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Re: 555 Timer Rate for Stepper- Next Counter

 

--- In Electronics_101@..., "Roy J. Tellason"
<rtellason@b...> wrote:
On Tuesday 02 March 2004 04:02 pm, davidglaister wrote:
Hi,

I posted a message a week or so ago asking for advice on the
timing
of a 555 timer to drive a UNC5804 stepper motor driver. With the
advice from this group, and some trial and error I now have the
motor functioning as needed - thanks.

The next thing I would like to do is connect a velleman K8035
up/down counter so I can keep track of the position of the
stepper
motor.
What is this counter, a chip? Something else? I'm not familiar
with the
name you mention.

On the stepper motor circuit the 555 sends a pulse to the UCN5804
that then drives the motor forwards or backwards depending on the
whether pin 14 of the 5804 is fed +5v or 0v.

The counter circuit counts down if wire 8 is pulsed, or up if
wire 9
is pulsed.
There are TTL counter chips which work the same way, and others
that have a
single clock input and a direction input, which probably matches
up with
what you're feeding the motor.

Would it be possible to drive the couter up/down from the
stepper motor
circuit (I hope this makes sense). The problem is wire 8 or 9
would have to
be pulsed depending on the state of pin 14 (diode, transistor?)
Probably easier with a small number of logic gates.

I'm not sure if the wires of the counter circuit require +v or -
v,
the instructions state:

"counting pulses can be applied to the unit by applying +3v to
+12v
pulses with respect to ground"
Sounds like it's looking for a positive pulse.

Tell me more about this counter?
Hi,

Thanks you for the reply.

A link to the counter instructions:


A link to the driver circuit:


As for a counter that has a pulse input and direction input, I have
found this circuit:


But from what I have read on the web, it may not be suitable
beacause of the "debounce" built into the circuit (or PIC).

David


Re: 555 Timer Rate for Stepper- Next Counter

Roy J. Tellason
 

On Tuesday 02 March 2004 04:02 pm, davidglaister wrote:
Hi,

I posted a message a week or so ago asking for advice on the timing
of a 555 timer to drive a UNC5804 stepper motor driver. With the
advice from this group, and some trial and error I now have the
motor functioning as needed - thanks.

The next thing I would like to do is connect a velleman K8035
up/down counter so I can keep track of the position of the stepper
motor.
What is this counter, a chip? Something else? I'm not familiar with the
name you mention.

On the stepper motor circuit the 555 sends a pulse to the UCN5804
that then drives the motor forwards or backwards depending on the
whether pin 14 of the 5804 is fed +5v or 0v.

The counter circuit counts down if wire 8 is pulsed, or up if wire 9
is pulsed.
There are TTL counter chips which work the same way, and others that have a
single clock input and a direction input, which probably matches up with
what you're feeding the motor.

Would it be possible to drive the couter up/down from the stepper motor
circuit (I hope this makes sense). The problem is wire 8 or 9 would have to
be pulsed depending on the state of pin 14 (diode, transistor?)
Probably easier with a small number of logic gates.

I'm not sure if the wires of the counter circuit require +v or -v,
the instructions state:

"counting pulses can be applied to the unit by applying +3v to +12v
pulses with respect to ground"
Sounds like it's looking for a positive pulse.

Tell me more about this counter?


Re: Blood Pressure monitor

HSchwenk_Web.de
 

¿ªÔÆÌåÓý

Hi anmol
I have written an e-mail to the
designer

Thanks for Your help

?

Regards? Heinz

?

