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Revision F Prototype updates

Dear Reader –

Here are some more updates about the Revision F (6th generation) prototype designs.  These are the designs we’ll be pushing through the various regulatory processes that will allow us to manufacture and ship the Mooshimeter.

SD Card and Reset Button Access

On previous versions of the meter, the SD card has been tucked in underneath the batteries with a hinge-type connector.  To remove the SD card required disassembling the enclosure, removing the batteries, then popping out the SD card.  Obviously it would be much nicer to have the SD card more readily accessible, but the constraints of injection molding make cutting slots in solid parts a very expensive proposition.

The most economical way of making the SD card accessible was to create a slot at the meeting of the two enclosure halves.  This required moving the parting line between the two enclosure halves, which meant distorting the shape of both halves and removing material at the slot on both sides.

Since there’s now a slot in the side, it seemed like a good idea to make the “reset” button accessible through a pin-hole as well.  That’s the small hole you see next to the SD card.

New Electrical Features

In keeping with our stretch goals, the resistance measurement subsystem has been overhauled and now includes a more accurate current source with two current settings, one in the tens of nanoamps and one in the microamps.  The spec sheets will be updated soon.

The new enclosures are being printed and the new circuitboards are being fabricated.

More to come, thanks for reading.

8 Responses to “Revision F Prototype updates”

  1. Kean March 8, 2014 at 6:06 am #

    Nice changes!

  2. Fer March 10, 2014 at 7:54 pm #

    Nice changes and new enclosure! thanks!

  3. KarolNi March 11, 2014 at 2:05 pm #

    How about safety now? Most microSD cards have only thin layer of isolator on bottom. Now connecting live wire to common and touching card might be …painful.
    I prefer old card location or some lid covering card slot.

    • James March 11, 2014 at 2:28 pm #

      Excellent point – we struggled with this question a little. Bear in mind that the card is displayed in its ejected position, and that to fully insert or eject the card still requires a tool to poke it in to place. It’s still impossible to touch any metal with a finger. The nearest metal is about 4mm deep within the enclosure.

  4. R March 12, 2014 at 10:09 am #

    Will a tool be provided with the Mooshimeter to remove the uSD card?

    • James March 12, 2014 at 4:17 pm #

      In this context I mean “tool” to be almost anything but fingers. A key, a coin, a toothpick, anything you can use to push in to the slot. A specialized tool will not be provided because a specialized tool is not required.

  5. Angus March 19, 2014 at 8:36 pm #

    Most excellent answer, James. I am so pleased with your work!
    Thank you very much.

Trackbacks/Pingbacks

  1. RevF Hardware Bringup Report | Mooshim Engineering - March 26, 2014

    […] I covered in a previous blog post, the new enclosure moves the parting line between the two halves down to the PCB level to create a […]

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