Op amps problem Gain Calculation

[Dave VanHorn]

The STK boards are general purpose development tools.
The Mavric is a designed for just the one processor.

Depends on what you want.

Both will work with AVR Studio, but with the Mavric, you'll need a
programmer, like an AVRISP.

If you want a little board that you can embed in your project, then the
mavric is a better choice.
If you want to work with many different AVRs, then the STK is better.

 

[Coupon Hunter]

http://2xo.net
The Clock People

 

[CJunk]

"~~ VerilogMan ~~" <zoroux7@rogers.com> wrote in message
news:R-CdneomhMyRLD7cRVn-3Q@rogers.com...

Hello,
I am thinking of buiying this graphic display.
http://www.crystalfontz.com/products/12864cp/index.html#CFAX12864CP1WGHTS
It has a 4 analog I/O for the touch screen, and 18 I/O (the specidications
are on the link "Data Sheet")
I have a VERY hard time trying to figure the best microcontroller to
interface it with a desktop computer on the serial port.
If you could take a look at http://dkc1.digikey.com/CA/PDF/C043/P4.html
(Microcontrollers section) and tell me wich one is the easiest / most
efficient, i would appreciate big time !
Thanks guys!

I am not much help with that. One thing I know. is BECARFULL buying from
Digi Key

I am in australia and they charged me $87US($120AUD) for a Digi Key card
board Box. the parts where around $30US.

I have gotten things from the US in the post for shit loads cheaper airfare
than that. Digi key did end up giving me half the shipping cost back,
after trying to rip me off. so in the end I still paid $45US for a card
board box. legal scammers. Basically they sell card board boxes and throw
in a few electronic components. But that might only be if you live in an
other country. maybe they have a mentality of 'screw people in other
countries besides the USA'

anyway....be carefull

 

[Mark Jones]

mark thomas wrote:

The artist formerly known as Dave VanHorn wrote:

|
| Both will work with AVR Studio
|


Is that free software?

See http://www.atmel.com/dyn/products/tools_card.asp?tool_id=2725
or http://www.avrfreaks.net

 

[CJunk]

"Mark Jones" <abuse@127.0.0.1> wrote in message
news:sJOdnet3IIyKuSrcRVn-vA@buckeye-express.com...

CJunk wrote:
"~~ VerilogMan ~~" <zoroux7@rogers.com> wrote in message
news:R-CdneomhMyRLD7cRVn-3Q@rogers.com...

Hello,
I am thinking of buiying this graphic display.

http://www.crystalfontz.com/products/12864cp/index.html#CFAX12864CP1WGHTS
It has a 4 analog I/O for the touch screen, and 18 I/O (the
specidications
are on the link "Data Sheet")
I have a VERY hard time trying to figure the best microcontroller to
interface it with a desktop computer on the serial port.
If you could take a look at http://dkc1.digikey.com/CA/PDF/C043/P4.html
(Microcontrollers section) and tell me wich one is the easiest / most
efficient, i would appreciate big time !
Thanks guys!




I am not much help with that. One thing I know. is BECARFULL buying
from
Digi Key

I am in australia and they charged me $87US($120AUD) for a Digi Key card
board Box. the parts where around $30US.

I have gotten things from the US in the post for shit loads cheaper
airfare
than that. Digi key did end up giving me half the shipping cost back,
after trying to rip me off. so in the end I still paid $45US for a
card
board box. legal scammers. Basically they sell card board boxes and
throw
in a few electronic components. But that might only be if you live in
an
other country. maybe they have a mentality of 'screw people in other
countries besides the USA'

anyway....be carefull



Hi, I'm from the US and I've ordered many things from Digikey and
have never had a problem. Maybe that is an exception, but what exactly
do you mean they "charged you for the box." Are you saying that
Digikey charged $87 for shipping, or "shipping and handling", or
"handling," or "Excise tax," what?

I can't imagine shipping a parcel from the US to Australia would
cost more than $25- unless you ordered a 500-pound item? Where exactly
is the error?

