"jbclem" wrote in message
...

I'm looking for a supplier that sells a small red led gauge(3 or 4 led)
that I will use
to read voltage coming from the oxygen sensor in my car. The guage
pictured below is
accurate to .001 volt, runs off of 8-15volts. The voltage output from the
oxygen sensor
is usually between .1 volt and 1.00 volt, and changes rapidly). The red
LEDs are bright
enough to read in sunlight, so it can be mounted on my dashboard.

I don't know much about electronics so I'm not sure what kind of circuit
is used to make
such a readout work. I'd appreciate any ideas or suggestions about this.
Why don't I
buy the one pictured? Well, at $69.00 + $9.95 shipping, it seems a bit
high. I'm
thinking more in the $5-10 range.

Buy a DMM for less than $10. Or

http://www.allelectronics.com/cgi-bi...122&type=store

http://www.allelectronics.com/cgi-bi...200&type=store

N

"jbclem" wrote in message
...
I'm looking for a supplier that sells a small red led gauge(3 or 4 led)
that I will use
to read voltage coming from the oxygen sensor in my car. The guage
pictured below is
accurate to .001 volt, runs off of 8-15volts. The voltage output from the
oxygen sensor
is usually between .1 volt and 1.00 volt, and changes rapidly). The red
LEDs are bright
enough to read in sunlight, so it can be mounted on my dashboard.

I don't know much about electronics so I'm not sure what kind of circuit
is used to make
such a readout work. I'd appreciate any ideas or suggestions about this.
Why don't I
buy the one pictured? Well, at $69.00 + $9.95 shipping, it seems a bit
high. I'm
thinking more in the $5-10 range.

John



If you don't know much about electronics you won't save much money trying to
make one.

There is something about that: you can't measure the output of an O2 or
Lambda sensor with a standard DVM.

I have also heard that you can damage one trying to measure it with a
DVM. I don't know if I buy this, except maybe if the loading during the
warmup stage screws it up. Far fetched I think.

I do know this, you don't really get any kind of meaningful reading on
a DVM from an O2 sensor.

JURB

wrote in message
oups.com...
There is something about that: you can't measure the output of an O2 or
Lambda sensor with a standard DVM.

I have also heard that you can damage one trying to measure it with a
DVM. I don't know if I buy this, except maybe if the loading during the
warmup stage screws it up. Far fetched I think.

I do know this, you don't really get any kind of meaningful reading on
a DVM from an O2 sensor.

JURB


You need a really high impedance meter, and very short or well shielded wire
runs. The O2 sensor has a very high impedance output and is easily
interfered with.

Funny you should say this...I've made this measurement a number of times using my
Wavetec DVOM. I just wanted a permanent fixture that I could have somewhere on my dash.
The panel gauge pictured in my message was being sold for that precise purpose,
measuring the Lambda sensor output...I'm just trying to duplicate it without spending
alot of money. Today I ran a wire from the engine compartment O2 sensor wire to the
front of the car (VW Vanagon) and drove around with the DVOM hooked up to the wire and
was getting readings that were consistent with open loop and closed loop status.

I looked in AllElectronics and some other sites, they have LED panel meters but so far
none with .001 resolution and none that operate with 9-14 volts. I'm also not sure what
kind of circuit(board) is needed to use these panel meters as a voltmeter. On the
other hand buying a cheap DMM might be a solution if Il could find one that used LEDs
and read millivolts. Is there such a thing?

John





wrote in message
oups.com...
There is something about that: you can't measure the output of an O2 or
Lambda sensor with a standard DVM.

I have also heard that you can damage one trying to measure it with a
DVM. I don't know if I buy this, except maybe if the loading during the
warmup stage screws it up. Far fetched I think.

I do know this, you don't really get any kind of meaningful reading on
a DVM from an O2 sensor.

JURB

"jbclem" wrote in message
...

On the
other hand buying a cheap DMM might be a solution if I could find one that
used LEDs
and read millivolts. Is there such a thing?

No, they're all LCD these days and have been for years.

http://www.allelectronics.com/cgi-bi...122&type=store

3.5 DIGIT LED PANEL METER, 200 MV

Maximum Input: 199.9mV DC

Supply Voltage: 5Vdc (Zener off battery should work)

Common Ground - Can monitor own voltage - very important for this
application.

Your Price: $15.00 each

N

NSM wrote:

"jbclem" wrote in message
...

