as there are now ~10^8 vlinks in the immediate possession
of MIMEzine folx, I think we need something more
widespread and expandable than 666*...
A pressrelease on the voicemail chip:
Misc. Docs on the chips (we have a 1420):
FCC filing on the v-link (not as useful as ya'd think):
...but it gives us the frequency range: 902-916 MHz...
Ever wonder why we can't find anymore of these things? Check out:
Yes!'s distributors included:
Toyzrus, walmart and target...
so we might want to expand our search.
(i'm assuming folx are still interested in additional units to
under way right here, right now:
you're bright kids, you know how they fit together... anyone recognize
PS> the component side of the daughter board has a whole bunch of lines:
those are ground which merge with the RF shielding that would be covering
it, if we hadn' unwelded the whole thing...
> :Yeah, longer antenna will always result in better reception. However,
> You have to make sure that the antenna is some multiple of the wavelength
> for optimal operation i believe... Been a while since i've touched
> antenna theory though. Q is the in house antenna expert i think...
yes, i think that is right about the wavelength. the antenna has to
least 1/2 the wavelength (that's why AM antenna are so big!) i'll read up
on antenna this weekend and get back to you guys. i don't think it has to
be exactly a mulitple, but that makes it most efficient. (? i'll have to
check again) if you're really chomping at the bit, check out balanis'
(spell?) antenna book. it's the classic. also try ramo, <name i forget
here>, and van dozer 'fields and waves in communications electronics.' or
my EM book. maybe WAY too theoretical and old school, but all are good
books if you're interested.
It has been brought to my attention that what we've been doing
w.r.t. the Vlink jonk is right in line with what this list was created as
a forvm for...
..i tend to agree, even in conflict with my earlier posting..
so nevermind the earlier message, i'm going to pull that group from x.500
and if there is call for something like it later on... we'll take care of
and on that note, I've found out what a bunch of the black boxes on
motherboard of the vlink are. The phatty chip we had handwavingly
assigned as an ASIC is, in reality, a 4-bit microcontroller made at one
point by Samsung... They seem to be discontinued, but i'm in the process
of tracking down docs from the Samsung web weasels.
More info and datasheet URLs to follow when I get back to A^2.
haha, that's gotta suck.
cool... we've sorta started mapping the pins, but it's tough!
pin 1 is definitely Rx
pin 3 should be gnd
pin 5 should be v+
we suspect that one of the last pins (read: end -3, -4, -5) from the end
is the Tx, but not exactly. perhaps things are BPF'd before reaching the
daughter board and reassembled on the other daughter board. FFT? DCT?
would be stranger still, but this remains to be explored. most of the
other lines are control. i'm strongly in favor of the LED hack, since most
of us can't afford scopes like dans.
PS> did you steal the solder sucker from SPLAB the other night? if so,
owe you an ass-kicking, since i was looking for it.
Here's the skinny on some of the various chips in the belly of the beast:
...still waiting on the full
monty details from Samsung re:
the display controller.
256-bit EEPROM (to the right of the SEC LCD controler)
Quad bi-lateral switch (below the 93c13)
General-purpose op-amp (below the cd4066bcm)
PMOS voltage regulator (bottom left of the motherboard)
there are several fairchild semi chips on the daughterboard,
but lookups on the part numbers have turned up nothing
the motorola chip at the bottom of the board:
Low power FM IF (whatever that means ;-)
The fairchild MB1502 from the daughterboard is out of production,
but there is still some info on it, and its replacement part
the national LMX1501A...
its a 1.1 GHz frequency synthesizer, baby:
Just happens to be nothing but 5 AAA NiCad cells wired in series.
of mine wouldn't take a charge so I cracked it open.
The charger produces 13V at 70mA to provide a trickle charge for the
NiCads, and will probably charge just about any NiCad battery pack you
choose to attach it to (i.e. take 4 AAA nicads, populate the included
battery pak, and slap it on the charger). Just don't use it to charge
those Eveready Renewal cells and you should be fine.
I think we could really boost the transmitting range of these bad boys
by using 4 or 5 D cells in a belt pak arrangement :-) but barring that
even AA cells would provide an improvement in current capacity and
extend the range.
Mimezine Tactical Response Corps - West Michigan Unit
Well, Shawn proved to be absolutely correct. Andy and I
didn't want to try strapping on the D cells, but 4 C cells
got us from one end of the atrium to the other (one person
could go out both doors). We also got from the corner of
EECS and the MU to the sidewalk outside of Dow right by the
start/end of the dirt truck path...
Not bad, but still not good
enough! Andy thought we should
use 6V lantern batteries. I think 2 or 3 car batteries with
a voltage regulator should suffice. Just as long as the
regulator doesn't cut the current. Damn the beltpack, full
VLink happy once again...
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