That said, I have heard of some exporting issues with Digikey.
Thanks to our wonderful leadership and legal system, every package
that enters or exits the US is subject to extreme scrutiny. I heard
where someone in Canada was ordering some parts to make hobby kits and
Digikey wrote them a legal letter asking 20 questions about the exact
nature of the hobby kits. Digi-key would not ship until they recieved
a valid, legal response. We can argue about the intent, or if anyone
actually follows another country's laws. But the problem might not be
Digikey's fault per se, they could have simply been following the
current export laws.

Some would say, with all the terrorist activity, that the US might
be taking a defensive posture towards other nations. I wouldn't say
that's so personally. I have always considered Australia a beautiful
and friendly place. So I doubt you or Australia is being singled out
specifically.

So if anything, join with the rest of the world in badmouthing the
US, and understand that unless Digi-key made a gross error, they were
probably following yet another stupid law.

-M

Actually Digi Key threw the questions at me also at first.......that wasnt
much, just following procedure.

the items weighed no more that 9 ounces...but they charged me for 2lbs
which they say is the reason for the extra expense. Of course no body would
actually like paying so much for a cardboard box.. I know I have gotten
things much heavier and much less expensive in shipping. My original post
said 'be carefull' thats all. ... The parts I bought cost around $37.00
us and the box cost $87.00 anyone with half a brain would know to at
least double check with the customer first to see if they understand that
that is what they will be charged for shipping. At least have some sort of
customer relations. anyway...like I said....be carefull to the original
poster. If they live in US, probably no problem

 

[Mark Jones]

CJunk wrote:

"Mark Jones" <abuse@127.0.0.1> wrote in message
news:sJOdnet3IIyKuSrcRVn-vA@buckeye-express.com...

CJunk wrote:

"~~ VerilogMan ~~" <zoroux7@rogers.com> wrote in message
news:R-CdneomhMyRLD7cRVn-3Q@rogers.com...


Hello,
I am thinking of buiying this graphic display.

http://www.crystalfontz.com/products/12864cp/index.html#CFAX12864CP1WGHTS

It has a 4 analog I/O for the touch screen, and 18 I/O (the

specidications

are on the link "Data Sheet")
I have a VERY hard time trying to figure the best microcontroller to
interface it with a desktop computer on the serial port.
If you could take a look at http://dkc1.digikey.com/CA/PDF/C043/P4.html
(Microcontrollers section) and tell me wich one is the easiest / most
efficient, i would appreciate big time !
Thanks guys!




I am not much help with that. One thing I know. is BECARFULL buying

from

Digi Key

I am in australia and they charged me $87US($120AUD) for a Digi Key card
board Box. the parts where around $30US.

I have gotten things from the US in the post for shit loads cheaper

airfare

than that. Digi key did end up giving me half the shipping cost back,
after trying to rip me off. so in the end I still paid $45US for a

card

board box. legal scammers. Basically they sell card board boxes and

throw

in a few electronic components. But that might only be if you live in

an

other country. maybe they have a mentality of 'screw people in other
countries besides the USA'

anyway....be carefull



Hi, I'm from the US and I've ordered many things from Digikey and
have never had a problem. Maybe that is an exception, but what exactly
do you mean they "charged you for the box." Are you saying that
Digikey charged $87 for shipping, or "shipping and handling", or
"handling," or "Excise tax," what?

I can't imagine shipping a parcel from the US to Australia would
cost more than $25- unless you ordered a 500-pound item? Where exactly
is the error?

That said, I have heard of some exporting issues with Digikey.
Thanks to our wonderful leadership and legal system, every package
that enters or exits the US is subject to extreme scrutiny. I heard
where someone in Canada was ordering some parts to make hobby kits and
Digikey wrote them a legal letter asking 20 questions about the exact
nature of the hobby kits. Digi-key would not ship until they recieved
a valid, legal response. We can argue about the intent, or if anyone
actually follows another country's laws. But the problem might not be
Digikey's fault per se, they could have simply been following the
current export laws.

Some would say, with all the terrorist activity, that the US might
be taking a defensive posture towards other nations. I wouldn't say
that's so personally. I have always considered Australia a beautiful
and friendly place. So I doubt you or Australia is being singled out
specifically.

So if anything, join with the rest of the world in badmouthing the
US, and understand that unless Digi-key made a gross error, they were
probably following yet another stupid law.