On the
other hand buying a cheap DMM might be a solution if I could find one that
used LEDs
and read millivolts. Is there such a thing?

No, they're all LCD these days and have been for years.

http://www.allelectronics.com/cgi-bi...122&type=store

3.5 DIGIT LED PANEL METER, 200 MV

Maximum Input: 199.9mV DC

Supply Voltage: 5Vdc (Zener off battery should work)

Common Ground - Can monitor own voltage - very important for this
application.

Your Price: $15.00 each

N

What I'd like to see is a DPM with a fast pointer like
the Fluke '87-88 series of meters and high-impedence mV
readings to 0.001 resolution. Averaging would be nice, too.

JazzMan
--
************************************************** ********
Please reply to jsavage"at"airmail.net.
Curse those darned bulk e-mailers!
************************************************** ********
"Rats and roaches live by competition under the laws of
supply and demand. It is the privilege of human beings to
live under the laws of justice and mercy." - Wendell Berry
************************************************** ********

JazzMan wrote:
NSM wrote:

"jbclem" wrote in message
...


On the
other hand buying a cheap DMM might be a solution if I could find one that

used LEDs

and read millivolts. Is there such a thing?

No, they're all LCD these days and have been for years.

http://www.allelectronics.com/cgi-bi...122&type=store

3.5 DIGIT LED PANEL METER, 200 MV

Maximum Input: 199.9mV DC

Supply Voltage: 5Vdc (Zener off battery should work)

Common Ground - Can monitor own voltage - very important for this
application.

Your Price: $15.00 each

N


What I'd like to see is a DPM with a fast pointer like
the Fluke '87-88 series of meters and high-impedence mV
readings to 0.001 resolution. Averaging would be nice, too.

JazzMan


Hi...

I'd give my right arm for a meter that incorporated both
a digital readout and a very lightly damped moving pointer...

Kinda like those wrist watches that have both hands and
a digital readout at the bottom.

Take care.

Ken

On 17 Jun 2005 21:47:01 -0700, put finger to keyboard
and composed:

There is something about that: you can't measure the output of an O2 or
Lambda sensor with a standard DVM.

I have also heard that you can damage one trying to measure it with a
DVM. I don't know if I buy this, except maybe if the loading during the
warmup stage screws it up. Far fetched I think.

No, it's true. Measuring its voltage with a standard high impedance
DMM is perfectly OK, but trying to measure its resistance will inject
a current into it. This current may damage the sensor.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

I'm looking for a supplier that sells a small red led gauge(3 or 4
led) that I will use to read voltage coming from the oxygen sensor in
my car. The guage pictured below is accurate to .001 volt, runs off
of 8-15volts. The voltage output from the oxygen sensor is usually
between .1 volt and 1.00 volt, and changes rapidly). The red LEDs are
bright enough to read in sunlight, so it can be mounted on my
dashboard.

I don't know much about electronics so I'm not sure what kind of
circuit is used to make such a readout work. I'd appreciate any ideas
or suggestions about this. Why don't I buy the one pictured? Well, at
$69.00 + $9.95 shipping, it seems a bit high. I'm thinking more in the
$5-10 range.

My thoughts would be along the lines of using an LED VU meter originally
designed to measure sound levels. With an instrument grade OP amp on the
front end to provide a high impedance input. And probably some mods to
make the input to the VU device DC coupled.

But you'd not do this for near $10

--
*The early bird gets the worm, but the second mouse gets the cheese *

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
I'm looking for a supplier that sells a small red led gauge(3 or 4
led) that I will use to read voltage coming from the oxygen sensor in
my car. The guage pictured below is accurate to .001 volt, runs off
of 8-15volts. The voltage output from the oxygen sensor is usually
between .1 volt and 1.00 volt, and changes rapidly). The red LEDs are
bright enough to read in sunlight, so it can be mounted on my
dashboard.

I don't know much about electronics so I'm not sure what kind of
circuit is used to make such a readout work. I'd appreciate any ideas
or suggestions about this. Why don't I buy the one pictured? Well, at
$69.00 + $9.95 shipping, it seems a bit high. I'm thinking more in the
$5-10 range.

My thoughts would be along the lines of using an LED VU meter originally
designed to measure sound levels. With an instrument grade OP amp on the
front end to provide a high impedance input. And probably some mods to
make the input to the VU device DC coupled.

But you'd not do this for near $10


You could with some salvaging or utilizing free samples from semiconductor
companies but not without some electronics knowledge or at least a fair
amount of reading up on stuff.