Chip with simple program for Toy

[John Fields]

On Thu, 02 Mar 2006 12:50:09 -0500, Ken C <cprstn54@nospam.att.net>
wrote:

On Thu, 02 Mar 2006 11:29:39 -0600, John Fields
jfields@austininstruments.com> wrote:
This is really a digital millivoltmeter reading the drop across the
shunt and, typically, the input impedance to these voltmeters is
about 10 megohms, so the current in the leads (and, thus, the drop
across them) will be negligible compared to what's going through the
shunt.

Thank you. I still don't think I have enough information to avoid
trial & error.

The voltage drop along the meter leads will indeed be very small in
absolute amount, but not as a fraction of the voltage drop across the
shunt -- which will also be very small.

---
Not true. Let's say the shunt drops 300 millivolts with 30 amps
across it.

With 30 amps going through the shunt, your circuit will look like
this:


30A--->
+V---------+
|
[RL] 300mV
| /
+--------+
| |
[SHUNT] [METER]
| |
GND--------+--------+

and if your meter impedance is 10 megohms, the circuit will look
like this:

30A--->
+V---------+
|
[RL] 300mV
| /
+--------+
| |
[SHUNT] [10MR]
| |
GND--------+--------+

Now, 300 millivolts across 10 megohms will cause:


E 3.0E-1V
I = --- = --------- = 3.0E-8A = 300nA
R 1.0E7R

to flow through the wires connecting the meter to the shunt.

Now, just for grins, lets say that you've got the meter located 1000
feet away from the shunt and you've got them connected up with #24
AWG copper wire. That's a total length of wire of 2000 feet, and a
total resistance of 51.4 ohms, so the voltage that'll be dropped
across the wire will be:

E = IR = 3.0E-8A * 51.4R ~ 1.54E-6V = 1.54ľV,


which is:


1.54E-6V
---------- * 100 ~ 0.00051% of full scale.
3.0e-1V

the meter will have, best case, a resolution of 1 part in 2999,
which is:


100
------ = 0.0333%
2999

so you can see that the effect the length of the wire is going to
have on the system will be miniscule.

I think I need to know either the typical current through the meter
leads or the typical voltage drop across this kind of shunt.

I don't have instruments accurate enough to measure such small
variables. My only recourse is to try different lead lengths and to
see what happens to the readings.

---
The readings are going to stay pretty much the same no matter what
you do, DC wise, but as the length of wire between the shunt and the
meter increases you may wind up with an antenna... :-(

--
John Fields
Professional Circuit Designer

 

[John Fields]

On Thu, 02 Mar 2006 14:11:54 -0600, John Fields
<jfields@austininstruments.com> wrote:

E 3.0E-1V
I = --- = --------- = 3.0E-8A = 300nA
R 1.0E7R

---
Oops... 30nA


--
John Fields
Professional Circuit Designer

 

[Ken C]

On Thu, 02 Mar 2006 14:11:54 -0600, John Fields
<jfields@austininstruments.com> wrote:

so you can see that the effect the length of the wire is going to
have on the system will be miniscule.

Thank you very much. You are a gentleman and a scholar (no kidding!).

Ken C

 

[Jordan]

I don't get it, so no thanks!

Phil Allison wrote:

"Jordan"


** Fuck off - imbecile.





........ Phil

 

[Abstract Dissonance]

"Abstract Dissonance" <Abstract.Dissonance.hotmail.com> wrote in message
news:120c2cpkaf6ib27@corp.supernews.com...

I have sucessfully programmed the 16F688 but when I tried the 18LF4431 it
does not work. I read both specs and they seem to be the exact same(ICSP?)
and I have hooked them up right(pin wise) but when I use winprog to program
the 4431 it always fails(and I did select the right pic in winprog).

Only thing that has changed is that instead of 5.06V rail for the clock
and data lines they dropped to 2.3V or something like that. (But I think
this is in the limit for the LF?)

Only other thing that I can think of has to do with setting the clock in
winpic. Its set at LP but has many other settings... but not sure if this
matters when programming as it uses the clock of the parallel port.

I also have tried to delay up to 150us in winprog on the timing but it did
not work.

