I need a little help for a bargraph project

[Modul75]

Hi all and sorry for my bad english,
I am a student and I would like to build a bargraph that would look like something like that :
**broken link removed**

I have heard of the LM3914 and I can find the bargraph itself. Something I don't know is how to make the light work... without noise (the LM3914 needs noise to work, doesn't it?).

I need to make it work with a 3v batterie (CR2032 ) or a standard 9v.

Is there any other component than the LM3914 that would fit better my project?

I have read data about the MM5452 and it seems to work without "load signal", what do you think of this?

Thanks !

 

[MikeMl]

Not clear from your post: What is the input signal? DC level? Audio?

Do you really need 4 independent channels of 15 LEDs each? If so, some sort of uController (PIC?) solution would be better.

 

[Modul75]

Not clear from your post: What is the input signal? DC level? Audio?

Do you really need 4 independent channels of 15 LEDs each? If so, some sort of uController (PIC?) solution would be better.

I would like it to work without noise. I have been advised to use a noise simulator. But this solution is not so easy to me (because of the electrical power necessary).


I don't need 4 independent channels of 15 LEDs each...
can you tell what you think about? thanks again

 

[blueroomelectronics]

Nope still not clear, what sort of noise do you want to avoid? What are the power requirements? as always if you can tell us what it's for...

 

[Mikebits]

Use a microphone with an amplifier. Couple the amp output to a 3914. The mic will detect ambient sounds and noise of a room.

 

[4pyros]

Is it just to flash lights? What do you what, need to display. Thare is 3 types of LM39XX chips, one for audio, one for voltage, and one for LOG audio. LM3914, 15, and 16. Andy

 

[Modul75]

Nope still not clear, what sort of noise do you want to avoid? What are the power requirements? as always if you can tell us what it's for...

Ok I will try to make it clearer (this time) : I wish to create a little device that will work on a 3v battery. This little device will make visual effect thanks to bar graphs. A friend has advised me to use an LM3914. This component is nice but it is supposed to work with a microphone (no light on the bar chart if there is no noise detected by the microphone). Well this is what I have understood from this document :

**broken link removed**

If I need an amp and a mic, then the LM3914 is not suitable for my project as I cannot use a DC adapter.

 

[Modul75]

Nope still not clear, what sort of noise do you want to avoid? What are the power requirements? as always if you can tell us what it's for...

Hi,
I don't wantto avoid noise, I want to avoid the use of an amp and a micro (because of the electrical power necessary)
The power would be (for the whole system) of 3V to 9V
The aim is to make a bargraph that would light on a hazardous cadence.

 

[Modul75]

Is it just to flash lights? What do you what, need to display. Thare is 3 types of LM39XX chips, one for audio, one for voltage, and one for LOG audio. LM3914, 15, and 16. Andy

Yes definitely, it is just to flashlights, like a useless widget lets say...
I don't have any preference between the components LM3914, 15 or 16, I just need something that will do it without a baterie to test and without a micro. (none of these do it as far as I know)

 

[blueroomelectronics]

Your LEDs are going to require far more current than the electronics required to drive them.

 

[Modul75]

Hum... because of the number of bargraphs?
I mean, a single bargraph can work with a 3V baterie, doesn't it?

 

[blueroomelectronics]

Assuming those are LEDs what is their voltage & current rating? Is it for outdoor or indoor use? How large is this sign?

 

[4pyros]

Yes definitely, it is just to flashlights, like a useless widget lets say...

OK do you need the bargraph to go up and down. You could do that with a simple sequncer. a 555 timer and a 4017 counter or do you just whant all the lights to come on at the same time, or flash randomly. Are you trying to make somthing that looks like a working bargraph? Andy