Dec 062013
 

This is a prototype for a project with an Austrian partner, with a rotary switch mounted inside a pi3g case. We are able to provide custom machining on our custom cases, and assembly services. Please contact us if you are interested.

rotary-switch-closed

Case closed, rotary switch is mounted. The opening had to be enlarged for a good fit of the switch. A plastic ridge on the top of the switch base was in the way.

rotary-switch-inside

A view from the inside – the switch is mounted with glue in this prototype.

rotary-switch-opened

The opened case from above. This is a stock Raspberry Pi Mod B 512 MB.

Rotary switch

The rotary switch is order number 1123676 from Farnell (Lorlin, PT6509/BMH rotary switch with three poles and positions). It will fit in exactly one position into the TEKO/pi3g Raspberry Pi case, which is shown above.

As already stated, the opening had to be extended to allow space for the plastic ridge. It is about 2 / 3 of the thickness of the case at this point, making a machining in steps (accomodating the ridge inside the case, hidden from view) impracticable. This is, because the case would be too thin at this point for attaching the switch with a nut.

Thermic implications

We tested with “stress” (stress –cpu 5 –io 5 –vm 5 –vm-bytes 10M –timeout 360000s).

temperature-rot-switch

As you can see, the temperature inside the case stays below 45 ° C at 20 ° C ambient temperature, even under high load. Thus, the rotary switch does not adversely impact the Raspberry Pi’s performance. (Processor auto-regulation by the Raspberry Pi begins at 60 ° C AFAIK).

Further research

We recommend further research on Mouser, RS and Digikey to look for a better-fitting option, whích will require less space in the case and less machining / finishing. For a hobby project this rotary switch might be a good option, though.

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