Any ideas? I figured the programming method would be the exact
same(Except for pin layout) but something isn't working ;/

Thanks,
Jon

Come on guys!! Can anyone think of a reason why a programmer would work for
the 16F688 and not the 18F4431? As far as I can tell the method is exactly
the same as outlined in the memory specifications of each document(aside
from the communications which is handled by winpic). I'm using Byron's
method by using a tri-state HCT device to buffer the lines between the pic
and the parallel port. I have tried all different settings in WinPic but
nothing helps...

The pin connections are the exact same except for a rearrangement and having
to ground the LVP pin... unless I'm missing something? Do I also need to
ground all the other pins or the AVDD/AVSS too?

(maybe there is something wrong with Winpic though? ;/)

Thanks,
Jon

 

[Si Ballenger]

On 1 Mar 2006 20:25:13 -0800, singlewchildren@gmail.com wrote:

Hi,

I need to get some form of a serial port analyzer. Its not for use
forever, just need to fix a problem with an app that uses the serial
port.

There is a free application on the internet called portmon. It
might give you the data you want.

 

[Jamie]

Bart wrote:

Hi All,
I've been in contact with a guy who has a CNC machine who's controller uses
optocouplers. Here;s a picture:
http://home.fuse.net/consultec/misc/images/optocouplers_.JPG

The one on the right works and there WAS an identical one on the left that
failed and the manufacturer sent a new one that looks different and doesn't
work. You can see the new one on the left does have a different design. Upon
finding the new one doesn't work, the manufacturer sent another, identical
to the first one they sent and it still doesn't work. The guy is convinced
they're sending the wrong style because he's swapped optocouplers and
wherever he puts the original (the one on the right) it works.
Is there something obvious about what is going on? Is one for RS232 and the
other for TTL or 0-20milliamp? Is the output side of the chip the problem?
Is there enough info here to even make a determination?
This is beyond me, hoping someone recognizes the two different circuits and
can give some input.
Thanks in advance,
Bart


hmm interesting devices? i noticed A1 A2 ? these for brush motors

by any chance?
in anycase, i did notice the transistor in the left unit looks
like its not in there correctly if you were to follow the board lay out?


--
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

 

[Bart]

Here is my simple take on it so far,
POINT: The working one (on the right) uses a voltage divider on the input
side so maybe some characteristic of the input side it was designed for
makes
the new/replacement one (on the left) fail immediately up energizing.

COUNTERPOINT: They both use what looks like 1/4 watt resistors and
TO-92 devices which probably means we're just dealing with smaller simple
signals like data transfer. Even the optocouplers I looked up on DigiKey
were rated in the milliamps so I don't think the new/replacement ones are
failing, they're just designed for a different application. Physically seen
differences are apparent on both the input AND output side.

MURPHY'S-POINT: The boards have just one simple task, when one
side is energized (yes, low power) then the other side is allowed to have
IT'S
energy flow (also low power). One board works and the other one doesn't.
Non-working board has transistor mounted backwards from working board.
Non-working board has transistor mounted backward from silkscreen image
on board. Non-working board has never worked, will never work, and
slipped through Brazil's (yes, that's where its made) stringent quality
checks.
My guy has received total of three of these replacement boards, all
identical,
none work.

Did they run out of NPN transistors and thought they'd use PNP and just
mount
it backwards?

Glad I'M not paying for the replacement boards,
Bart






"Bart" <bborb@fusedotnet> wrote in message
news:ee03f$440679a8$d8441fd9$29014@FUSE.NET...

Hi All,
I've been in contact with a guy who has a CNC machine who's controller
uses optocouplers. Here;s a picture:
http://home.fuse.net/consultec/misc/images/optocouplers_.JPG

The one on the right works and there WAS an identical one on the left that
failed and the manufacturer sent a new one that looks different and
doesn't work. You can see the new one on the left does have a different
design. Upon finding the new one doesn't work, the manufacturer sent
another, identical to the first one they sent and it still doesn't work.
The guy is convinced they're sending the wrong style because he's swapped
optocouplers and wherever he puts the original (the one on the right) it
works.
Is there something obvious about what is going on? Is one for RS232 and
the other for TTL or 0-20milliamp? Is the output side of the chip the
problem? Is there enough info here to even make a determination?
This is beyond me, hoping someone recognizes the two different circuits
and can give some input.
Thanks in advance,
Bart

 

[Homer J Simpson]

"Bart" <bborb@fusedotnet> wrote in message
news:41690$4407bfda$45df4eb2$28335@FUSE.NET...

