LED VU meter

neil_kaye · 21st December 2006, 06:05 PM

LED VU meter for ZV9
I would like to build an LED VU meter to measure the DC offset for each channel.
I imagine there to be 5 or 6 LEDS where 1 would glow for lowest output whilst 5 would glow at max.
I just finsihed populating my ZV9 boards and thought this might be an interesting way to use the iconic Pass Blue LED.
Please help and newbie figure this out.
Thanks for your time
Neil

neutron7 · 22nd December 2006, 05:06 AM

all you need is the LM3915 dot/bar driver from national. very easy to use!

AndrewT · 22nd December 2006, 04:06 PM

Hi,
a novel use for a bargraph.
Now which should you choose? lin, log or VU?

DC output offset monitoring with a couple of reds, a couple of orange and the other 5 for green to confirm that all is OK, probably best in dot mode.
The top limit could even overflow to turn off the output relay.

cpemma · 25th December 2006, 09:07 PM

The basic LM391x has a range of 1.25V, you can extend that down a bit but for usual offset voltage magnitudes you'll need a voltage amplifier stage. Measuring both positive and negative offset levels also adds to the complexity, but an opamp amplifier with virtual earth set to mid-range on the bargraph may solve that.

However,

Quote:

I would like to build an LED VU meter to measure the DC offset for each channel...I imagine there to be 5 or 6 LEDS where 1 would glow for lowest output whilst 5 would glow at max.

Do you mean "DC offset" in the conventional sense of setting up an amplifier, or do you want an indication of the magnitude of the speaker voltage when music's coming out? That's a different kettle of fish, much easier. See LM3915/LM3916 datasheets.

neil_kaye · 26th December 2006, 02:30 AM

Thanks for the response. I guess i meant magnitude of speaker voltage

theAnonymous1 · 26th December 2006, 05:02 AM

Quote:

Originally posted by neil_kaye
Thanks for the response. I guess i meant magnitude of speaker voltage

Awww, I think you actually sparked some interest in the fact people thought you wanted to measure and display the DC offset voltage and not just the output level.

AndrewT · 26th December 2006, 08:53 AM

Yes,
green, orange, red, shut down (with latch) on DC output offset was a much more interesting project!

neil_kaye · 26th December 2006, 03:29 PM

ughhh, i am just a beginner... making htis up as i go along.
A year ago i didn't know how to hold a soldering iron.
Turns out with a little help of google there a about 100 simple circuits doing exactly what i want.
Perhaps for the next project i might attemopt DC offset... first go to figure out what it is though

DJ Exprice · 27th December 2006, 07:43 AM

I got some boards made for a VU meter a little while ago.

Zipped Eagle Files:

21st December 2006, 06:05 PM	#1
neil_kaye diyAudio Member Join Date: Dec 2005 Location: San Francisco	LED VU meter LED VU meter for ZV9 I would like to build an LED VU meter to measure the DC offset for each channel. I imagine there to be 5 or 6 LEDS where 1 would glow for lowest output whilst 5 would glow at max. I just finsihed populating my ZV9 boards and thought this might be an interesting way to use the iconic Pass Blue LED. Please help and newbie figure this out. Thanks for your time Neil

22nd December 2006, 04:06 PM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, a novel use for a bargraph. Now which should you choose? lin, log or VU? DC output offset monitoring with a couple of reds, a couple of orange and the other 5 for green to confirm that all is OK, probably best in dot mode. The top limit could even overflow to turn off the output relay. __________________ regards Andrew T.

26th December 2006, 08:53 AM	#7
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Yes, green, orange, red, shut down (with latch) on DC output offset was a much more interesting project! __________________ regards Andrew T.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
car RPM meter 2	ido2	Everything Else	2	11th September 2007 08:36 AM
how to make this esr meter work with 250uA Panel meter	dytln_02	Everything Else	2	27th January 2007 10:13 PM
inductance meter from a cheap meter?	jarthel	Parts	3	22nd September 2006 05:37 AM
Making a milliAmp meter, become a Volt meter	redrabbit	Power Supplies	11	26th May 2006 07:51 PM
t-amp vu meter and volt meter question....	rectaacies	Class D	7	3rd February 2006 11:22 AM


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

22nd December 2006, 05:06 AM	#2
neutron7 diyAudio Member Join Date: Dec 2003 Location: Toronto Canada	all you need is the LM3915 dot/bar driver from national. very easy to use!

26th December 2006, 02:30 AM	#5
neil_kaye diyAudio Member Join Date: Dec 2005 Location: San Francisco	Thanks for the response. I guess i meant magnitude of speaker voltage

26th December 2006, 03:29 PM	#8
neil_kaye diyAudio Member Join Date: Dec 2005 Location: San Francisco	ughhh, i am just a beginner... making htis up as i go along. A year ago i didn't know how to hold a soldering iron. Turns out with a little help of google there a about 100 simple circuits doing exactly what i want. Perhaps for the next project i might attemopt DC offset... first go to figure out what it is though

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read