PRC as a amplifier in GPS question.

Hello
CCD-tr75e it is a Sony handycam which doesn't seem to get a mention on
any of the many websites I have visited. Any chance of sending

Jim Lazzaro wrote:

Thanks David for the interesting site.
Jim

quietguy <david1133@REMOVE-TO-REPLYoptusnet.com.au> wrote in message
news:<420594F6.29562BDC@REMOVE-TO-REPLYoptusnet.com.au>...
You could have a look here - you might find a manual that will help

http://www.sonydigital-link.com/manuals/manuals.asp?l=en

David

James wrote:

SONY

"quietguy" <david1133@REMOVE-TO-REPLYoptusnet.com.au> wrote in
message
news:420348FC.B4941E50@REMOVE-TO-REPLYoptusnet.com.au...
Might help if you specified the brand Jim

David

Jim Lazzaro wrote:

I could do with the user manual for this camcorder, perhaps in
pdf
format.
It will stop me from guessing on how to use the many function
controls.
I would like to return the favour with other schems I might
have.
Thank you
Jim

 

[Mike]

Random Data wrote:

The Silicon Chip Luxeon driver about a year ago used the same IC as in
a lot of mobile phone car chargers. I've got a couple sitting at home
waiting for me to finish them off.

Ok, thanks. I looked in a few "car-chargers", and found the MC34063
chip. There is plenty of info on-line, and its easy to modify these
phone chargers for different voltage. Better than buying the chip.

I'm fairly sure the Oatley Electronics module uses something similar,
and they may have schematics up.

Thanks - i found it. Its a bit dissapointing though. It drives the LED
with a voltage regulator and series resistor. It uses a trimpot to
adjust the voltage for the particular LED used. I was hoping for better
ideas on a current regulator!
The design has around a 0.4V drop on the series resistor, so
that a drop of 0.1V on the LED would increase current by 25% .
Are all white LEDs stable enough over time and temperature for that
to work well? Will current go up or down as it gets hotter?

The best alternative I can think of is to loose 1.25V across a
resistor in series with the LEDs, and feed that to the comparator.
That would waste 10% of the power with 3 x 3.6V LEDs (12V output),
but give better current regulation. Or 25% with 1 LED.

Any better ideas?

 

[John Tserkezis]

Mike wrote:

Thanks - i found it. Its a bit dissapointing though. It drives the LED
with a voltage regulator and series resistor. It uses a trimpot to
adjust the voltage for the particular LED used. I was hoping for better
ideas on a current regulator!

You can still use it as a current regulated supply providing it has an
external voltage feedback loop (which it should have).

Use the current limiting resistor in series with the led on the negative
side, off the ground rail.

Feed the hot side of that resistor into the feedback loop, and adjust the
resistor value to suit the feedback voltage reference, and to adjust to a
suitable current for the led.

This way, that resitor serves two purposes, current limiting and current sensing.

If you can get a switcher with a low referece voltage, you can use a lower
value sense resistor, since it's limiting function is rather redundant in this
configuration.

If you use a more flexible switcher, you can even configure it as a voltage
boost regulator, and string all your output leds in series. With this method,
you can easily string leds with a total drive voltage higher than your supply.

Both current regulated, and more efficient than the equivalent simple series
resistor arrangement. More expensive though.
--
Linux Registered User # 302622 <http://counter.li.org>

 

[Oscar]

Mike wrote:

Random Data wrote:

The Silicon Chip Luxeon driver about a year ago used the same IC as in
a lot of mobile phone car chargers. I've got a couple sitting at home
waiting for me to finish them off.


Ok, thanks. I looked in a few "car-chargers", and found the MC34063
chip. There is plenty of info on-line, and its easy to modify these
phone chargers for different voltage. Better than buying the chip.

I'm fairly sure the Oatley Electronics module uses something similar,
and they may have schematics up.


Thanks - i found it. Its a bit dissapointing though. It drives the LED
with a voltage regulator and series resistor. It uses a trimpot to
adjust the voltage for the particular LED used. I was hoping for better
ideas on a current regulator!
The design has around a 0.4V drop on the series resistor, so
that a drop of 0.1V on the LED would increase current by 25% .
Are all white LEDs stable enough over time and temperature for that
to work well? Will current go up or down as it gets hotter?

The best alternative I can think of is to loose 1.25V across a
resistor in series with the LEDs, and feed that to the comparator.
That would waste 10% of the power with 3 x 3.6V LEDs (12V output),
but give better current regulation. Or 25% with 1 LED.

Any better ideas?

The "pucks" sold by Luxeon are sealed in a nice solid epoxy block. Very
reliable and easy. Not much difference in price by the time you've
finished stuffing around.

