Hackaday Prize Entry: Tongue Vision


Visually impaired people know something the rest of us often overlooks: we actually don’t see with our eyes, but with our brains. For his Hackaday Prize entry, [Ray Lynch] is building a tongue vision system, that will help blind people to see through one of the human brain’s auxiliary ports: the taste buds.

tongue-vision-thumb
A display for the tongue (tongue image by Mahdiabbasinv).

The concept of tongue vision has already been proven. Brainport, a tongue vision system invented by Paul Bach-y-Rita is already available to patients. However, what’s missing is a low-cost open-source hardware alternative that makes the technology available to patients who can’t afford the $10,000 product. [Ray] set out to start this project. The design for his first prototype looks promising already, and all sources will be released as open-source once he can prove that his concept works.

Basically, the system consists of a digital camera that sends image data to a lollipop-like electrode matrix which stimulates a region on the patient’s tongue. In a training phase, the patient learns to interpret the stimulation pattern as the original camera image. For the electrode matrix, [Ray] designed a double-sided PCB with a 16×16 grid of taste-bud-stimulating pixels. Each of this pixels features an exposed via, which acts as the anode, and an exposed ring-shaped pad around the via, which acts as the cathode. The 16 columns of anodes are driven by two MC14555P high-side multiplexer, while the 16 rows of cathode-rings are driven by 74LS156D open-collector multiplexers. Think of it as a LED matrix without the LEDs. The image could be delivered by a Raspberry Pi with attached camera – or by the patient’s smartphone.

tongue-vision-row-column-intersection

If only a few assumptions about a tongue’s actual resistivity and sensitivity prove true, the assembly could indeed produce the desired sensation on a tongue once the first batch of prototype PCBs arrives. Either way, [Ray’s] PCB layout — which is also his first contact with EAGLE — is eye candy, literally. Our tongues are looking forwards to see the prototypes in action!



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