audio recording on IC -help wanted

[John Fields]

On Thu, 28 Feb 2008 15:20:36 -0800 (PST), mad.scientist.jr@gmail.com
wrote:

I need to display the numbers 0-255 in decimal on a 3-digit LED
display for a microcontroller project (it would need to be visible in
the dark). Ideally the display would be inexpensive and not take up
too many uC outputs, but what I am finding is expensive ($30 or more).
Does anyone make an inexpensive 3-digit 7-segment LED module that
accepts serial input from say, a PICAXE or a BASIC Stamp 2? Also I
haven't done anything using serial i/o yet but I saw some displays
that had a "clock" pin (so the controller can sync up the data stream
with the module). Would I need to get a clock module for the basic
stamp to talk to the display module? What would a good one be? Can you
build a reliable clock for less using a 555 timer? I as thinking about
how such a device might work without a clock and thought of a way to
do it with 2 lines output, 0-0 would mean no data, 0-1 would mean here
comes some data, 1-0 would mean low, 1-1 would mean high. The display
module would consist of a microcontroller with 2 inputs and 12 outputs
(3 groups of 4 outputs going to a 7-segment encoder IC to drive each
digit). Is this a decent solution or unnecessary? Any advice or links
to a good example would be appreciated... Thanks.

---
http://www.allegromicro.com/en/Products/Part_Numbers/6275/6275.pdf

http://www.allegromicro.com/en/Products/Part_Numbers/6276/6276.pdf


--
JF

 

[dougd]

For image purposes I normally consider CMOS to be inferior to CCD for
sensitivity and noise but I note that the latest 12meg chip in a
$20000 HD cam uses a CMOS chip aparrently almost the size of a 35mm
film frame.
Anyone know the background and economics of this .
Who makes the chip?
The camera company is called Red can be googled for with "red" HD and
video

 

[PhattyMo]

Hi All,

Does anyone have any data on the HEP 590 (and other HEP IC's?)
I found a few in my parts box,but have no data.

Thanks!

 

Richard

Did he advise them of an entire missing shelf full? If not it's like
reporting a missing horse when what you really saw was an empty stable, not
the best way to get an appropriate response.

I'd like to think of him as a modest man not too interested in stables
and horses, and he only claimed a board for himself. Meanwhile the
problem seems to be sufficiently known at Elektor, see some recent
postings in their forum.

 

[JW]

Hello all,

We've received a reel of 1,000 SRAM parts from PartMiner that were deemed
counterfeit by the folks at Cypress. Due to availability issues in
March we were forced to buy from this broker, even though they've screwed
us in the past with counterfeit parts and I've pleaded with them not to
buy from them (or any broker) again. The failure rate of the chips at
initial test is about 10%. The chips in question are 256kb async SRAMS
marked:

CY7C199D-10VXI
0544 G 04
637944

After contacting Cypress, their response was:

"Based on the information (top marking) that you provided , our lot
history verification showed that it is "not" a Cypress device. Please be
guided that Cypress guarantees only parts that were bought from Cypress or
authorized distributors. Attached is the official Cypress Broker Letter."

 

[Phil Allison]

"Joerg"

Originating audio signal sources have sub uV noise levels at their
outputs - so their associated pre-amps all have to " extricate signals
in the uV region " .


Yeah, I guess that's why you guys use all those low noise opamps like the
LM833 or the NE series.

** They will all "extricate signals in the uV region".

70 years, hmm, maybe I should check out nuvistors as well


** Don't try be smart about stuff you have no comprehension of - or
you will fall flat every time.


I did build audio gear with tubes, back when even Ge transistors were
expensive. Pre-amps, compressors, bigger amps, and one really big amp.
That one had six color-TV H-tubes in it. You could make the plaster rain
down from the ceiling with a few cords on the E-guitar. Sure enough,
shortly after we fired it up the laws came. Luckily they did not check out
how I had done the power transformer. There was none ...

--
Regards, Joerg

http://www.analogconsultants.com/

** Yawn....

What an appalling web site.

Cleary, Joerg = another rabid nut case.



....... Phil

 

[WKW]

I need a source for a few Maxim max6008 2.5 V precision shunt voltage
references or an equivalent unit that will work down to a few uA of
current.

