Chip with simple program for Toy

OK, I understand now. Yeah the new beta has some quirks I've noticed
too. It was really easy to see any topic I posted in, now it doesnt
work right. Some of the new features are cool, but wasn't aware of
this problem. Hope they get it right.

It IS beta afterall though. I tried it ONCE and now whenever I go
to just groups.google.com it uses the beta anyway. Cookies make no
difference. Oh well.

Thanks,

Tom


Rich Webb wrote:

On 19 Jan 2005 07:27:45 -0800, tom@wattservices.com wrote:

I use google because it's easy and everywhere I go. I've used Usenet
since the 80's.

I do not understand why you feel it is wrong to reply
to an old topic. I genuinely wanted to know the answer and the
author
said no e-mail.

It's not "wrong" but posting via the new and "improved" Google Groups
as
you did does not preserve any link to the earlier posts in the thread
except for the subject line. The un-named original poster may not
even
remember that the quoted lines were his. Also, none of the other
replies
will be threaded with your question by most usenet clients that use
the
References line to thread postings, so the other earlier opinions on
the
boards will be missing.

It seems some people rather spend their time complaining then
actually
communicating, which is what this for right? I can't think of any
better use than what I did, so I am lost why you feel this way.

The feelings of ill-will are directed at Google, who seem to have
decided to appropriate the usenet as if it was a part of their
"google
groups."

--
Rich Webb Norfolk, VA

 

[keith]

On Tue, 18 Jan 2005 17:17:42 -0600, John Fields wrote:

On Tue, 18 Jan 2005 21:36:14 GMT, Miles Harris <mazzer@yahoo.com
wrote:

On Tue, 18 Jan 2005 09:38:16 -0600, John Fields
jfields@austininstruments.com> wrote:

On Tue, 18 Jan 2005 14:41:26 GMT, Miles Harris <mazzer@yahoo.com
wrote:

I'm talking about a _perfect_ current source, Junior. Surely even
*you* must have worked that out.

---
Well, maroon, in the context of the thread, everybody knows there's no
perfect current source, so when you don't explicitly state that that's
what you're talking about, the default becomes real current sources
which, like lead-acid batteries and diodes, we can add to the
inventory of devices you've demonstrated you know little about.
---

Wrong again, Junior. It was John Popelish that introduced the current
source in his first response on this thread. It was clear that he was
also talking about a perfect current source:

JP:
If you have a current source (that provides as many volts as it takes
to push a fixed current through a resistance), then, yes.

---
As far as I can tell, JP was expounding on the _concept_ of a current
source, which does assume ideal conditions, much like the
impossible-to-find massless lever, weightless string, and frictionless
air.

....zipless fuck. Though Miles' parents apparently mastered it.

--
Keith

 

[Andrew Holme]

Tom Horsley wrote:

I've been working on a silly gadget using the cut & paste bits
of other circuits technique combined with a large does of
ignorance .

The gadget details can be found here:

http://home.att.net/~Tom.Horsley/phonetale/markII.html

With my breadboarded circuit, I have been observing a
phenomena that my tiny little brain can't figure out.

When I expose the cadmium sulphide photoresistor to light,
my relay triggers once (briefly) as expected and desired.

However, fairly often (not all the time), when I put the
lens cap back over the resistor and block off the light,
the circuit will trigger the relay again.

The only theory I have (with no access to a scope that
can record whats happening at different points and show
me) is that the photoresistor resistance actually bounces
around some as it gets dark rather than simply smoothly
going back up. Could that be it?

Yes, that's correct. The LM339 is very sensitive: it responds to very
small differences between the inputs. As the photocell resistance
passes through the critical threshold, the slightest "bounce" is enough
to momentarily push it back below the threshold. To overcome this, you
should add a little hysteresis by connecting a very large resistor (at
least 100k, maybe even 1M) between the output and the non-inverting (+)
input. The on-off and off-on transitions will then occur at slightly
different points e.g. like a thermostat.

 

[Danny T]

Anthony Fremont wrote:

That said... Only my driving chip would need the crystal

That's right. ;-)

I've not used them before, but I'm sure even I can manage this one...
Connect the crystal to two pins and set the config to use it as per the
datasheet!

Er um, not really. There are other ways to do long delays, but I'm not
sure that I'd say they were nicer. ;-) You would probably want to use
a timer and associated interrupt routine to keep accurate track of
elapsed intervals (like seconds for example). That way, your main level
code could go about it's business without worrying about updating the
seconds ticker at the right time.

