Researchers thought of the urine itself.

How the urine power source works

The presence of various ions in urine, which counts as an electrolyte solution, offers the possibility of using urine to generate electricity.

The researchers arranged sheets of activated carbon cathodes and aluminum foil anodes inside the urine, which together with the urine form the battery. Then there was the problem of solving the sensors and circuitry.

Since urine batteries produce energy at the micro-watt level, the researchers needed subtle contrivances to harness such a small amount of energy to drive the sensors. Eventually, they came up with the idea of using tiny capacitors to store weak electricity. When the accumulated energy is large enough, the capacitor automatically discharges, releasing a pulse signal via radio to the outside world.

The energy is then zeroed out and the capacitor waits for the next discharge process.

When the volume of urine is large, the urine cell provides a more stable charging voltage for the capacitor, which will continue to gain energy and thus continue to discharge to the outside world. Release pulses. Depending on how often the pulses are released, an external signal receiving system corresponds them to the volume of urine, and we know the real-time volume of urine absorbed by the diaper. .

Printed electronics make it possible to incorporate these components into diapers at a very low cost and the price of the final product can be brought into the reasonable range.

In addition to urine, plant fluids can also be used to generate electricity.

The researchers also experimented with a variety of environmental power generation techniques, including plant fluid battery technology, which is a lot more difficult than urine batteries.

This is because plant fluids, although also electrolyte solutions, are more dispersive and lower relative to the amount of liquid somewhere compared to urine. The aforementioned urine power source provides microwatt levels of energy, while plant fluids can provide only one percent of that. This makes it more difficult to drive external wireless sensing circuits.

However, the research team has now succeeded in creating ultra-low-power wireless sensor circuits that, when coupled with plant fluid batteries, can measure changes in the amount of body fluid in the plant.

This is significant for agricultural automation. In future agricultural production, using bodily fluid sensors placed on certain plants, it will be possible to estimate the irrigation needs of farmland in real-time, enabling Smart Production.