 

I've got 2 'portable computers', with the ribbon cable to the LCD
displays having 15 and similar conductors.

What are the typical configuration and pin-outs of such LCDs ?

Are these 15-odd conductors driving the bit-map, or are bytes being
fed into encoders first ?

I guess it couldn't display non-character/graphics if it didn't address
the pixels individually ?

So if it's say 600 * 480 pixel, it looks as if the address-bus is multiplexed ?

== TIA

 

On 13 Jun, 15:37, b...@FreeNet.Carleton.CA (Gaetan Mailloux) wrote:

Hello

I would need to find a Analog to Digital Converter IC to do data acquisitions
with a Pc computer using the parallel port.

Anyone know some analog to digital converter IC with sampling rate over 400
khz who can be good for that ?

Thank

Gaetan

If you're just curious about PC controlled sampling and looking for
simplicity of design and use, then the Microchip MCP3202 is a cheap, 2
channel, 12 bit A to D and ideally suited for connecting to a PC
parallel port.

http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1335&dDocName=en010532

The chip itself is good to 100000, 12bit samples a second but there is
no way the LPT can run this fast. The port is speed crippled by the
internal PC ISA bus, to a rate (dependant on PC) of maybe 100k to 150k
port changes per second.
In practice the LPT can 'in' and 'out' serial data at about 100k bits
per second.
In the MCP3202 case this translates to about 8000 off, 12 bit samples,
a second. Which is not bad!.
Adding the complexity of a PIC and 4 bit wide LPT transfers, can get
the rate up to about 40000, 12bit samples a second.
In comparison, RS232 is a non starter.

 

[Ian Malcolm]

Ross Herbert wrote:

On Mon, 10 Dec 2007 23:15:53 +0000, Dystopia <xxx@dsl.pipex.com
wrote:


I have a motor home which has the main battery for the engine and an
auxiliary battery to supply the lighting etc in the living area. With
the ignition off a relay switches the auxiliary battery to supply the
living area but when the vehicle is running the relay connects the
auxiliary battery in parallel with the main battery so that it is
charged. The circuit is badly designed because if the auxiliary
battery is flat and the main battery is fully charged (which it

always

is) there is a very high current surge from the main battery to the
auxiliary which blows the 30A inline fuse. I, therefore, need to
insert a circuit to restrict the current to say 20A max.

Can anyone say where there is a suitable circuit diagram on the web?



You need a "smart" dual battery isolator. A simple "back to back
diode" isolator is no good, it does exactly the same as your existing
relay controlled unit.

Guest make a range of smart isolators starting around 70A rating and
you couldn't build your own any cheaper. Most marine or RV dealers
will sell battery isolators.
eg.
http://www.northeastmarineelectronics.com/index.asp?PageAction=VIEWPROD&ProdID=4108

I have a similar setup that cross connects the engine and house battery
on a small yacht. I never have any trouble with it BUT it differs from
the OP's in two crucial details:

1. The relay is rated 80A and fused at 70A (greater than the alternator
rated output). All the wiring is rated over 80A.

2. The alternator output goes to the house battery, as it the one that
needs the most charging.

(This may be more trouble to set up than its worth on a motorhome - the
engine battery can end up low quite easily if the lights are left on
with the house battery still fully charged so the combiner has to be
designed to handle EITHER battery flat with the other one charged. Also
fitting wiring between the batteries and from the alternator to the
house battery capable of handling the full alternator output and
protecting that wiring against short circuits may be a quite difficult
undertaking. The alternator MUST either be machine sensed or the sense
wire moved to the house battery. If the capacity of the house battery is
much greater than the engine battery its worth it though for better and
quicker charging)


Commercial units usually have quite strict restrictions on the MAXIMUM
wire size and MINIMUM length to use which ensure there is sufficient
resistance in circuit to keep the surge current below their switching
rating.

Assuming the existing unit is controlled by the ignition switch,v a flat
battery at nominally 10V (one isn't supposed to take a lead acid battery
below 10.5V) paralleled with a fully charged one at an absolute maximum
of 13.8V only gives 3.8V differential. It needs a total resistance of
0.1266 ohm to limit the current to 30A.