-M


Actually Digi Key threw the questions at me also at first.......that wasnt
much, just following procedure.

the items weighed no more that 9 ounces...but they charged me for 2lbs
which they say is the reason for the extra expense. Of course no body would
actually like paying so much for a cardboard box.. I know I have gotten
things much heavier and much less expensive in shipping. My original post
said 'be carefull' thats all. ... The parts I bought cost around $37.00
us and the box cost $87.00 anyone with half a brain would know to at
least double check with the customer first to see if they understand that
that is what they will be charged for shipping. At least have some sort of
customer relations. anyway...like I said....be carefull to the original
poster. If they live in US, probably no problem

Still, like you say it would be very bad business practice to "hide"
any extra fees like this, if that's really what happened. I'm not sure
why Digi-key or any other company would charge such an outlandish
amount unless it was just some kind of weird error or
misunderstanding. If it happened to me, I'd write the company and ask
them to explain the charges in detail. (Postal mail is considered
"official correspondence" in the US.) It's not like Digi-key has the
lowest prices anyways, they should have free shipping. I just ordered
some one-off parts from Hong Kong and the shipping and handling was
$12 - why on earth would it cost 4x that for an Australian?

Better luck next time, mate.

-M

 

[~~ SuperMan ~~]

"CJunk" <cjunk@bigpund.net.au> wrote in message
news:0xttd.63459$K7.28861@news-server.bigpond.net.au...

"~~ VerilogMan ~~" <zoroux7@rogers.com> wrote in message
news:R-CdneomhMyRLD7cRVn-3Q@rogers.com...
Hello,
I am thinking of buiying this graphic display.
http://www.crystalfontz.com/products/12864cp/index.html#CFAX12864CP1WGHTS
It has a 4 analog I/O for the touch screen, and 18 I/O (the
specidications
are on the link "Data Sheet")
I have a VERY hard time trying to figure the best microcontroller to
interface it with a desktop computer on the serial port.
If you could take a look at http://dkc1.digikey.com/CA/PDF/C043/P4.html
(Microcontrollers section) and tell me wich one is the easiest / most
efficient, i would appreciate big time !
Thanks guys!



I am not much help with that. One thing I know. is BECARFULL buying from
Digi Key

I am in australia and they charged me $87US($120AUD) for a Digi Key card
board Box. the parts where around $30US.

I have gotten things from the US in the post for shit loads cheaper
airfare
than that. Digi key did end up giving me half the shipping cost back,
after trying to rip me off. so in the end I still paid $45US for a card
board box. legal scammers. Basically they sell card board boxes and throw
in a few electronic components. But that might only be if you live in an
other country. maybe they have a mentality of 'screw people in other
countries besides the USA'

anyway....be carefull

Thanks I did not buy it from them , but from BDmicro.net

 

[J. Mark Wolf]

Ryan Kremser Wrote:

First of all the actual project is an bowling arcade game type thing
(http://www.pinrepair.com/bowl/goldmed3.jpg) its easier to see tha
to
explain. So the updates would only occur to update scores which asid
from
when it happens isn't a huge time issue. (ex takes a second to update)
The
solution that you mentioned before would definatly work for me, I"
just
wondering what kind of prices i should expect to pay for that setup.
Just
to clarify all the inputs are going to be incoming through a ps2 por
to the
computer and i'll be updating scores / lighting background / strik
lights
ect. with these outputs.

BasicMicro (www.basicmicro.com) makes a standalone 40-pi
microcontroller, called the ATOM, programmed in BASIC via the PC seria
port. It will do what you want, faster and easier than anything else

--
J. Mark Wolf

 

[Jim Thompson]

On Sat, 18 Dec 2004 14:16:44 +0800, "Jacky Luk" <jl@kngiht.com> wrote:

Sorry for cross posting but I need instant response.
My assignment is due this wednesday and wondering someone would help. In
PSpice, I need to setup a 1MHz Digital Clock, I used DSTM modules, I need
some delay time and also initial values of the clock, the only thing I
couldn't find is the frequency. Could anyone shed some lights on this? can i
generate the clock using on/off time? Thanks
Jack

You're using the wrong digital part... use DigClock. If you use
STIM1, you'll have to itemize *every* transition.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[John Popelish]

pil wrote:

I need to control a simple heating element which will run off 12Vdc. It does
not need to get very hot.