----- Original Message -----
Sent: Tuesday, March 02, 2004 6:53 PM
Subject: Re: [Electronics_101] Blood Pressure monitor

Heinz,
????? Sorry couldn't mail earlier. Please check this page for more
info

You will find the 's email address there. Also you can download
the zip file of the full entry from that page.

hope this helps
-anmol

On Sun, 29 Feb 2004, HSchwenk_Web.de wrote:

> Hi Anmol
>
> thanks for Your replay.
>
> I don't understand what kind of sensor is the c4 (capacitive sensor)
> How is it attached to the body ?
> My English is limited I understand the Schematic Diagram
> but about this sensor I am confused.
>
>? Regards Heinz


Re: 555 Timer Rate for Stepper- Next Counter

 

Hi,

I posted a message a week or so ago asking for advice on the timing
of a 555 timer to drive a UNC5804 stepper motor driver. With the
advice from this group, and some trial and error I now have the
motor functioning as needed - thanks.

The next thing I would like to do is connect a velleman K8035
up/down counter so I can keep track of the position of the stepper
motor.

On the stepper motor circuit the 555 sends a pulse to the UCN5804
that then drives the motor forwards or backwards depending on the
whether pin 14 of the 5804 is fed +5v or 0v.

The counter circuit counts down if wire 8 is pulsed, or up if wire 9
is pulsed. Would it be possible to drive the couter up/down from the
stepper motor circuit (I hope this makes sense). The problem is wire
8 or 9 would have to be pulsed depending on the state of pin 14
(diode, transistor?)

I'm not sure if the wires of the counter circuit require +v or -v,
the instructions state:

"counting pulses can be applied to the unit by applying +3v to +12v
pulses with respect to ground"

Thanks again for your help, David


Re: design for 90-240VAC to 20VDC(3A) conversion, am i right?

 

--- In Electronics_101@..., "Bene Tam" <bene-tam@d...>
wrote:
hi all

I am a firmware engineer, recently my power adapter for the laptop
is broken

Although I am going to buy a new one out there, i would like to
find out how to build a simple substitute.

There should be 3 stage, right?? AC-AC, then AC-DC, then DC-DC

stage 1, use transformer, say turn ratio 5:1 to lower the voltage
to 18VAC-48VAC, right?

stage 2, use bridge rectifier to convert the AC to DC, the outcome
will be 24-68VDC, right??

but is there any combined alternative for stage 1 and 2?? seems
some sort of switching technique out there?!

stage 3, use some sort of IC, just those from national semi. or
other MOS switching circuit to convert that to exactly 20VDC3A
output, right?? this stage is the most difficult to me, anyone can
tell me more detail??

Thanks much

Check your current requirements and your voltage requirements.

Most likly, the laptop will run on 12 and 5 VDC like home machines
and possibly, 5 and 3.5 v.

Since you also, PROBABLY do not need anything more than 12 VDC, don't
generate 24VDC on your second stage. Using a LM7812 and LM7805 will
drop the voltage to 12VDC and 5VDC regulated, but will shed a LOT of
heat.

A dual transformer to get 6 and 12 volts will offer a much lower
voltage to start with.

A simple power supply is just AC to AC via the transformers like you
mentioned.

Then a bridge rectifier or 4 diodes arranged in a bridge. This
yields DC voltage.

Add to that a capacitor that is rated for double the voltage you
expect. Search this list for "Mariss" or "80,000" and find the post
that referrs to how to size the capacitor.

Then after cap, run the DC voltge into a voltge regulator such as a
LM7812 to get 12 VDC regulated.

Check the specs for amperage for the voltage regulator(s).

None of this is rocket science and is a good E-101 project.

Dave


Re: Blood Pressure monitor

Anmol Sondhi
 

Heinz,
Sorry couldn't mail earlier. Please check this page for more
info

You will find the desinger's email address there. Also you can download
the zip file of the full entry from that page.

hope this helps
-anmol

On Sun, 29 Feb 2004, HSchwenk_Web.de wrote:

Hi Anmol

thanks for Your replay.

I don't understand what kind of sensor is the c4 (capacitive sensor)
How is it attached to the body ?
My English is limited I understand the Schematic Diagram
but about this sensor I am confused.

Regards Heinz


Re: tv to vga

 

Not necessarily. All CRT VGA monitors are analog input, and most LCD
monitors have analog inputs.

