[Community] Status of OpenPhoenux project
Dr. H. Nikolaus Schaller
hns at goldelico.com
Tue Aug 28 14:49:09 CEST 2012
after some time with rare news (holidays - not really for
me but some contributors) I have enough to say for
another status update.
our production company is really cooking our project on
Although I discussed all issues in July with them, they
did need until *today* to start trying the new stencil and
soldering methods. And first results are expected by end
of the week.
The reasons were that they forgot to order something.
That someone was in holidays and after he was back
someone else was in holidays. In the meantime they
did have too much other projects to run.
Unfortunately I have no idea how to come out of this
circle situation except giving them the time they need.
If it were possible I would have switched already. But
they are unfortunately "on the long end of the lever".
Because I can't promise them big numbers of units.
And this is because demand for the GTA04 is not very
high these days.
It is not very high because we don't have units to show
and to sell from stock. And because it is quite expensive
because the number of units aren't high...
So we are trapped.
Finally they know we don't have enough money left
over to move to a different company and start from
scratch, i.e. kick them out of business.
Well, we could take the same company as OpenPandora
is using (in fact we did recommend the alternate company
to them :).
They *have* even solved the DM3730 soldering problems
two weeks ago. Essentially by the same means we know.
But they were much faster.
Because Openpandora has (back)orders which are more
than 10 times as high as ours. It is in the range of several
thousand units per year. This gives much more pull on
such an organization than our small numbers.
So the only news I have is that they are now continuing to
work. But unfortunately no finalization date.
2) Case Kit
But I also have good progress to report for the case kit.
Let's go through the components individually:
We have found a good receiver. Unfortunately it can
not be connected to the GTA04 motherboard since it
has different spring contacts. It looks like this:
So we have this plan:
* if you need a receiver for the GTA04A3/A4 board
there is a Asus spare parts company in Sweden who
appears to be able to supply some:
Someone could organize a group buy for this.
* for the future GTA04A5 board we will design the contact
pads so that it can handle both receiver types.
* 3D data can be made receiver dependent (i.e. 2 different
front covers) or it could be possible to design a small
A (or even the) key component of the Case Kit is a
good and working antenna. Without a good antenna
we don't have a wireless system but a heat generator
even in the vicinity of a base station...
The antenna must be easily connected to the GTA04 board
which is currently optimized for the original GTA01/02
antenna (where nobody has detailed design or production
data). Finally we have found a simple and producible solution
using a PCB and and the smallest pogo pins we could find.
So we have built some prototypes to optimize the
mechanical design and experiment with the electrical
You can see one board using a commercial Pentaband
antenna module mounted on such an adapter board.
Another board has a U.FL connector for measuring purposes
or connecting external antennas.
And two boards carry different experimental PCB antenna
The wire trace is basically similar in shape to the wire
used by the GTA01/02 antennas but must be optimized
for the PCB antenna type. And, it should also better
cover the UMTS 2100 MHz band.
For this goal our RF guy is running simulation after simulation
(using http://www.nec2.org/ ). It is important not only
to reach the 50 ohms impedance, but also have the right
resonance frequencies. And this all depends in a quite complex
way from the geometry of the wire stubs.
So we have to give him some more time to work on the
simulations (anyone experienced in giving a hand?), then
build some samples and do measurements to compare
to the simulations. Finally, we might need another improvement
Anyways, we are on the right track towards a working antenna.
And, one result is already clear: we don't have to make
the antenna much bigger and add any ears or truncheons
to the case...
are available from stock.
d) Vibracall motor
we have found a motor and will solder pogo pins so
that they are easily contacted to the existing pads of
a GTA04 board.
After the original antenna module we had chosen
was discontinued, we have found another one that we
can easily source from running production. It is
12x12mm and has a quite good LNA.
We are also preparing a user's manual that
describes the key dimensions of each component so
that you can use this information to design your own
cases and make the case-kit components really fit.
g) 3D design data
Lukas is working to update the 3D case that can
be ordered/printed through Shapeways.
If you are interested, please please make a "wishlist"
entry so that we know how many units we finally have
to plan for:
Kudos again to Radek, Neil Brown and numerous others
who constantly push forward the GTA04 support in Kernel,
QtMoko, SHR and Replicant!
It is again and again amazing what you have already got
out of this platform.
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