Urgent - LED bar meter - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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
Reply
 
Thread Tools Search this Thread
Old 27th August 2015, 02:03 AM   #1
diyAudio Member
 
Join Date: Aug 2011
Location: Canada
Default Urgent - LED bar meter

Hello Everyone!

I am doing a rebuild on my amplifier, and I would now like to add on two 5 inch LED bar meters to it. I am not too skilled in the digital side of things but all input is HIGHLY appreciated, more over to simple analouge. The amps is a very simple power amps with no VI protection. I may throw a speaker protector on it later.

I just need a circuit to drive these 50 red LED's!

The amp is 22 inches wide so two 5 inch meters leave just around 3 equal 5 inch spaces in the face, not including a power LED.

Thanks many in advance, GamerAndds!

Part 2 of my amp- https://www.youtube.com/watch?v=9KgotLiD3So
  Reply With Quote
Old 27th August 2015, 02:41 AM   #2
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Location: Upper midwest
Quote:
Originally Posted by Gamerandds View Post
I just need a circuit to drive these 50 red LED's!
Here's a start.
Mini LED Volume Towers (VU meters)
  Reply With Quote
Old 27th August 2015, 02:56 AM   #3
diyAudio Member
 
Join Date: Aug 2011
Location: Canada
Those use the LM3914/15/16 series ic, most of those ic's cannot do over 30 LEDs... Unless someone has a way to use 5 ic's with the 39xx series... The voltage swing of the output is +/- 60 volts... I would at least like to be able to tune it for +/- 70 volts... A simple resistor veidge will do this but... Help! I need to run 50 led, 5 bar meter segments- total of 5 inches!
  Reply With Quote
Old 27th August 2015, 04:18 AM   #4
diyAudio Member
 
Join Date: Aug 2011
Location: Canada
I would also like the option to switch it from dot to bar, but I want it in dot mode if I cant get it to be switchable.
  Reply With Quote
Old 27th August 2015, 05:38 AM   #5
diyAudio Member
 
Join Date: Apr 2010
Location: Coffs Harbour
LM3914 series can be expanded from 20-100 steps according to the datasheet app. notes.
The voltage to be measured can be scaled by resistive dividers to any range you like - even transformer isolated if necessary. LM3914 MDC ... - Datasheet Search Engine Download

If you want every imaginable wizbang feature possible in a bargraph display, then you may have to think about developing your own multiplexed Microprocessor design and software. Then it's way out of the scope of an Audio power amplifier forum and into the everything else forum here or another group devoted to Microprocessors entirely.
__________________
Ian
  Reply With Quote
Old 27th August 2015, 02:05 PM   #6
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
I'm surprised no one has a DIY kit to do the PL Series 2 type LED display. That's probably where the OP is going with this. I'm sure the original driver ICs are NLA - back in my college days I built one using 5 3914's and a 555 timer to do the full scale indicator. It does work and it's not that hard. Looked d*mn convincing in the dark - once I got the hold times correct on the peak detector and the flashing set of 4 on the end. I ended up re-purposing the 3914's to drive banks of colored PAR38 floods, as I needed those more at the time.
  Reply With Quote
Old 27th August 2015, 02:27 PM   #7
diyAudio Member
 
Join Date: Nov 2008
Check (almost a pun) this out: www.s-o.webnode.cz/vu-meter/ E
  Reply With Quote
Old 27th August 2015, 09:56 PM   #8
Ripcord is offline Ripcord  United States
diyAudio Member
 
Ripcord's Avatar
 
Join Date: Sep 2013
Location: Kodak, TN.
One more idea.

DIYfan: LED VU Meter with LM3916
  Reply With Quote
Old 27th August 2015, 10:10 PM   #9
diyAudio Member
 
Join Date: Aug 2011
Location: Canada
Quote:
Originally Posted by wg_ski View Post
I'm surprised no one has a DIY kit to do the PL Series 2 type LED display. That's probably where the OP is going with this. I'm sure the original driver ICs are NLA - back in my college days I built one using 5 3914's and a 555 timer to do the full scale indicator. It does work and it's not that hard. Looked d*mn convincing in the dark - once I got the hold times correct on the peak detector and the flashing set of 4 on the end. I ended up re-purposing the 3914's to drive banks of colored PAR38 floods, as I needed those more at the time.
Thank you Ian, that does not seem to be the case with the 15/16 though? Can use 5 together, is it possible?

Thank you to my fellow canadian aswell, Micky Moose! I will get a closer look at it. The digital scares me but I will have to look into it!
Thanks aswell to Ripcord!

Thank you WG_SKI!! Those PL ones are wicked- my dad tells me all the time about them but their UAA170's chips are "NLA" as you said above- with great sadness! I was thinking about using some diodes with the LM39XX series to get a "back trace" and a cap to slow it down... but still thats 50 diodes and resistors per side!

You are pefectly correct, the phase linear 400, 700 and 500 is what im going for!

Now how to do it for 50 all driven.... in the circuit only 36 is driven and the last 4 just come on- which isnt bad but... I want 50 All Driven!! Muhaha

Last edited by Gamerandds; 27th August 2015 at 10:17 PM.
  Reply With Quote
Old 28th August 2015, 12:57 AM   #10
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
The biggest problem with getting 50 of them going is the signal getting noisy giving false readings. The low end of the scale is VERY low, and proper star grounding must be used for the signal and for the references for the dividers. The data sheet shows you what to do. Run things off a relatively high voltage, set the reference dividers to let full scale be say, 14 volts, and use op amps to amplify the signal ahead of the low range 3914's. The full data sheet (from the original paper bound data book) outlines the theory of operation. Read it, understand it, and work with one or two on a breadboard until you understand it fully. Then embark on the 50-element meter project.

I wish I still had time to play with this stuff. It was fun.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
A LED meter, Volt meter, power meter or light indicator... a nice gadget destroyer X Solid State 5 25th February 2011 06:30 PM
LED VU meter using existing bar graph Preamp Analog Line Level 4 13th January 2011 01:54 PM
Where do i find an LED Bar? guitarguy12387 Parts 6 7th July 2008 01:07 PM
AN6882 bar graph LED drivers: what instead? Wavebourn Solid State 9 30th June 2008 08:34 PM
LED VU meter neil_kaye Parts 8 27th December 2006 07:43 AM


New To Site? Need Help?

All times are GMT. The time now is 03:45 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2