However, you are correct about just getting a TV card. The original
poster would have to build most of a TV plus a computer to do what he
wants. A tuner with control circuits, IF strip, then split up the
received signal into H and V and R, G, and B, then digitize all that
in preparation to digitally rescan it to VGA frequencies.

Alien Steve

--- In Electronics_101@..., "ksrao_iete" <ksrao_iete@y...>
wrote:
you cant do it anyway since monitor contains digital elements if you
wanna do it anyway use tv card available in market.




--- In Electronics_101@..., <av1a@g...> wrote:
Hmm , ....this would be interesting

have you tried www.epanorama.net video section.

imran
-----Original Message-----
From: ejazabidi@y... [mailto:ejazabidi@y...]
Sent: Monday, October 29, 2001 7:59 AM
To: Electronics_101@...
Subject: [Electronics_101] Re: tv to vga


--- In Electronics_101@y..., "yahoo" <yahoo@c...> wrote:
>
> >i need a circuit which convert my monitor into tv receiver.
> >i will be very thankfull.
>
>
> Do you want your VGA monitor receive RF television signals
(like
channels 2-13) or just make a circut to convert NTSC video to VGA?

helo
yes i want my vga monitor receive rf tv signals. will u help me
to
find a circuit for that?
thanx



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Electronics_101-unsubscribe@...



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Service.


Re: "cost reduction is king"

 

In a previous life, before Disney & before downsizing,
I was a video systems designer for ABC. We had a
saying that "There's never enough money to do it
right, but there's always enough money to fix it
later". Eventually the system (control room, intercom
system, truck) worked properly, but it was
frustrating. Now however, with outsourcing produced
projects, you'd better get it right the first time,
because that's the way it's going to be. The cost is
lower, but so is the usability & reliability.



--- peter tremewen <Ptremewe@...> wrote:
The problem with the "cost reduction is
king" approach I have always found, is that when it
eventually does fail, you are the one who wears the
blame for the fault. Clients don't wont to know that
it broke down cause they didn't want to pay a few
extra dollars for surge protection. Whenever a
client comes up to me and says "I can get it cheaper
down at blah, Blah" I simply tell them that I sell
middle of the range equipment and that the slight
extra expense is worth it when you consider the cost
of break down. I consider the few clients I loose
because of this are just not worth the trouble they
will cause latter...... When I am asked to do so, I
have a reputation for producing reasonable quality
reliable equipment..... Most people, especially
those who I have previously dealt with, are willing
to pay just a little bit more for that I have
found......

The Sinister Dragon

Of COURSE surge protection, and a gazillion other
things besides, are in
order. But in most industrial environments, cost
reduction is king, and the
bean counters in the front office get to say which
costs get "reducted" and
which don't.

In other words, that's why we sub a few .10
1N4007s into circuits, and have
quit trying (except for a few notable cases) to
sell large-scale protection
to most industrial clients. They just aren't
interested.

-DM


__________________________________
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Yahoo! Search - Find what you?re looking for faster


Re: design for 90-240VAC to 20VDC(3A) conversion, am i right?

ksrao_iete
 

u r right please proceed with utmost care


Re: Level shifting

 

--- In Electronics_101@..., "ghidera2000"
<ghidera2000@y...> wrote:
--- In Electronics_101@..., "upand_at_them"
<upand_at_them@y...> wrote:
I want to use a Multimedia Card (3.3V, SPI) in a circuit that's
mostly 5V. Is there a simple IC that does the level shifting?

Mike
I was just playing with that sort of thing. Couple possibilities:

Simple way: Run your 5v signal through a resistor and a 3.3 zener
diode to ground. Go from the zener to your 3.3 device. Resistor size
depends on the current requirements of your 3.3 device. If its just
communications then a 10k resistor should be fine.

The slightly more complicated method was to use a 74hc245/244
powered from the 3.3 volt side. Your 5v inputs to it need to run
through some honkin' resistors (like 1 meg) though. The 244 will
latch up to 5v and push your whole 3.3 circuit to 5v if you dont
massively limit the current on the 5v side.