I need to make it variable. At the moment I have a 555 running in astable
mode pulsing two MJ13005 transistors which are directly connected to the
element. The transistors seem to get too hot. What other methods can I use?

My element usualy are a bunch of fine stranded copper wires and the one I am
currently using has a resistance of 5ohms.

I need to run this off 12Vdc.

I think the power transistors you are using are high voltage, low gain
types. So they need a lot of base current to get fair saturation. If
you replace them with a low resistance N-channel mosfet, that should
run much cooler. They are also much simpler to connect to the 555.
The gate can be connected directly to the 555 output.

Go to Digikey and find the data sheets for IRFZ44V, IRF540, IRF3704
for examples that should work. One of these can handle your load with
no heat sink.


--
John Popelish

 

[Anthony Fremont]

"pil" wrote:

I need to control a simple heating element which will run off 12Vdc.
It does
not need to get very hot.

I need to make it variable. At the moment I have a 555 running in
astable
mode pulsing two MJ13005 transistors which are directly connected to
the
element. The transistors seem to get too hot. What other methods can I
use?

Are you using the transistors in parallel? What frequency is your 555
running at? Duty Cycle? Schematic?

All that aside, worst case gain for that transistor is only 8 (Ic=2A)
which means you will need to supply at least 300mA (each) of drive into
the base to turn the transistors on all the way. AFAIK, the 555 can't
supply that much current by itself. What you need is a nice MOSFET,
preferably one that uses a "logic level" input.

My element usualy are a bunch of fine stranded copper wires and the
one I am
currently using has a resistance of 5ohms.

 

[Chris W]

loedown wrote:

The easiest way to figure it out is like this

the 3.5 mm plug at the tip will have 3 distinct sections, seperated by
plastic between them

http://www.vandenhul.com/artpap/wiring.htm half way down the page

the two braid from the wires to the RCA plugs are connected together and
then connected to the sleeve of the 3.5 mm plug.

The thin white wire is connected to the tip of the 3.5 mm plug

The thin red wire is connected to the ring of the 3.5 mm plug

Paul

Be a little bit careful here. If the microphone (3.5mm)plug is to be
plugged into the PC soundcard Mic jack, then one of the wires will be a
Bias voltage to power an electret mic.

Chris

 

Couldn't find much on your transistors.
2 things, Use a better transistor like a MOSFET that has a low switched
on resistance.
2nd, use the pulse width function of the 555 to adjust the temp. you
will only need one transistor instead of 2 drives.
A predrive may be needed. You are running about 2.5 amps
There are many devices out there that would work I would get one about
5 amps and a med. heat sink.
Mr. Eric Spain

 

[Pasquale]

My connection is a microphone into a small stereo pre-amp, out to a DV
camcorder. How can I reduce or get rid of the little bit of signal noise?


Roger Johansson wrote:

Pasquale <spdrweb@NOTHNXtelusplanet.net> wrote:


I am now using a Stereo Pre-Amp and I am getting a little bit of signal
noise. Is there something you or anyone can suggest to reduce it?



You have not told us what you are trying to connect to what, you only
told us about a connector.

We need more details to be able to help you more.

 

[Pasquale]

My set up is a microphone connected to the adaptor I made with the 3.5mm
female jack and dual female RCA's into a small stereo pre-amp via an RCA
cable, out to a DV camcorder.

How can I reduce or get rid of the little bit of signal noise?


Roger Johansson wrote:

Pasquale <spdrweb@NOTHNXtelusplanet.net> wrote:


I am now using a Stereo Pre-Amp and I am getting a little bit of signal
noise. Is there something you or anyone can suggest to reduce it?



You have not told us what you are trying to connect to what, you only
told us about a connector.

We need more details to be able to help you more.

 

[Roger Johansson]

Pasquale <spdrweb@NOTHNXtelusplanet.net> wrote:

My set up is a microphone connected to the adaptor I made with the
3.5mm female jack and dual female RCA's into a small stereo pre-amp via
an RCA cable, out to a DV camcorder using the RCA to 3.5mm cable
supplied with the camcorder.