That sounds a bit better - so I can get a routine to run every second
accurately, without having to subtract one from my "waitAsecond" routine
every time I add a new instruction? ;-)

Btw, is 4Mhz 4 million instructions per second? Guess I need to make
sure my code (eventually checking for time set buttons, alarm etc.)
doesn't run for more than this time, else my timer interupt will
interupt itself, and then I'll probably get stack overflows (or improper
functioning at least!)
--
Danny

 

[Anthony Fremont]

"Danny T" <danny@nospam.oops> wrote in message
news:41ea4c6a$0$15094$ed2619ec@ptn-nntp-reader03.plus.net...

Anthony Fremont wrote:

That said... Only my driving chip would need the crystal

That's right. ;-)



I've not used them before, but I'm sure even I can manage this one...
Connect the crystal to two pins and set the config to use it as per
the
datasheet!

Don't forget the caps to ground, or it wont start. It's only recently
that I started using the internal osc. It's actually getting to be
fairly usable as the new parts come along. A 16F628 I'm playing with
right now is only fast by about 3.5% according to my 15 year old
frequency counter. This is actually convenient for me since I can use
Timer0 with a prescaler of 4 and get interrupts at almost exactly 1mS
intervals (instead of 1.024mS) without having to reload it every
interrupt.

Er um, not really. There are other ways to do long delays, but I'm
not
sure that I'd say they were nicer. ;-) You would probably want to
use
a timer and associated interrupt routine to keep accurate track of
elapsed intervals (like seconds for example). That way, your main
level
code could go about it's business without worrying about updating
the
seconds ticker at the right time.

That sounds a bit better - so I can get a routine to run every second
accurately, without having to subtract one from my "waitAsecond"
routine
every time I add a new instruction? ;-)

Well, it's not quite that straightforward. You usually count a bunch of
short intervals (like milliseconds) and then do something important when
1000 have gone by. A common housekeeping interrupt loop time is 10mS.
Every 100 interrupts you could add one to a seconds counter. Timer2 is
real good at this kind of stuff, but I like to use it for other things.
Timer0 is kinda weak (only 8 bits), but it's handy. ;-)

Btw, is 4Mhz 4 million instructions per second? Guess I need to make

No, it's 1 million instructions per second. The clock is divided by 4
as every instruction cycle consists of 4 Q states. 4MHz is a nice clock
speed because every (single cycle) instruction takes 1uS to execute.

sure my code (eventually checking for time set buttons, alarm etc.)
doesn't run for more than this time, else my timer interupt will
interupt itself, and then I'll probably get stack overflows (or
improper
functioning at least!)

When an interrupt occurs, the GIE flag is cleared. This prevents the
scenario you described. When the ISR returns, it uses a retfie
instruction which sets the GIE bit again so that another interrupt can
occur. If you forget to clear the flag for the interrupt that you just
processed, then you'll be processing it again as soon as you execute the
retfie. ;-) This is a common mistake for newbies.

 

[Danny T]

Anthony Fremont wrote:

If your clock was losing a minute per day, then you would likely need to
fix the bug in your code. ;-)

*the*? Do you just mean one of them? ;P

If, however, the crystal was running
slow and you were losing a few seconds per day, that would mean you have
too much capacitance. IOW, the bigger the caps the slower the crystal
will run (to a point).

Righto

--
Danny

 

[Miles Harris]

On Tue, 18 Jan 2005 09:38:16 -0600, John Fields
<jfields@austininstruments.com> wrote:

On Tue, 18 Jan 2005 14:41:26 GMT, Miles Harris <mazzer@yahoo.com
wrote:

I'm talking about a _perfect_ current source, Junior. Surely even
*you* must have worked that out.

---
Well, maroon, in the context of the thread, everybody knows there's no
perfect current source, so when you don't explicitly state that that's
what you're talking about, the default becomes real current sources
which, like lead-acid batteries and diodes, we can add to the
inventory of devices you've demonstrated you know little about.
---

Wrong again, Junior. It was John Popelish that introduced the current
source in his first response on this thread. It was clear that he was
also talking about a perfect current source:

JP:

If you have a current source (that provides as many volts as it takes
to push a fixed current through a resistance), then, yes.

Nil points for observation and comprehension again, Jr.