Seeing the 74hct4245 link in the previous message though, I'd say
forget the 245 - much safer with the other chip or the diode method.
The problem with using resistors on signal lines is speed. The inputs
and the traces are largly capacitive so added resistance on digital
signal lines slows down the rise and fall times dramatically.


design for 90-240VAC to 20VDC(3A) conversion, am i right?

Bene Tam
 

¿ªÔÆÌåÓý

hi all
?
I am a firmware engineer, recently my power adapter for the laptop is broken
?
Although I am going to buy a new one out there, i would like to find out how?to build a simple substitute.
?
There should be 3 stage, right?? AC-AC, then AC-DC, then DC-DC
?
stage 1, use transformer, say turn ratio 5:1 to lower the voltage to 18VAC-48VAC, right?
?
stage 2, use bridge rectifier to convert the AC to DC, the outcome will be 24-68VDC, right??
?
but is there any combined alternative for stage 1 and 2?? seems some sort of switching technique out there?!
?
stage 3, use some sort of IC, just those from national semi. or other MOS switching circuit to convert that to exactly 20VDC3A output, right?? this stage is the most difficult to me, anyone can tell me more detail??
?
Thanks much


Re: tv to vga

ksrao_iete
 

you cant do it anyway since monitor contains digital elements if you
wanna do it anyway use tv card available in market.









--- In Electronics_101@..., <av1a@g...> wrote:
Hmm , ....this would be interesting

have you tried www.epanorama.net video section.

imran
-----Original Message-----
From: ejazabidi@y... [mailto:ejazabidi@y...]
Sent: Monday, October 29, 2001 7:59 AM
To: Electronics_101@...
Subject: [Electronics_101] Re: tv to vga


--- In Electronics_101@y..., "yahoo" <yahoo@c...> wrote:
>
> >i need a circuit which convert my monitor into tv receiver.
> >i will be very thankfull.
>
>
> Do you want your VGA monitor receive RF television signals
(like
channels 2-13) or just make a circut to convert NTSC video to VGA?

helo
yes i want my vga monitor receive rf tv signals. will u help me
to
find a circuit for that?
thanx



To unsubscribe from this group, send an email to:
Electronics_101-unsubscribe@...



Your use of Yahoo! Groups is subject to the Yahoo! Terms of
Service.


Re: Converting graphics to web formats

dangermouse
 

Sheesh. Is THAT all?

;o)

-DM

----- Original Message -----
From: "Steve" <alienrelics@...>
To: <Electronics_101@...>
Sent: Monday, March 01, 2004 5:54 PM
Subject: [Electronics_101] Re: Converting graphics to web formats


Really busy. I'm researching everything I need to build a doppler RDF
including microstrip/patch antennas and small loop antennas, gated
integrators, and a load of other stuff that I need refreshers on.
While getting my graphics business shifted over to doing imprinting
(tshirts, mugs, etc). Plus my wife and one of the schools here wants
me to come in and do some science classes. And I am attempting to set
up a video capture/editing computer in my spare time with nearly zero
money. And learning to program PICs for use in props and test equipment.

And that's a small fraction of the pies I have my fingers in.

Look for links on microstriplines, small antennas, and anything else
related to my project.

Alien Steve

--- In Electronics_101@..., "dangermouse"
<dangermouse1956@g...> wrote:
Good man. You've been busy lately, huh?

-DM

----- Original Message -----
From: "Steve" <alienrelics@y...>
To: <Electronics_101@...>
Sent: Monday, March 01, 2004 12:48 PM
Subject: [Electronics_101] Converting graphics to web formats


--- In Electronics_101@..., "dangermouse"
<dangermouse1956@g...> wrote:
You might also have been thinking about Irfanview, also free and
quite good.

-DM
That's the one! I changed the folder named CAD to CAD and Graphics,
moved your link for SmartDraw in there, and put a link to IrfanView.

