A new attractive electronic keyboard system
Ihave developped in the recent years a concept of electronic keyboard control by fixed metallic pads operating by epidermic capacitive effect. This system is reliable, efficient, inexpensive, and wearproof. A small metallic pad (minimum size of 6 to 7mm), is sufficient for an isolated key, and can be formed to match the particular use (rounded, flat, or hollow).
The preferential domains of use concern all the keyboard-operated machines, in particular the personnal computers, and chieffly the small portable instruments, telephone terminals, pocket computers, ..etc. The only practical limitation of use comes from the requirement of bare skin contact, precluding gloves on for example.
At the beginning the device included for each key an electronic circuit of analog type, rather complex. In 1992 I discovered new means of integrating nearly all the electronic functions into programmable commercial digital circuits, such as EPLD or FPGA. In 1992-1995 I succeeded in simplifying and extending this integration to all the pertinent combinated control function kinds. The elementary operation results in a simple, bounce-free, fast voltage signal, enabling faultless cascaded flip-flops, for example. In addition, the EPLD gives the opportunity of enforcing all sorts of mutual conditions beetween different keys, such as inhibition, association, priority, etc. In this line of idea, the possibility of precluding any faulty double action of neighbouring keys enables one to bring keys closer in small or very small keyboards.
An efficient operation requires only a light touch, including just the minimum physiological contact sensation. No additionnal combined sound signal is necessary to ensure blind successfull operation. Obviously use of large size EPLD's enables integrating some (or all) intrinsic functions of the application, in addition to the keyboard operation. To-day bigger and bigger such circuits become commercially available. Electrostatic hazards can be easily coped with by different means adapted to the particular uses. The EMC (electromagnetic compatibility) is ensured by the limited frequency range of the signals driving the keys.
The present keyboard concepts have been implemented in various electronic experimental devices for over 10 years, and proved perfectly efficient and reliable.
I would readily offer the knowledge associated with EPLD integration, (and also all know-how concerning the most usefull types of adapted keys), to any willing industry manager, at little exacting conditions.