Did they run out of NPN transistors and thought they'd use PNP and just
mount it backwards?

That doesn't work. You have to pull them inside out to reverse them

 

[Deefoo]

"Bart" <bborb@fusedotnet> wrote in message
news:41690$4407bfda$45df4eb2$28335@FUSE.NET...

Here is my simple take on it so far,
POINT: The working one (on the right) uses a voltage divider on the input
side so maybe some characteristic of the input side it was designed for
makes
the new/replacement one (on the left) fail immediately up energizing.

COUNTERPOINT: They both use what looks like 1/4 watt resistors and
TO-92 devices which probably means we're just dealing with smaller simple
signals like data transfer. Even the optocouplers I looked up on DigiKey
were rated in the milliamps so I don't think the new/replacement ones are
failing, they're just designed for a different application. Physically
seen
differences are apparent on both the input AND output side.

MURPHY'S-POINT: The boards have just one simple task, when one
side is energized (yes, low power) then the other side is allowed to have
IT'S
energy flow (also low power). One board works and the other one doesn't.
Non-working board has transistor mounted backwards from working board.
Non-working board has transistor mounted backward from silkscreen image
on board. Non-working board has never worked, will never work, and
slipped through Brazil's (yes, that's where its made) stringent quality
checks.
My guy has received total of three of these replacement boards, all
identical,
none work.

Did they run out of NPN transistors and thought they'd use PNP and just
mount
it backwards?

Glad I'M not paying for the replacement boards,
Bart






"Bart" <bborb@fusedotnet> wrote in message
news:ee03f$440679a8$d8441fd9$29014@FUSE.NET...
Hi All,
I've been in contact with a guy who has a CNC machine who's controller
uses optocouplers. Here;s a picture:
http://home.fuse.net/consultec/misc/images/optocouplers_.JPG

The one on the right works and there WAS an identical one on the left
that
failed and the manufacturer sent a new one that looks different and
doesn't work. You can see the new one on the left does have a different
design. Upon finding the new one doesn't work, the manufacturer sent
another, identical to the first one they sent and it still doesn't work.
The guy is convinced they're sending the wrong style because he's
swapped
optocouplers and wherever he puts the original (the one on the right) it
works.
Is there something obvious about what is going on? Is one for RS232 and
the other for TTL or 0-20milliamp? Is the output side of the chip the
problem? Is there enough info here to even make a determination?
This is beyond me, hoping someone recognizes the two different circuits
and can give some input.
Thanks in advance,
Bart

Oh, I see, you call the whole board an opto coupler, I thought you meant the
6-legged components on the boards. So he swapped boards, not just
components. Ah, language...

--DF

 

[Ken C]

On Thu, 02 Mar 2006 14:11:54 -0600, John Fields
<jfields@austininstruments.com> wrote:

The readings are going to stay pretty much the same no matter what
you do, DC wise, but as the length of wire between the shunt and the
meter increases you may wind up with an antenna... :-(

Will I minimize the antenna effect if I use coax for the signal leads,
like RG-174? There will be RF radiation (1.8-432 mHz) in the
immediate vicinity. RF currents in conductors is a mystery to me and
your experience would be invaluable.

Ken C

 

[Charles Schuler]

How pure? One percent total harmonic distortion?

Most start out with rectangular waves and follow with low-pass filters to remove the harmonics.

 

[Bob Myers]

"nav" <navkush@gmail.com> wrote in message
news:1141397049.594351.147190@j33g2000cwa.googlegroups.com...

hi all
i would be thankful for ur help on power coupling issues in antenna (rf
section )
i need to design a coil for the frequency concerned (f=1/(2pi sqr
root(lc)) and feed the power to antenna.

