Novena Heriloom switches

Novena Heirloom – switches

The original notion for switching the Novena Heirloom was to use touch switches below the rear panel with graphics engraved above to indicate their location plus an LED to indicate the switching action.

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I briefly tested the idea with an AT42QT1010 breakout board and found it to work pretty well. But when Bunnie put together a PCB design based upon my intended configuration, it proved to be unreliable.

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So that idea was shoved onto the back burner for consideration at a later time. I would need a substititute in the form of a mechanical switch.

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When the time came to begin resolving the issue, I retrieved a Snaptron sample box I had acquired prior to the Novena project. This seemed like the right application for these simple, mechanical dome switches.

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They only require a split pad on the PCB and a small vent hole to vent the switch area under the tape used to position it above the contacts on the board.

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The available depth to accomplish implementation of a mechanical switch would be the thickness of the rear panel composite. The PCB would be mounted flush to the bottom and the space above the rear panel would be occupied by the LCD panel in the closed position.

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The Snaptron switch domes would occupy maybe a third of this available depth, so a switch actuator would have to reside within the remaining dimension.

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The hinges on the Heirloom have a dark bronze chemical finish. I had been thinking about other elements in the design that might pick up on this color and decided to try something in brass that could be finished to a similar color.

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I like switches that use a recessed area for an actuator. They are common in space constrained situations and environments where accidental switching would be undesirable.

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It occurred to me that I might create a sculpted look for the switch base component by cutting the recesses on the CNC mill using a slightly open spacing between horizontal tool passes.

After these were finished, I made the brass actuators on the lathe. The push button tip projects just to flush with the rear panel surface. The actuators have a projecting pin on the bottom that pushes down on the dome switch to give it just the right audible and tactile feel. They then received a chemical darkening finish followed by a coat of a clear nylonic finish.

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