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What's a tessellated circuit??
A new, efficient, versatile and reusable way to create circuits, that's what.
“Tessellation: the tiling of a plane using one or more geometric shapes.” That describes how these little circuit boards fit together. They are designed as functional blocks which can be mounted side-by-side then wired together to create larger systems in a quick, efficient and low cost way. The geometric shapes used are nothing complicated—just squares and rectangles—but their edges share some common dimensions. In a very international way these dimensions employ both inch and metric bases. The inch basis comes about because most of the world's perfboard is based on DIP package dimensions and uses 0.1" space between holes. The unit board size is based on 10 of these tenths, one inch or 25.4 mm. However, the basic board size is 25.0 mm by 25.0 mm. The remaining 0.4 mm is reserved as a bit of wiggle room so that imperfectly made boards will still tile.
Boards are not limited to this unit dimension. An N by M unit board simply needs to be (N-1)×25.4+25.0 mm by (M-1)×25.4+25.0 mm. Or, put another way (N×25.4)-0.4 mm by (M×25.4)-0.4 mm. So a 2 unit board is 25.0 mm by 50.4 mm.
Figure 1. The dimensions of the unit board. The holes are 0.086" (a #44 bit), though larger sizes close to this can be used instead.
Mechanically, an innovation is the use of incomplete mounting holes. The system is such that a unit board has exactly the equivalent of one mounting hole, but that hole is divided into four parts, a quarter hole at each corner! See Figure 1. A major advantage of this mounting method is that almost no area is wasted within the board so that the area available for circuitry is maximized. The size of the defined (partial) holes, in conjunction with the reccommended mounting hardware sizes, either inch or metric, means that most often the boards can be “press fit” between upward-pointing machine screws and that they will lock in without needing nuts to hold them. Nuts to hold the boards down are always an option.
Any sides longer than one unit need to have “half holes” at the appropriate locations, see Figure 2, below. (I've been using 1/8" diameter for these, so they do not increase the insertion force needed to place a board.)
I'm calling these tiles, these single-function boards, “Li'lBoards.” Click for an introduction and listing.
Figure 2. An assortment of designs. A mix of 1×1, 2×1 and 2×2 units.
- There are many many designs (see the intoduction page);
- Their outline and form factor is Open Source. Layout files for Eagle, kicad and PCB in the works;
- They can be wired together in many ways;
- They can be mounted in many ways;
- Several designs have custom online support calculators designed to speed your work.