A coil for what? Coupling to the antenna? If so, coupling
WHAT to the antenna. Loading an antenna element?
Acting as an RF choke in a ground connection? You're
not exactly giving a lot of context for someone to work with,
here.

Bob M.

 

[Andrew Holme]

"nav" <navkush@gmail.com> wrote in message
news:1141397049.594351.147190@j33g2000cwa.googlegroups.com...

hi all
i would be thankful for ur help on power coupling issues in antenna (rf
section )
i need to design a coil for the frequency concerned (f=1/(2pi sqr
root(lc)) and feed the power to antenna.
the problem comes in getting correct inductance coil designing and
testing its value
and secondly
why the point of tapping power for antenna needs to be done at
particular point on coil (i.e. like, one and half turns from positive
feed)
thanking you all.

The choice of inductance is often driven by the required Q. This may be
somewhat arbitrarily chosen e.g. anywhere between Q=5 and Q=10 for a class
C transistor PA stage.

A tapped coil is an auto-transformer. The tapping point controls loading.
If you put the tapping in the middle, the transformation ratio is 4:1.

The dynamic impedance of the (transformed) antenna load across the whole
coil, the loaded-Q and the inductance are related:

Loaded Q = R / wL

w = omega = 2*pi*f

 

[Ken Moffett]

b.clarke@persona.ca wrote in news:1141596214.848191.225350
@u72g2000cwu.googlegroups.com:

Anyone out there, if it is possible make a suggestion as to how to
replace a dpdt with bunch of transistors.

Just wondering if it is possible to do, as I like the neatness of
transistors of a dpdt relay on my PCB.

I think a DPDT transistor configuration is refered to as an "H-bridge".
Goggle that. Standad fair for a uC.

 

[spudnuty]

Glue a key finder on her back.
http://www.ambitiousideas.com/gadgets.htm
Good call DF! I think this is the best idea. You will need to take the

responder apart and waterproof it. I gets around the problem of battery
drain since these devices draw no power until activated. Plus it will
take a minimum of electronic knowledge.
Richard

 

[Rich Grise]

On Sun, 05 Mar 2006 14:03:34 -0800, b.clarke wrote:

Anyone out there, if it is possible make a suggestion as to how to
replace a dpdt with bunch of transistors.

Just wondering if it is possible to do, as I like the neatness of
transistors of a dpdt relay on my PCB.

http://www.maxim-ic.com/SwitchMux.cfm

Have Fun!
Rich

 

[Rich Grise]

On Sun, 05 Mar 2006 19:57:45 +0000, Floatything wrote:

"spudnuty" <spudnuty@lycos.com> wrote in message
Floatything wrote:
Every year, Shelly the tortoise gets lost or manages to escape the
garden.
It can take days to find her. I would like to build a locating device
so
that I can track her down.
The basic requirements are:

a) that the 'transmitter (transponder?) on the tortoise is as small as
possible.

b) that it can be made by an electronics numpty. I have basic
soldering
skills, and can eventually work out a circuit diagram.

Can anyone point me in the right direction?
Floatything (an escapee from uk.rec.sailing)
There are tons of these on the web. Just google "rocket tracking
transmitter" or "model airplane tracking transmitter". There are many
circuits and kits available.
richard

Thanks for that Richard, I have looked briefly at these - but the ones
I've seen so far seem too big for a single Kilotort.

http://www.google.com/search?hl=en&q=animal+tracking+transmitter

They have everything from plans to complete units.

Good Luck!
Rich

 

[Rich Grise]

On Sun, 05 Mar 2006 16:20:35 +0000, Matt J. McCullar wrote:

"Floatything" <chrisknibbs@sinkthespamntlworld.com> wrote in message
news:_TzOf.27372$Ru5.22838@newsfe6-gui.ntli.net...
Every year, Shelly the tortoise gets lost or manages to escape the garden.
It can take days to find her. I would like to build a locating device so
that I can track her down.

Why not just paint her bright green?

Green? Notwithstanding painting a tortoise's shell is very very bad for
the tortise, if I _could_ find safe tortoise paint, I'd go for blaze
orange. ;-)

Then, you can find her at night with a black light. ;-)

Cheers!
Rich

 

[Charles Schuler]

This site will attempt to install files on your computer!