[Community] Case Kit
Dr. H. Nikolaus Schaller
hns at goldelico.com
Thu Jul 19 16:29:17 CEST 2012
Am 19.07.2012 um 16:20 schrieb Denis Shulyaka:
> 2012/7/19 Dr. H. Nikolaus Schaller <hns at goldelico.com>:
>> Some of you are not only waiting for a GTA04 board but also for the
>> case kit components  so that a 3D printed case gives a complete device.
>> We now have good ideas how to build and connect a new UMTS antenna,
>> but it needs experimentation, simulation and measurements until we can
>> have it mass produced. Please note that getting an impedance matched
>> piece of wire is easy to achieve, but one that really radiates well and
>> efficiently isn't. And an inefficient antenna drains the battery faster than
>> we want...
>> But we are still stuck with a new earpiece receiver (the original one
>> is no longer produced and not even available from over-stock - except
>> one expensive source having access to Asus spare parts). And contacting
>> it to the GTA04 board is also very difficult (there are only two small
>> copper+gold blobs for miniature springs - too small to add some connector
>> and too risky to solder some wires).
>> And - unfortunately - the replacement GPS antenna we had choosen
>> to buy from DigiKey was discontinued by the manufacturer. Most likely
>> because the low noise amplifier transistor went out of production.
>> So as simple as it may look, so difficult it is to synchronize these parts
>> and keep the price low. Well, we could now start to design our own GPS
>> antenna module, but we know that you already are moaning how expensive
>> everything is. Getting something from mass production is always cheaper
>> than adapting and customizing components to our needs.
>> If the mass produced thing fulfills our needs... For GPS would be easy
>> if we could get some 15x15mm >20dBm with 50mm U.FL cable from
>> a big distributor.
>> : http://www.handheld-linux.com/wiki.php?page=GTA04%3ACase%20Kit
>> Community mailing list
>> Community at openphoenux.org
> Hi Nikolaus,
> We don't have to match the exact dimensions of the original modules
> since we are designing the case ourselves. Would it be easier if we
> don't limit ourselves to the same dimensions?
Not much. Of course dimensions are not required to match the originals
The problem is that a broad availability of components starts
at much bigger dimensions. I.e. speakers at 15mm x 5mm. Or GPS
modules at 25x25 mm. This results in very clumsy or strange case designs.
E.g. the replacement GPS module we had choosen was 12x12mm while
the original is 15x15 (or 15x20). This can be addressed by the 3D data.
And for the earpiece, if the new component is too thick, you always have
a strange bulge on the front plate above the display. So it has some limits
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