 

[Mike]

Oscar wrote:

The "pucks" sold by Luxeon are sealed in a nice solid epoxy block. Very
reliable and easy. Not much difference in price by the time you've
finished stuffing around.

The phone chargers are $5, and I have a few spare.
Power-puck is US$20 + post. And bulkier than I want/need.
And i _like_ "stuffing around" with DIY

 

[Mike]

John Tserkezis wrote:

Mike wrote:

Thanks - i found it. Its a bit dissapointing though. It drives the LED
with a voltage regulator and series resistor. It uses a trimpot to
adjust the voltage for the particular LED used. I was hoping for better
ideas on a current regulator!


You can still use it as a current regulated supply providing it has an
external voltage feedback loop (which it should have).

Use the current limiting resistor in series with the led on the
negative side, off the ground rail.

Thats what I meant later in the post, but wasn't so clear.
The problem is that the reference is 1.25V, and I don't know an easy
way to avoid "wasting" that 1.25V at the full ouput current.
But its better if used in a step-up configuration, with a few LEDs in
series.

Feed the hot side of that resistor into the feedback loop, and adjust
the resistor value to suit the feedback voltage reference, and to adjust
to a suitable current for the led.

So R = 1.25V/0.15A = 8.3 ohm.

This way, that resitor serves two purposes, current limiting and
current sensing.

If you can get a switcher with a low referece voltage, you can use a
lower value sense resistor, since it's limiting function is rather
redundant in this configuration.

If you use a more flexible switcher, you can even configure it as a
voltage boost regulator, and string all your output leds in series.
With this method, you can easily string leds with a total drive voltage
higher than your supply.

OK. The common MC34063 chip will do that. It seems the best way for a
bike-lamp. One long string of 4 to 10 x 1/2W LEDs, and it'll run on
any battery I have handy. Maybe even a single LiIon cell.

But the sample circuits seem to be either step-up, or step-down.
So no good for running a single LED from a single LiIon cell.
But thats another project.

thanks for the replies. I've ordered the LEDs.

 

[Boris Mohar]

On 15 Feb 2005 01:14:27 -0800, "David L. Jones" <altzone@gmail.com> wrote:

Jamie wrote:
Khan wrote:

Where can I find "tilt sensor" with analog and/or digital output
indicating
the tilt angle with better than 1 degree resolution?

The Analog Devices ADXL202E is probably the most popular device around.
Fairly cheap too.
I've used it as a three axis tilt sensor, and <1 deg resolution is
easily achievable. Digital PWM output, or analog output with a filter.
http://www.analog.com/en/prod/0,2877,ADXL202,00.html

Dave

How did you temperature compensate it?



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

 

[KLR]

On 15 Feb 2005 05:55:05 -0800, "alitonto" <alitonto@hotmail.com>
wrote:

Hello,
I am trying to work out in particular which component is most likely to
cause a reduced voltage at the supply point to its circuit. I suspect
there is something pulling too much current ahead, becuase when I
disconnect the circuit then the supplied voltage returns to normal
measurement.
Thnsk, Ali

I think we really need a lot more details before anyone can possibly
give a useful answer to that question

]

 

[John Tserkezis]

alitonto wrote:

I am trying to work out in particular which component is most likely to
cause a reduced voltage at the supply point to its circuit. I suspect
there is something pulling too much current ahead, becuase when I
disconnect the circuit then the supplied voltage returns to normal
measurement.

Along with all the other suggestions, you might get lucky if you feel for
not-normally-warm components, which will give you a clue as to which area to
look in.

If the supply in question is fairly low impedance, there won't be enough heat
to feel, so you'll need to cut tracks and remeasure, in an attempt to find
which branch is pulling it down.

At one stage, we were lucky and had use of a thermal imaging camera. You can
spot warmer components quite easily that way. Though not probably the cheapest
specific-use diagnostic equipment...
--
Linux Registered User # 302622 <http://counter.li.org>

 

[David L. Jones]

Boris Mohar wrote:

On 15 Feb 2005 01:14:27 -0800, "David L. Jones" <altzone@gmail.com
wrote:

Jamie wrote:
Khan wrote:

Where can I find "tilt sensor" with analog and/or digital output
indicating
the tilt angle with better than 1 degree resolution?

The Analog Devices ADXL202E is probably the most popular device
around.
Fairly cheap too.
I've used it as a three axis tilt sensor, and <1 deg resolution is
easily achievable. Digital PWM output, or analog output with a
filter.
http://www.analog.com/en/prod/0,2877,ADXL202,00.html

Dave

How did you temperature compensate it?

