Kaliko Systems Limited

Make a Low-Power Media Server

Case Materials

For home use the main requirement of a case material is that it has the strength and rigidity for both safety and the forces associated with using plugs and sockets. The case materials in order of complexity that I considered were:
  1. Re-using a simple cardboard box or plastic food box. These boxes lack the rigidity for electrical safety and the forces associated with plugs and sockets, and can often look dreadful.
  2. Electronics plastic box (typically made of ABS, Polystyrene or Polycarbonate).The box safety is good and the bottom (not the lid) has adequate structural rigidity for sockets. As a low cost case, they usually look good in the background.
  3. Wooden box. Wood is a good insulator and certainly rigid enough, but it takes a surprising amount of skill and time to make a good-looking wooden box. However, for many people a beautifully made wooden box is unbeatable.
  4. Aluminium box (typically folded or die-cast aluminium). Even thin aluminium is rigid enough, but the boxes are relatively expensive. To look acceptable it needs to be wire brushed or painted.
  5. DIN-rail mounting module box. These standardised industrial boxes are used for relay boards, but provide terminal blocks not sockets, and look too industrial for a home setting.
  6. Steel box. Very strong, but it is difficult at home to cut rectangular socket holes in steel, other than by filing. It must be either stainless steel or painted to prevent corrosion and look acceptable.
I decided that an electronics plastic box was the best compromise. ABS boxes are the most readily available in different formats and sizes, and are low cost. Also, as they are usually black they fit in with the color scheme of most home equipment and likely case plugs and sockets. Black has the additional advantage of making labelling easier and hiding any minor machining blemishes. The ABS boxes I chose included rubber bungs that hide the case screws, so with a snap-in case plugs and sockets this gives no exposed metal that requires earthing. The drawback with ABS and other common thermo-plastics is that they have a low melting point that makes it tricky to cut cleanly with power tools (see Machining ABS).


Once the case is machined then the mounting, wiring and labelling of the relay board and case will complete the case.

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