Alien Steve





Yahoo! Groups Links







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Re: Converting graphics to web formats

 

Really busy. I'm researching everything I need to build a doppler RDF
including microstrip/patch antennas and small loop antennas, gated
integrators, and a load of other stuff that I need refreshers on.
While getting my graphics business shifted over to doing imprinting
(tshirts, mugs, etc). Plus my wife and one of the schools here wants
me to come in and do some science classes. And I am attempting to set
up a video capture/editing computer in my spare time with nearly zero
money. And learning to program PICs for use in props and test equipment.

And that's a small fraction of the pies I have my fingers in.

Look for links on microstriplines, small antennas, and anything else
related to my project.

Alien Steve

--- In Electronics_101@..., "dangermouse"
<dangermouse1956@g...> wrote:
Good man. You've been busy lately, huh?

-DM

----- Original Message -----
From: "Steve" <alienrelics@y...>
To: <Electronics_101@...>
Sent: Monday, March 01, 2004 12:48 PM
Subject: [Electronics_101] Converting graphics to web formats


--- In Electronics_101@..., "dangermouse"
<dangermouse1956@g...> wrote:
You might also have been thinking about Irfanview, also free and
quite good.

-DM
That's the one! I changed the folder named CAD to CAD and Graphics,
moved your link for SmartDraw in there, and put a link to IrfanView.

Alien Steve





Yahoo! Groups Links





Re: what component to use to build a bridge rectifier??

 

¿ªÔÆÌåÓý

??? ??? The problem with the "cost reduction is king" approach I have always found, is that when it eventually does fail,? you are the one who wears the blame for the fault. Clients don't wont to know that it broke down cause they didn't want to pay a few extra dollars for surge protection. Whenever a client comes up to me and says "I can get it cheaper down at blah, Blah" I simply tell them that I sell middle of the range equipment and that the slight extra expense is worth it when you consider the cost of? break down. I consider the few clients I loose because of this are just not worth the trouble they will cause latter......? When I am asked to do so, I have a reputation for producing reasonable quality reliable equipment.....?? Most people, especially those who I have previously dealt with, ?are willing to pay just a little bit more for that I have found......
?
??? ??? ??? ??? The Sinister Dragon
?

Of COURSE surge protection, and a gazillion other things besides, are in
order.? But in most industrial environments, cost reduction is king, and the
bean counters in the front office get to say which costs get "reducted" and
which don't.

In other words, that's why we sub a few .10 1N4007s into circuits, and have
quit trying (except for a few notable cases) to sell large-scale protection
to most industrial clients.? They just aren't interested.

-DM


Re: what component to use to build a bridge rectifier??

dangermouse
 

----- Original Message -----
From: "Roy J. Tellason" <rtellason@...>
To: <Electronics_101@...>
Sent: Monday, March 01, 2004 3:41 PM
Subject: Re: [Electronics_101] Re: what component to use to build a bridge
rectifier??


Though if the industrial environment in question is *that* nasty then
maybe
surge protection is in order, before it gets to the rectifiers...
I had to re-compose myself for a few minutes after reading that comment.
Not because you aren't right, but because you are, and other things...

Of COURSE surge protection, and a gazillion other things besides, are in
order. But in most industrial environments, cost reduction is king, and the
bean counters in the front office get to say which costs get "reducted" and
which don't.

In other words, that's why we sub a few .10 1N4007s into circuits, and have
quit trying (except for a few notable cases) to sell large-scale protection
to most industrial clients. They just aren't interested.

-DM


Re: what component to use to build a bridge rectifier??

Roy J. Tellason
 

On Monday 01 March 2004 02:41 pm, dangermouse wrote:
Perhaps that's true for consumer-type work, but in industrial environments,
which are notoriously nasty (chemically, thermally and electrically) that
1000V PIV is wonderful for preventing failures due to the guy down the hall
starting and stopping his welder and other such stuff.
Oh sure, if I'm gonna buy some I'll probably just go ahead and get the 1000V
parts, the price difference just isn't worth it...