 

[Lord Garth]

"Jim Douglas" <james.douglas@genesis-software.com> wrote in message
news6-dneIVG6xIeW3cRVn-uA@comcast.com...

Where to go for this download? Gotta give this guy credit for taking
"public
domain" stuff, putting it on
CD and making a business out of selling them.

"TJ" <tj@fcox.com> wrote in message
news:sFYHd.28038$sf5.20483@lakeread05...


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=5157510282&refid=sto
re

They are selling a CD to train an electronics technician and you need
virtually no
computer experience....ummm, okay!

 

[Dan Ritter]

Mark Jones wrote:

Or use something much slower than light - ultrasonics.

I don't think that would work. Wouldn't there be too much other sounds,
vibrations of air and weather to mess it up? Microwaves would probably
be small enough and with a computer circuit you could take multiple
readings per second and average it for more accuracy.

 

[Rich Webb]

On Fri, 21 Jan 2005 17:38:26 -0600, "Jim Douglas"
<james.douglas@genesis-software.com> wrote:

Anyone use these? Any recommendations good or bad? I am looking at some that
have Scope, Meter, Spectrum Analysis, etc. Are the "multi-use" type PC
scopes any good? I see some that are down around $200-300? which is in my
price range.

Some of them aren't too bad, although in the $200-300 range you'll not
get any record setters. For one data point, though, some of the higher
end scopes do use Windows as their user interface. Check out Tek's
TDS6000B at http://www.tek.com/site/ps/0,,55-14873-INTRO_EN,00.html

For one possiblity closer to your price range, take a look at
http://www.linkinstruments.com/oscilloscope.htm. I have not used their
o-scopes but I have (and use) one of their PC-based logic analyzers.
Been reasonably happy with it.

--
Rich Webb Norfolk, VA

 

[Fred Abse]

On Wed, 19 Jan 2005 17:51:10 +0000, Rich Webb wrote:

I need to get a new news reader. This one can't kill filter on
"Message-ID: contains 'googlegroups.com'".

I use Pan. That'll do it.

Really trims this group down to size

--
Then there's duct tape ...
(Garrison Keillor)

 

[Jim Douglas]

Jeesh, I wonder if Ben Franklin's friends said the same thing where we would
be today! I say forgot what folks are saying here and try it, so what if it
doesn't work!

"Dan Ritter" <danritter@telus.net> wrote in message
news:bOcId.39738$06.29580@clgrps12...

mike wrote:

gaurav.patil@gmail.com wrote:

hello,
i want to construct a circuit which will be able to measure distance
between two moving cars.The two cars are needed to maintain a fixed
distance between each other.
if the distance between them increases or decreases the circuit
should be able to detect this change and notify the amount of change
in the distance to both cars.
i want to construct this circuit using infrared LEDS ,so if any one
can help me out with this(circuit idea) please mail it to me .


One can only imagine what you're trying to do.
If you're gonna use the information to CONTROL the cars, you're
absolutely (fill in the blank with your favorite expression of
dementia).
You're quite likely to get sued by the estate of the person(s) you kill
using your contraption...assuming you survive. Suggest you get a
different hobby.
mike

Actually I can just imagine that I wouldn't mind a device to tell me how
far exactly the car is behind or in front of me. I wouldn't use it in
repacementment of looking with my eyes though. But it might be nice for
talking about those talegaters that come up behind you. Like "this guy
actually got within 10 feet behind me on the highway" for example.
Perhaps thats an extreme example though.

 

[Rich Webb]

On 19 Jan 2005 07:27:45 -0800, tom@wattservices.com wrote:

I use google because it's easy and everywhere I go. I've used Usenet
since the 80's.

I do not understand why you feel it is wrong to reply
to an old topic. I genuinely wanted to know the answer and the author
said no e-mail.

It's not "wrong" but posting via the new and "improved" Google Groups as
you did does not preserve any link to the earlier posts in the thread
except for the subject line. The un-named original poster may not even
remember that the quoted lines were his. Also, none of the other replies
will be threaded with your question by most usenet clients that use the
References line to thread postings, so the other earlier opinions on the
boards will be missing.

It seems some people rather spend their time complaining then actually
communicating, which is what this for right? I can't think of any
better use than what I did, so I am lost why you feel this way.

The feelings of ill-will are directed at Google, who seem to have
decided to appropriate the usenet as if it was a part of their "google
groups."