How can I reduce or get rid of the little bit of signal noise?

It depends on exactly how much noise you have there.

It is impossible to get rid of all noise, you can only get it a lot lower
than the audio signal.

How much lower depends on the quality of the microphone and the preamp.
It could be the mic preamp which is to noisy. Is it a real mic preamp?

You should test the setup by singing into the mic, adjust levels for
optimum quality and check how much noise there is compared to the audio
signal. Can you hear the noise through the audio signal, is it at a disturbing level?

When you do not sing into the mic and turn amplification up to max you
will always hear noise, but that is not a normal way of using a
microphone.

There is a device called noise gate which blocks the noise from the
microphone when you are not using it.



--
Roger J.

 

[Pasquale]

I'll see where I can find a noise gate, any suggestions?

Also, is it true that a capacitor would reduce noise? If so, how would
it be done?


Roger Johansson wrote:

Pasquale <spdrweb@NOTHNXtelusplanet.net> wrote:


My set up is a microphone connected to the adaptor I made with the
3.5mm female jack and dual female RCA's into a small stereo pre-amp via
an RCA cable, out to a DV camcorder using the RCA to 3.5mm cable
supplied with the camcorder.

How can I reduce or get rid of the little bit of signal noise?


It depends on exactly how much noise you have there.

It is impossible to get rid of all noise, you can only get it a lot lower
than the audio signal.

How much lower depends on the quality of the microphone and the preamp.
It could be the mic preamp which is to noisy. Is it a real mic preamp?

You should test the setup by singing into the mic, adjust levels for
optimum quality and check how much noise there is compared to the audio
signal. Can you hear the noise through the audio signal, is it at a disturbing level?

When you do not sing into the mic and turn amplification up to max you
will always hear noise, but that is not a normal way of using a
microphone.

There is a device called noise gate which blocks the noise from the
microphone when you are not using it.

 

[Pasquale]

see below...

Walter Harley wrote:

"Pasquale" <spdrweb@NOTHNXtelusplanet.net> wrote in message
news:7EEBd.41149$Y72.19723@edtnps91...

I'll see where I can find a noise gate, any suggestions?

Also, is it true that a capacitor would reduce noise? If so, how would it
be done?


You're throwing equipment at a problem when what you need to do is
understand the problem. That almost never works, and almost always costs
more than solving the problem the right way. A noise gate would cost you
more than getting the right kind of microphone and/or preamp. And anyway,
all it will do is reduce the noise when there is no signal; it will not do
anything about the situation when there is a signal. And no, a capacitor
will not reduce noise.

You still have not adequately described the problem you have. In
particular, please answer ALL of the following questions:

What is the microphone you are using?
What kind of connector does it have?

I have a Universal Microphone with 1/4" jack and the adaptor to 3.5mm.

Do you have any reason to believe that it is intended as a general-purpose
microphone, or is it intended to mate with some particular piece of
equipment (that is, did it come as an accessory to some other piece of audio
gear such as a tape recorder)?

On the package it says it can be used with karaoke, camcorders, portable
stereos, etc.

What is the camcorder you are using?

Panasonic. Just purchased a couple of weeks ago. FYI... Model PV-GS200.

What audio inputs does it have? (It might have more than one - for
instance, it might have both line inputs and an auxiliary mic input.)
What kind of connectors does it use for its audio inputs?

It has A/V in/out 3.5mm(?) jack. With the camera came a A/V cable with
video, and left and right RCA on one end and the 3.5mm plug on the
other. I am getting the video no problem. As for the audio, I am getting
sound, I just need it to be amplified.

I put together a adaptor cable to go from the 3.5mm microphone jack to
the dual RCA ends. I think it may be from here where I am getting the
static/hum/noise. It seems that if it is held right the noise is pretty
much gone. Maybe poor solder or bad connection to the tail of the
microphone jack (ground).

The way I did the soldering was:

- RCA white inner core wire to the silver tab of the mic jack
- RCA red inner core wire to the copper tab of the mic jack
- copper wire surrounding each are both solder to the tail of the mic jack

Are they intended for line level or mic level signals, and if the latter, do
they provide DC supply voltage for an electret mic?