Even 0.1 ohm in series would probably cure the OP's problem.

(WARNING, at 30A a 0.1 ohm resistor will dissipate 90 watts - This will
be a problem if one of the batteries has a shorted cell. Its a lot
simpler to get rid of the heat safely over several meters of wiring
rather than at a single component.)

There are only two occasions (neglecting short circuits) that the fuse
should blow:
If you are trying to pull STARTING current through the relay, e.g. the
house battery is fully charged and the engine one is bad or has a loose
connection.
If your house battery has a shorted cell.


If the existing unit is controlled by either the alternator warning lamp
output or senses the charging voltage, then the battery being charged
gets up to nearly 15V and you either need a little more resistance in
the circuit (0.166 ohm) or a relay rated higher than the alternator
output (the alternator cant hold the voltage on a battery over its
resting level at currents higher than the alternators rated output)

Fitting a Guest unit (or equivalent) rated greater than the vehicles
alternator output, *AND* rewiring to the correct specs for the new unit
would probably be the easiest and safest solution though.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL:

 

[Jamie]

Scott Seidman wrote:

DJ Delorie <dj@delorie.com> wrote in news:xnabgb6t0c.fsf@delorie.com:


Scott Seidman <namdiesttocs@mindspring.com> writes:

Not to mention that the connection through the slip rings is another
thermocouple!!

As long as it's the same thermocouple on both wires, it should be OK.


I don't know what kind of accuracy you need, but for best accuracy,
the thermocouple and thermocouple amplifier must be on the same side
of the slip rings.

That means you're accuracy becomes limited by the cold junction sensor
in the amplifier. If that were acceptable, a simple thermistor could
be used instead of a thermocouple.

Heck, if that were OK, put a battery powered MCU with some DS2762's
and a zigbee radio inside the tank and skip the slip rings completely.
Or an MCU with 20 thermistors.


All good points. I have a number of slip ring systems, and have often
threatened to replace them with telemetry based systems if any of the
rings broke. I'd still need rings for power, as batteries wouldn't be
an option, but that's sort of a different beast, and the ring count would
still go way down.

As to whether the extra thermocouples would do anything bad, if the
'couples were wired directly into the rings, you wouldn't have the same
thermocouples. Same if you extended the 'couples with copper wires.
I've always found thermistors to be more worry-free from such design
considerations.

RTD's also may be a suitable replacement over using thermocouples.

The RTD's can be commutated easily over slip rings.

Just place a small cap across the connection.

http://webpages.charter.net/jamie_5"

 

[DaveM]

"robb" <some@where.on.net> wrote in message
news:13egfsgqgcmbsaa@corp.supernews.com...

i need to replace a SN755518N VFD driver but none of the usuall sources
have it
mouser/arrow/avnet etc...

how do i find a compatible replacement ? or is there an old stock source
somewhere ?
or maybe there is a possiblity that some other obsolete device might have
one that can be nabbed ?? like vcr or tv etc any ideas ?

help greatly appreciated,
rob

Try here:
http://www.ceitron.com/semi/semi.phtml?part=75518

Good place to do business... I've been very satisfied with their merchandise and
prices.
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

"In theory, there isn't any difference between theory and practice. In
practice, there is." - Yogi Berra

 

[ajcrm125]

I'm troubleshooting a Body Control Module (BCM) out of a 2003 Dodge
Minivan and am noticing that all of the components (aside from the
microcontroller) have no datasheets to be found anywhere on the web.
Not even on their manufacturers' websites. Is it that these IC's were
re-labeled specifically for use by Chrysler and that their equivalents
are for sale to the public under another part number?
These aren't asics or anything by any means; op amps, voltage
regulators, hi-side solid state relays etc. Simple stuff. And their
part #'s all end in "AA. Weird.....

Without datasheets I don't see how I'm going to be able to work on
this thing....

 

[James Beck]

In article <7384c8b0-7d42-4312-9bd5-0682b2c130e7
@z18g2000prn.googlegroups.com>, lou002@gmail.com says...