Didn't need to, the end device was always used in a relatively stable
temperature environment.

Dave

 

[Charles Schuler]

"alitonto" <alitonto@hotmail.com> wrote in message
news:1108475705.096838.197480@z14g2000cwz.googlegroups.com...

Hello,
I am trying to work out in particular which component is most likely to
cause a reduced voltage at the supply point to its circuit. I suspect
there is something pulling too much current ahead, becuase when I
disconnect the circuit then the supplied voltage returns to normal
measurement.

Generally, three things can be considered here. (1) V=IR so if I, the
current, or R, the resistance is too high, V, the voltage drop, will be
excessive. (2) Some power supplies use current limiting which kicks in at a
given point and then they switch over to a constant current mode (as opposed
to constant voltage mode). (3) Some power supplies use fold-back current
limiting which also kicks in at a given point but the current folds back
which makes the voltage drop at the load even more severe.

Could be the load is partly shorted, or a series resistance has gone up in
value, or a faulty connection, or a faulty power supply. Troubleshooting is
usually a process of elimination.

 

[AliTonto]

Thanks guys,
The supply voltage to this circuit is meant to be 5 volts (as per
schematic);
now when I disconect the load (circuit ahead) then should that 5 volts
actually measure a bit higher than stated?
Ali




"Charles Schuler" <charleschuler@comcast.net> wrote in message news:<EJadne0UUsj-7o_fRVn-ug@comcast.com>...

"alitonto" <alitonto@hotmail.com> wrote in message
news:1108475705.096838.197480@z14g2000cwz.googlegroups.com...
Hello,
I am trying to work out in particular which component is most likely to
cause a reduced voltage at the supply point to its circuit. I suspect
there is something pulling too much current ahead, becuase when I
disconnect the circuit then the supplied voltage returns to normal
measurement.

Generally, three things can be considered here. (1) V=IR so if I, the
current, or R, the resistance is too high, V, the voltage drop, will be
excessive. (2) Some power supplies use current limiting which kicks in at a
given point and then they switch over to a constant current mode (as opposed
to constant voltage mode). (3) Some power supplies use fold-back current
limiting which also kicks in at a given point but the current folds back
which makes the voltage drop at the load even more severe.

Could be the load is partly shorted, or a series resistance has gone up in
value, or a faulty connection, or a faulty power supply. Troubleshooting is
usually a process of elimination.

 

[Jerry G.]

What you need is not a 1 pps, but is to have the proper decoder to decoded
the GPS time signal, and then feed the computers with a true time reference.
There are Ethernet, and serial interfaces for this. You should get in touch
with a manufacture of this type of equipment to find out about the necessary
software, and matched GPS system for this.

Using a simple pps is not good, because of one computer jumps off time, it
will not be corrected. It will stay the way is until it is manually
corrected, or it may even jump out again. Sometimes the clock in a computer
goes off time, because it hit a program glitch. The real time clock will not
reset the computer until it is re-started, or until someone comes along and
re-sets the clock.

There are two companies that I have dealt with for the hardware and
software's to do what you want. There is Leitch Video
http://www2.leitch.com/Custserv/products.nsf/WP/Reference , and Torpy Time
http://www.torpeytime.com/main.htm

For our clients, I have used products from both of these manufactures for
time keeping, and have had great satisfaction. We also use many of the
Leitch broadcast systems products, and they are also excellent.

--

Jerry G.
======


<Sunwaesh> wrote in message
news:4217214a$0$1998$afc38c87@news.optusnet.com.au...
Jerry G.,

Thank you for your valuable answer.
In a project I need to have time synchronization between a set of computers
where some of them are networked together on a LAN (no internet) and some
others are running stand alone. I am planning to use the
one-pulse-per-second (1PPS) signal from the GPS receivers. The networked
computers will have one GPS receiver and all the other stand alone computers
will have their own GPS receivers. GPS receivers will generate 1PPS signals
to interrupt the computers to set their internal time clocks. Applications
will use the computer timer (get the time of the day). I want to model (some
how, but I do not know how) the probable variation that a computer clock may
have between 1PPS signals.

Would anyone comment/argue/recommend/suggest/propose how one can model the
variation on a PC clock frequency ?

Regards,

What you are asking would be dependent on the grade crystal materials that
they select for manufacturing them. The crystals have a thermo, and
internal
pressure coefficient factor to deal with. They are also a bit voltage
sensitive, as in part of the feedback circuit employed in the design of
the
oscillator that they are part of.

