Technology that translates your writing and doodles into computer-generated imagery has been around for a while, but it generally requires special material to write on as well as a smart writing implement, and it doesn't run cheap. But if you happen to have a chalkboard, some pulleys, and a few ultrasonic sensors lying around, you can make one yourself.
Guide dogs are great, but vision-impaired people sometimes need to find their own way through complex environments. Instead of checking for obstacles with a trademark white stick, inventor Steve Hoefer has another idea: Use wrist-mounted sonar. Hoefer designed a haptic gauntlet with ultrasonic sensors mounted just over the knuckles. The Tacit, as it's called, is encased in a neoprene cuff and can sense objects from about two and a half centimetres all the way up to 3 metres.