On Oct 17, 10:22 am, James Beck <j...@reallykillersystems.com> wrote:
In article <b9950a9e-747a-43f8-bdce-18565f864fa2
@m3g2000hsc.googlegroups.com>, lou...@gmail.com says...> Anyone out there have experience with an MC6821?

I am working on an upgrade project and the existing circuit uses this
chip.  I specifically need to determing how the IRQ lines get set
active.

Thanks,

http://www.datasheetcatalog.com/datasheets_pdf/M/C/6/8/MC6821.shtml

Thanks, but I have the data sheet, I just do not quite understand how
the IRQ flag sets set... From readind the data sheet it appears as if
the flag can be set when there is a read from a specific address, but
I cannot seen to actually see this happening on a logic analyzer...

No, page 8 has the information you are looking for.

The interrupt is RESET when you read the peripheral data section.

The flags can not be set through the MPU data bus.
They can only be set by transitions on the CA and CB peripheral control
pins.

Look at the information about the control register.
You have to set the CA/CB pins up to generate interrupts on a H to L or
L to H transition and then enable the interrupt.

 

[Paul]

I'm try to figure what the offset voltage temp drift for the Ina116P
op-amp,

Ina116P datasheet:
http://focus.ti.com/lit/ds/symlink/ina116.pdf

At the bottom left side of page 5 is a chart. Looks like there's an
appreciable chance of getting an op-amp that near 20uV/C drift! I
would like to build an electrometer that has extremely low input bias
current and low drift, but that kind of drift seems far to much. If
it's 20uV/C and a gain of 1000 then it's 20mV drift per C, correct?
I'm more used to op-amps like the AD8551, which has a typical drift of
0.005uV/C.


AD8551 datasheet:
http://www.analog.com/static/imported-files/Data_Sheets/AD8551_8552_8554.pdf


I appreciate any help or advice.
Paul

 

[Kevin McMurtrie]

Does anyone know if the TFFC Luxeon LEDs will return? Three months
after Philips claims the LEDs have resumed shipping, all TFFC LEDs still
show as unavailable for public sale. I also don't see any Luxeon
lighting products coming back on the market.

I had 12 of the LXML-PWC1-0090 (cool-white Rebel, 160 lumens @ 700mA)
before the recall. Their combination of low power efficiency, high
power capacity, and tiny size is amazing. One pair flickers at low
power so I guess one cracked. I'd like to use them for portable
illumination if they're reliable now. The extended lack of inventory
makes me suspect that they've reverted to vaporware.

--
Block Google's spam and enjoy Usenet again.
Reply with Google and I won't hear from you.

 

[Michael A. Terrell]

ian field wrote:

Philthy is between the point where he stopped taking his tablets and the
point where they hold him down and give him an injection.

They need to try Cyanide this time.


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

 

[JeffM]

addis.alemayehu@ gmail.com wrote:

hallow their i'm addis

Lostgallifreyan wrote:
Are Google Groups urging people to post self-introductions into Usenet
like it's a big XXXX Anonymous meeting?

No. Neither does Google force first-timers

to read and agree to abide by something like this:
http://www.google.com/search?q=cachehQq8nqqThwJ:groups.google.com/support/bin/answer.py?answer=46492+The.Do's.and.Don'ts.of.Posting.on.Google.Groups+Usenet+Once.you've.read.a.few.hundred.posts

That's the second time in two days now, to this group alone.

Ignorance abounds.

Recently there was another (apparently adult) idiot posting from
Thailand
to a sister Usenet group via Google Groups
who thought he was still at Gmail.

Of course, you're also assuming that children (in Ethiopia)
don't have more online access than they can manage.

 

[Eeyore]

Don Pearce wrote:

Also in the main living rooms I have tried CFLs and rejected them because the light
they give is just too unpleasant to live with.

Even with the current 'warm white' types ?

Graham

 

[JeffM]

cockatoo@ aussieisp.net.au wrote:
The charter for this group:
http://groups.google.com/group/sci.electronics/msg/13651a897337a7a9?q=Charters+misc.industry.electronics.marketplace+Discussions+Advertisement-*-*+only-advertise+sci.electronics.components-Integrated-*-*-*+individual-parts+zz-zz+qq+Discussion