The Cthulhu Shield is the worlds first open source sensory substitution and sensory augmentation development platform! Sensory substitution is the name that has been given to tools and techniques that take sensory information you would normally receive on one sensory organ, and presents that information in another form to another sensory organ. Your brain then figures out what to do with this information and translates it into usable data. The Cthulhu Shield lets anyone experiment and make devices that can expand your sensory experience! This input device attaches directly into a 5V Arduino development board, enabling it to electrically activate nerve endings in your tongue (yup, your tongue) through an array of 18 electrodes with the included Flexible Electrode Array.
This type of "tongue I/O" could be extremely useful to replace senses that are weakened or absent, and could even be employed for augmentation, such as sensing infrared or ultrasonic signals for example, or receiving updates from the Internet. Using an 18 electrode grid to tactilely display signals on the tongue, the electrodes on the array can be activated with patterns of electrical pulses to depolarize nerve membranes in the tongue to create different types of touch sensations. You can use these touch sensations to draw shapes or simple images on the tongue, feel different sound frequencies, receive turn by turn directions with your tongue, send keystrokes to your computer, control the cursor, or even control a mobility device. Additionally, the Cthulhu Shield can sense whether or not your tongue is in contact with different electrodes using capacitive sensing.
You can attach other SparkFun sensors to your Arduino, like a small pressure sensor to use the Cthulhu to feel the force you are exerting on an object if you have nerve damage in your hands or are wearing thick gloves. Many people have used tongue stimulation to improve their sense of balance as well by using pressure sensors or accelerometers.