For home computers, they do not need to use an expensive high stability
type
crystal, as such that is used for precision instrumentation. I would not
be
surprised if the clocking frequency in a home PC machine is drifting about
1% to 2%. As long as everything keeps properly synchronized there will be
no
problem, no matter what the master clocking frequency is.

The time keeping crystal in a PC is different from the one used for the
main
system. The actual real time clock is a separate operation. It is read by
the main system, only at the times where it needs to get the time of day,
and the date data. The time of day accuracy of most computers is about the
same as any low cost quartz watch. I found the time of day on most
computers
to drift as much as several minutes a month, if not corrected. A typical
Timex or Casio watch can do better than 15 seconds per month.

There are softwares available to re-set the clock automatically from some
of
the various time standard services around the world. I believe that XP
comes
with such a software. This can be done over the internet.

If you have the budget you can install a GPS time standard system, and
install the hardware and software in your computer to work with it. The
GPS
antenna would have to be installed at a location where it can clearly see
the sky to receive the GPS satellite data. This type of installation would
result in the most possible accurate time of day standard for a PC
computer.

--

Jerry G.
=====

Sunwaesh> wrote in message
news:4217077d$0$1023$afc38c87@news.optusnet.com.au...
Is there any published research/report about how much "uncertainity"
and/or
variations must be expected on a PC clock frequency ?

 

[Dave Platt]

Jerry G.,

Thank you for your valuable answer.
In a project I need to have time synchronization between a set of computers
where some of them are networked together on a LAN (no internet) and some
others are running stand alone. I am planning to use the
one-pulse-per-second (1PPS) signal from the GPS receivers. The networked
computers will have one GPS receiver and all the other stand alone computers
will have their own GPS receivers. GPS receivers will generate 1PPS signals
to interrupt the computers to set their internal time clocks. Applications
will use the computer timer (get the time of the day). I want to model (some
how, but I do not know how) the probable variation that a computer clock may
have between 1PPS signals.

For those computers which are LAN'ed together, you should certainly
consider running NTP. The commonly-used "ntpd" daemon for Unix and
Linux and etc. will handle the inter-system coordination, and also has
drivers for most GPS and similar external clock systems (including the
PPS input).

The PPS pulses are infrequent enough, and subject to enough jitter,
that the drivers will need to do a fairly significant amount of
low-pass filtering before using the pulse information to calibrate the
internal clock.

Would anyone comment/argue/recommend/suggest/propose how one can model the
variation on a PC clock frequency ?

As I understand it, you're going to be dealing with at least two
separate "clocks" per PC.

One is the on-board date/time-of-day clock chip, which is typically
driven by (or drives) a 32.768 kHz quartz low-power "watch crystal".
These usually seem to have accuracies in the 10-15 seconds per month
range, like a cheap wristwatch. This part of the hardware is designed
to provide a coarse setting of the date and time when the system is
booted, and as I understand it the interface to the chip usually does
not provide a way to read or set the time to any precision greater
than +/- 1 second.

The other is the system's main CPU or bus oscillator, which is divided
down and generates interrupts at a predictable rate (many per second)
and/or is used to run a high-speed counter within the CPU itself.
This is also a quartz-crystal oscillator. It has a higher readout
precision than the clock chip, but you have to be careful about using
it... if you try to track the time-of-day by counting clock interrupts
(as I believe Linux does) you can "lose time" if another device
driver, or the BIOS itself, locks out interrupt processing for more
than a few milliseconds.

These two clocks/oscillators are not correlated with one another as
they're driven by separate quartz crystals. Both are subject to error
and drift due to temperature changes, but there's no guarantee that
the two crystals have identical or even similar temperature
coefficients of change.

The Unix "ntp" daemon software is able to estimate a given system's
amount of clock error and keep a record of the amount of drift (in
parts per million), and will load this value and use it to tweak the
clocking when the system is booted.

As to modelling the error you see on a PC's clock: you're going to
have to deal with several sources of error. To a first approximation,
you can consider the PPS data to be "short-term jittery, but
long-term stable". The 60 Hz powerline frequency is similar...
jittery in the short term due to noise, somewhat drifty over the
course of a day, but quite stable in the average over the long term.

The PC's quartz crystal oscillators are probably at about the opposite
end of the spectrum - quite stable in the short term, with a fairly
constant amount of error (in PPM) in the long term, and some amount of
temperature-related drifting around in the middle.

You might find it useful to review the information on Brooks Shera's
page at http://www.rt66.com/~shera/index_fs.htm - he discusses the
construction of a system which uses a GPS receiver's PPS signal to
discipline a high-stability quartz crystal oscillator.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Sam Goldwasser]

Tim Worthington <eviltim@ifuckinghatespam.optushome.com.au> writes:

I've got a small 5" colour monitor that I'm using a test monitor. It
came with a small degaussing coil but no associated electronics.