--
Rich Webb Norfolk, VA

 

[John Larkin]

On 24 Jan 2005 14:04:40 -0800, dmb06851@yahoo.com (dB) wrote:

I received this by email.

Any problem with directions, then let me know, we are the little ireland
that stuck in the North Sea, just of the coast of Europe, you know the one,
the one who's given more to this world than any other nation in history.

Before we invade you, we insist that you learn to speak and spell
American. Learning a little geography wouldn't hurt, either.

John

 

[Robert Monsen]

seware wrote:

I am wanting to build a power supply and need a bit o' help. I have an
"Electronics for the hobbiest" type book that goes into fair detail on the
subject, but where it talks of filtering and bleeder resistors it speaks of
their use and suggests values for an example power supply but not how to
calculate the values for your own. Their example uses a transformer with a
12.6V 3A secondary wth a full-bridge rectifier. The bridge outputs have 3
1000uF 35V caps in parallel and then a 1K 1/2W resistor in parallel with the
caps for the bleeder. How do I calculate my needs for a transformer with a
15V 5A secondary? A worked example would be nice but I can plug in numbers
if someone will explain the reasoning. I understand that the size of the
bleeder depends on how fast I want to discharge the caps, but I don't know
what kind of time is reasonable. Should I reverse engineer the RC constant
in the example and work forward from that or are their some better rules to
follow? Thanks to all you professionals who sustain the questions of all of
us wannabees.

Steve

The way these things work is that the power line gives a pulse every
1/60 seconds (or 1/120 seconds, if you are using a full bridge with 4
diodes). So, the caps will be 'pumped up' to full voltage that often,
and then power your supply between pulses.

You will probably also use some kind of voltage regulator. If you were
building a 5V supply, for example, you might use a 7805. These
regulators will always require some 'headroom', meaning that the input
voltage must not drop below some minimum for the regulator to maintain
the output voltage. For a 7805, for example, this is usually stated as
3V. Thus, you don't want the input voltage to drop below 8V.

So, the caps get pumped up to 12.6V every 1/120 second, meaning that the
drop from 12.6 to 8V cannot be faster than 1/120 seconds.

Now, you need to decide how much current your maximum is. For a 7805,
for example, the maximum current is about 1A. So,

I = C * (dV/dt)

I = 1A

dV = (12.6-8)

dt = (1/120)

so C = 1A / (4.8*120) = 1812uF

Usually, some fudge is thrown in, so if you use 2,000uF, you'll be safe.

For a bleeder resistor, say you want the thing to discharge in 5
seconds. The rule of thumb is that a resistor will discharge a cap in 5
* RC. So RC in this case is 1. Thus, R = 1/2000uF = 500 ohms. Thus, 470
ohm is a standard value which is near enough.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.

 

[John Fields]

On Thu, 27 Jan 2005 17:33:27 -0600, John Fields
<jfields@austininstruments.com> wrote:

That way you wouldn't have to run the 555 above ground and the
reference would keep the low input to your load at 2.5V while the
battery aged ^^^^
0.25

--
John Fields

 

[krishneo]

Guys Anybody having idea about interfacing serial port in winxp

 

[Bob Masta]

On Fri, 28 Jan 2005 07:49:10 -0500, "krishneo"
<krishnaeie_007@rediffmail.com> wrote:

Guys Anybody having idea about interfacing serial port in winxp

Haven't tried it, but if you don't want to use
the Win32 API you will need to load a special
kernel driver to gain access. The first place
to check for any kind of port info is
Lakeview Research <www.lvr.com>
That should at least get you started.

Best regards,


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

 

[Fred Abse]

On Thu, 27 Jan 2005 10:01:41 -0800, nice_reply_only wrote:

Internet Evangelist R.L. Grossi

s/evangelist/spammer

--
Then there's duct tape ...
(Garrison Keillor)

 

[royalmp2001]

The project is called a ZAPPER pioneered by Dr Hudda Clark and is a
pseudo-medical experimental device that supplies a 39KHz square wave
with 0.25V positive offset to two handhold electrodes, which the
patient holds for a certain duration.

The claim is that parasites, bacteria, molds, and viruses in the body
are killed by this operation.

The circuit is a simple 7555 producing the required waveform from a 9V
battery, so there is no additional circuitry after the 7555 output.

PLEASE PLEASE...How do I add biasing .25V to the output of the 7555?
Please tell....
Thanks