Though if the industrial environment in question is *that* nasty then maybe
surge protection is in order, before it gets to the rectifiers...


Re: what component to use to build a bridge rectifier??

dangermouse
 

You're right, it's 1N4007. When Peter said 4008, I just parroted him rather
than check it for myself.

See? It's someone else's fault. I never make misteaks myself...

-DM

----- Original Message -----
From: "Roy J. Tellason" <rtellason@...>
To: <Electronics_101@...>
Sent: Monday, March 01, 2004 2:39 PM
Subject: Re: [Electronics_101] what component to use to build a bridge
rectifier??


On Monday 01 March 2004 12:21 pm, dangermouse wrote:
I'm not sure if anyone has mentioned this yet, so sorry if I'm just
repeating.

Just be sure that you understand what PEAK inverse voltage means. This
refers to the peak instantaneous value of the AC voltages that you
expect
the diode to see. If you expect the highest voltage to be 120VAC RMS,
for
example, the peak voltage will be about 170V, or RMS voltage x
(sqrt(2)),
and your diodes must be sized to handle that.
Good point, and it's not just the peak AC voltage, but the peak
instantaneous value of the AC voltage applied to one side _and_ whatever
the
capacitor that's typically connected to the other side, which under no or
small load will be just as high. So for 120VAC your cap will charge up to
170V or so, and then when the polarity of the applied AC reversed the
cathode of the diode will be at +170, while the anode can reach -170,
giving a total of 340V across the diode. Some may choose 400V parts but
I'd
feel more comfortable going higher.

Of course, if you follow Peter's advice, which I most certainly do
(they're
cheap and much less likely to fail from some unanticipated transient),
your
1N4008 diode won't much care whether you give it 120V or 170V, as it's
rated for 1000V!
1N4008? My chart only goes up to 1N4007, which is shown as a 1000V part.








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Re: what component to use to build a bridge rectifier??

dangermouse
 

Perhaps that's true for consumer-type work, but in industrial environments,
which are notoriously nasty (chemically, thermally and electrically) that
1000V PIV is wonderful for preventing failures due to the guy down the hall
starting and stopping his welder and other such stuff.

-DM

----- Original Message -----
From: "Roy J. Tellason" <rtellason@...>
To: <Electronics_101@...>
Sent: Monday, March 01, 2004 2:35 PM
Subject: Re: [Electronics_101] Re: what component to use to build a bridge
rectifier??


On Monday 01 March 2004 12:19 pm, Phil wrote:
--- In Electronics_101@..., "Roy J. Tellason"

<rtellason@b...> wrote:
To shop
for cheaper parts only makes a lot of sense when you're buying in
manufacturing quantities, thousands of units at a time, but not
for any sort of hobby use.
I agree but several of the surplus places (gold mine, alltronics,...)
regularly have specials on 1n400x. I picked up 40 1N4004 for a buck
a while back. At those prices its worth it to stock up. though I
think you can get them from digikey for like $.04 in small lots.
pretty minimal cost. I use them in lots of ways.
Not a bad deal, that one. And a 400V part is likely to cover most of
what
we're doing with electronics these days, the higher voltages were only
something I'd use for tube stuff way back when. There was a *real* common
part that was sold under a bunch of different numbers and which had a
rating
of 1000V and 2.5A, I used to buy bags of 25 of them, though I don't
think
I ever quite finished using the last bag completely.

One guy I was talking to a while back said that he didn't even bother to
salvage 1N4001s, but I still see them as being useful, for places like
across a relay coil or similar inductive load, where you don't really
care
what the reverse voltage is as it's never going to see all that much.





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Re: Looking for a mentor

Roy J. Tellason
 

On Monday 01 March 2004 01:44 pm, mattnyc_ wrote:
Hello,

I'm new to electronics and would love a little hands on help. I was
wondering if anyone living in or near White Plains (westchester) or
NYC would be willing to be a mentor.
Heh. I used to live in that county, but I ain't moving back there to help
you out! :-) What is it that you're trying to do?