This monitor will be moved around a lot and I don't want to have to
degauss it with a degauss wand every time it gets a bit magnitised. So
i'm trying to think of a way to power the coil it already has.

I'm thinking about putting a posister, the coil and a degauss button
in series with the 240v mains available inside the box. What type of
posistor to use? I imagine most would let too much current through
before getting hot enough.

Philips seem to have a large selection (availabe as tv spares) but I
can't find specs anyware online...

The coil is 140mm in diameter and has a DC resistance of 8 ohms

any ideas?

Can't help with specs but all degaussing coils inside TVs and monitors
have a very low resistance and depend almost entirely on the Posistor
for current limiting to a safe value and of short duration.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[Phil Allison]

"Tim Worthington"

I've got a small 5" colour monitor that I'm using a test monitor. It
came with a small degaussing coil but no associated electronics.

This monitor will be moved around a lot and I don't want to have to
degauss it with a degauss wand every time it gets a bit magnetised. So
i'm trying to think of a way to power the coil it already has.

I'm thinking about putting a posister, the coil and a degauss button
in series with the 240v mains available inside the box.

** You need a bit more than that - usually a hefty relay is used to engage
the posistor circuit with a timer to hold it on for 5 seconds or so. The
button just initiates the timing cycle.

What type of
posistor to use? I imagine most would let too much current through
before getting hot enough.

** De-gaussing coil current peaks at around 30 - 50 amps.

Philips seem to have a large selection (availabe as tv spares) but I
can't find specs anyware online...

The coil is 140mm in diameter and has a DC resistance of 8 ohms

** Maybe just find an old PC monitor and remove one from it. But do not
just fit a simple on-off button or you will end up magnetising the tube very
badly.




............. Phil

 

The battery-powered RTC clock is frequently VERY inaccurate,
though.
For reasons I've never had explained to me, they almost always have
a
trimcap on that xtal. Their Q/C processes to set that trimcap
appear

What trimcap? I've never seen one in a PC RTC circuit and, golly,
does
it need it!

Maybe your motherboard collection differs from mine. But every board
I've owned (except some of the laptops) has had a trimcap.

Mystery why they bother to put such fine-tuning on there, since it is
very common to get as much as 10 seconds drift per day!

 

[Dave Platt]

Hey,

1) Where can i find an programm that has an listing or HEX-file for an
PIC16F84 To convert to an processor in the 8051-familie? (for an 80C537)

I did a quick Google search on the phrase "PIC frequency counter", and
the first page was just full of interesting projects of this sort.

http://www.piclist.com/techref/piclist/weedfreq.htm is one such.

You can also go to www.microchip.com and download their AN592
application note, which is for a frequency counter using the PIC16C5x
chips.

2) I look an schematic for an Frequency counter with 8051-processor.

Googling on "8051 frequency counter" shows a link to
http://www.8052.com/codelib.phtml where there is a project of that
sort, I think.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Spehro Pefhany]

On Fri, 25 Feb 2005 18:18:58 -0800, the renowned Peter Bennett
<peterbb@somewhere.invalid> wrote:

On Fri, 25 Feb 2005 07:12:35 +0100, "Christophe"
christophe.vh@tiscali.be> wrote:

Hey,

1) Where can i find an programm that has an listing or HEX-file for an
PIC16F84 To convert to an processor in the 8051-familie? (for an 80C537)

I think chances of finding a program to convert a PIC source code to
8051 are approximately zero.

There once was an assembler by Parallax that converted 8051 type
instructions into (often multiple) PIC instructions. I've never played
with it, and I have no idea how close to 8051 instructions they were.

But, yes, the architectures are so different that any expectation of
taking a program *written* for an 8051 and converting it to PIC is
likely to be false. The idea of the Parallax system was to simplify
the learning curve for 8051 programmers who wanted to try PICs, not to
convert existing programs.

If the program is already in 8051 assembler, it's almost surely best
to stick with an 8051 variant.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Luhan Monat]

Christophe wrote:

Hey,

1) Where can i find an programm that has an listing or HEX-file for an
PIC16F84 To convert to an processor in the 8051-familie? (for an 80C537)

2) I look an schematic for an Frequency counter with 8051-processor.

With thank
Christophe
(Sorry for the bad English)

I could not find a source for 80c587, but PICs are cheap and available.
Why feed a dead horse?

http://members.cox.net/berniekm/super.html

(16 functions including 8 digit frequency counter to 50Mhz)

--
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
http://members.cox.net/berniekm