Most likely, your problem is that are trying to use an electret type mic,
which has a little preamp built into it, and it needs DC supply voltage to
be provided by whatever it's plugged into; and your camcorder inputs are
intended for line level signals rather than a mic. In this situation, a
preamp will not help unless it is intended for that sort of mic. But, based
on what you've said so far, there is no way to tell if that is actually the
problem. You need to answer the above questions and then people might be
able to help you.

 

[Walter Harley]

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:yMKdncr78NwiO0rcRVn-vQ@speakeasy.net...

Are the plugs stereo or mono?

In case that was unclear:

Do the plugs have three contacts (tip, ring, sleeve) or just two (tip,
sleeve)?

 

[Pasquale]

Thanks for all your help. Comments below...

Walter Harley wrote:

"Pasquale" <spdrweb@NOTHNXtelusplanet.net> wrote in message
news:kJHBd.42865$KO5.28365@clgrps13...

I have a Universal Microphone with 1/4" jack and the adaptor to 3.5mm.


Sounds like a mono microphone, and could be the kind that doesn't need an
external DC supply voltage. So that's good.

You say "jack". Do you mean "plug"? Jacks are female, plugs are male.

The reference above should have been "1/4 plug" instead of "1/4 jack".
The rest of my references are correct.

Are the plugs stereo or mono?



[The camcorder] has A/V in/out 3.5mm(?) jack. With the camera came a A/V
cable with video, and left and right RCA on one end and the 3.5mm plug on
the other. I am getting the video no problem. As for the audio, I am
getting sound, I just need it to be amplified.


That definitely sounds like a line-level input. So you do need some sort of
microphone preamp. You mentioned you were using a preamp; is it in fact a
microphone preamp? What kind? How are you connecting to it?

The pre-amp... "Permits use of a turntable with a magnetic stereo phono
cartridge with an amplifier not equipped with the appropriate connections."

I know its not meant for what I am trying, but I just need something
temporary. I will get the proper mic pre-amp after the holidays, when
the stores are back to normal hours.

http://www.radioshack.ca/estore/Product.aspx?language=en-CA&catalog=RadioShack&category=Turntable&product=4202111

I am connecting my mic to the adaptor I made and then to the input of
the pre-amp with RCA cable. Then out from the pre-amp to the camcorder
with the A/V cable.

I put together a adaptor cable to go from the 3.5mm microphone jack to the
dual RCA ends. I think it may be from here where I am getting the
static/hum/noise. It seems that if it is held right the noise is pretty
much gone. Maybe poor solder or bad connection to the tail of the
microphone jack (ground).

The way I did the soldering was:

- RCA white inner core wire to the silver tab of the mic jack
- RCA red inner core wire to the copper tab of the mic jack
- copper wire surrounding each are both solder to the tail of the mic jack


It sounds like the "mic jack" you're describing here is the 3.5mm jack into
which you're plugging the mic plug. Or am I confused? If I'm right, it
also sounds like you're describing a stereo 3.5mm jack.

You are correct.

Is the mic plug mono or stereo? If you're plugging a mono plug into a
stereo jack, you will have problems - at the least, one channel will be
missing. So, it sounds to me like you may not have this wired correctly.

The mic plug is mono. The mic jack on my adaptor is stereo. So, I'm just
losing a channel.

I used the link below that was given to me in a earlier response for wiring.
http://www.vandenhul.com/artpap/wiring.htm

But it does also sound like there's a soldering problem.

I'm going to buy another 3.5mm jack for my adaptor and do a better
soldering. Now that I take a closer look at it, it's not so great.
Thinking about, I remember the tabs getting too hot because the tabs
were moving back-and-forth in the plastic core. I'm going to be more
careful this time.

Hopefully that will fix the problem. If not I'll try a repair shop or
Radio Shack and see what they have to say.

Thanks again.

Are you somewhere near a Radio Shack, or a TV repair shop or something?
This sort of problem would take about one minute to diagnose and give you
the right answer, for someone who could actually see what you're talking
about. Trying to do it in text, with inaccurate terminology and incomplete
information, is going to be slow going.