Doppel is a new breed of wearable device, one that its developers say can actually change the wearer's mood by delivering a tactile beat to their wrist. The makers of 'doppel' call it the next generation of wearable technology - one that can actually change the mood of the user. They say the device taps in to the body's natural rhythm and gives the wearer control over how alert or relaxed they are. Similar to the way that upbeat music can motivate the body, while downbeat music relaxes; doppel provides a tactile beat to the wearer's wrist that they can adjust to make themselves feel more alert or relaxed. "Doppel, as it stands, delivers two separate rhythms -- one high and one low. The high rhythm essentially delivers a rhythm which is higher than your resting heartbeat, and the lower one which is lower. And it works in a very similar way as to when you listen to upbeat or downbeat music. So, in the same way that upbeat music can excite you or bring you up, make you more alert; doppel does this. And it does the same thing with the downbeat tempo which you feel calming you down and even helping you into sleep," said Andreas Bilicki, co-creator of doppel. Bilicki is part of a team of scientists, engineers and designers who met on a joint course run by Imperial College London and the Royal College of Art. Their research into psycho-physiology - the way a person's mind and body affect one-another - inspired them to design a new technology that could harness the body's innate response to rhythm. Together they formed Team Turquoise to make their hypothesis a reality. Co-creator Nell Bennett explained how doppel represents truly empathic wearable technology, instead of the current crop that often just monitor the body's activity. "Wearables currently are mostly centred around monitoring and providing stats and statistics on how you perform in your everyday life. And we feel that technology, and certainly wearables, need to a step beyond that to become something that becomes truly integrated seamlessly into people's lives. So we wanted to make a wearable that was about changing how you feel; not just giving you nagging stats and statistics on how many steps you may or may not have walked that day," Bennett said. Doppel is synchronised to each individual via a smartphone app that measures their resting heart rate. This is all the information needed for the device to tap into the body's natural response to external rhythms. "You take your resting heart rate through your phone, and then that's the bio-data we need to set the levels that you need to either (get) calm or to get going. It's not a lot of data, but we're using it very smartly, and that's the approach we take," said co-developer Jack Hooper. To control the level of doppel's pulse, the wearer simply presses the face to make the beat faster or strokes the bezel (grooved ring holding a watch face cover) to slow the pace. It's similar in size and shape to a wristwatch, but with the active mechanics positioned on the sensitive inside part of the wrist. This was crucial for the device to work effectively, said Hooper. "We wear it on the inside of the wrist rather than the outside of the wrist. Because this is a psychological mechanism, having doppel's pulse wear you expect feel your own pulse amplifies the effect," he said. Bennett conceded that convincing people to wear doppel on one of their wrists -- instead of, say, a watch or a fitness tracker -- was something they had to consider. "Although 'wrist real-estate' is very expensive these days, it is actually the most suitable place to have it because if you think 'I need to tune down a little bit and relax', you're not going to start stroking your ankle or pressing buttons behind your head. So, it also needed to be somewhere that was very easily assessable," she said. Team Turquoise says prototype models have been successfully tested on hundreds of people. They say doppel was also independently tested by psychologists at Royal Holloway University of London; with their controlled tests showing the device can improve alertness when correctly set to the user's preference. The team is planning further independent tests aimed at validating doppel's ability to calm people down and reduce anxiety. They recently launched a Kickstarter campaign to turn their prototypes in to consumer-ready models, with backers to be the first to get their hands on their own doppel. Bilicki, along with the rest of Team Turquoise, believe doppel is a unique and game-changing addition to the burgeoning wearable technology market. "As far as we are aware, no one else has developed this type of technology -- it's a new breed of wearable that actually allows you to change the way you feel in a natural and simple way. And to that end, we've geared all our technology to deliver the best experience possible."