A Japanese company unveils a device that will let you know ahead of time when you will need to go to the toilet. Japanese company Triple W Japan has invented Dfree, a device that fits on your underwear and tracks your bowel movements. The company says the device will come in handy for people who suffer from faecal incontinence, or those that just need more time to find or go to the bathroom. The device, unveiled last week at the Combined Exhibition of Advanced Technologies (CEATEC) on the outskirts of Tokyo, is not yet on sale but could be on the market by spring next year. "This device predicts faecal excretion. The device goes on your stomach and uses ultrasonic waves to monitor your internal organs and sends the data to smartphones to be displayed," said Ryohei Ochiai, of Triple W Japan's Solution Development. However, the company is still working on alternative methods to secure the device to underwear, because many people are concerned that it may chafe their skin. "We are still in the process of looking at whether to use tape or belts to secure the device to the stomach. However, many elderly people are concerned about skin chafing. So we are looking at how to secure the device safely and solidly," Ochiai said. Japan's growing elderly population has spawned a large industry to cater to them. By 2060 two out of every five people in Japan will be aged 65 or older, with the population falling by 30 percent to below 90 million - the fastest aging population among developed countries. Many Japanese visitors to the booth said they saw the advantages of the device. "I think this device would be great for (elderly) people who are not ready to use diapers but need them," said 43-year old Naoki Wadamori, a teacher and resident of Tokyo. Although not the primary target, the device will also work on babies, the company says. While the firm must also work out how to secure the device on a toddler, it believes the device will be useful for babies and help parents with toilet training.