Poor man's flexible input device: keyboard sketched on paper and a touchscreen

Here part of the code with input/output example:

// touchKeyPadCalc2.js
// (c)20181004_aO
var kvs = "789CA456*/123+-00.==" // key values grid linear
  , tkp = new (require("TouchKeyPad"))(
     0,141,24,103,5,4,kvs) // grid area, cols, rows
  , trd = new (require("TouchRD"))(B1,A5,A6,A7
    ,function(x,y,t) { if (!t.t) // on un-touch:
      console.log(t.x,t.y,tkp.key(t.x,t.y),tkp.k,tkp.r,tkp.c); }
    ,require("TSRD26_142x104_cfg")
    );

The actual calculator is still on the list (suggestions are welcome) as well as attaching any kind of display. Output of input shows in console so far (: - Touching 8 2 . 5 x 3 = produces this output (formatted and 'headed' posthume for legibility):

`
touched lup lin -grid-
@       key key row col
  x   y val idx idx idx
--- --- --- --- --- ---
 38  36  8    1   0   1
 39  76  2   11   2   1
 64 100  .   17   3   2
 40  58  5    6   1   1
 96  57  *    8   1   3
 69  75  3   12   2   2
108  96  =   18   3   3
`

PS: Configured screen resolution is 142 W x 104 H spots (pixels), 0/0 is at left (x) top (y). Reasons for chosen resolution will be subject of another conversation.

...more to come...