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Newbie projects

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tntero

New Member
Hi there people, im kinda new to electronics and i wnated to know some basic but cool projects, like for example the ''sound reactive'' LED's, i like a good lightshow, so if you could help me out with some light/LED projects i would be thankfull

P.S.: Here's the link for the sound reactive LED's project, its a mod for a PSP but i used it in computer speakers and it works pretty neat.
 
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KMoffett

Well-Known Member
Google: color organ

Ken
 

tntero

New Member
Google: color organ

Ken
Cool one, i would be thankfull if you got me a schematic, i saw a guy on Utube who did one with rgb led, somthing like red for high tone,blue for low and green for mid tones, i might have the colours wrong though
 

KMoffett

Well-Known Member
tntero,

Did you Google color organ? There are tons of schematics out there. If you want the use LEDs, Google: LED color organ

Ken
 
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Number17

New Member
also can you think of any other project that is fairly easy and fun or cool too?
It depends on what type of project is fun for you. At the moment I spend a little time each night to make a small rc car. To make rc stuff is fun for me, but probably not for you. Point is, it is difficult to suggest a intersting project if you don't specify what type of project you want to do.
 

KMoffett

Well-Known Member
also can you think of any other project that is fairly easy and fun or cool too?
Fairly easy for me and fun and cool for you? I know about me...I need more info about what you find cool! ;)

Ken
 

tntero

New Member
well, im fascinated by lightshows and stuff like that,i would also like to try some project using a 555 timer just to understand how it works, also, any ideias on how to create an IR sender and a receiver to turn on and off a light?
 

audioguru

Well-Known Member
Most Helpful Member
The "sound reactive LEDs project" has the transistor connected upside-down because the author has the rounded side and the flat side of the TO-92 case mixed up and the transistor is connected like a PNP type but it is an NPN type.

Both wrong connections make it correct, excepy nothing limits the base current and nothing limits the LED current.
 

tntero

New Member
The "sound reactive LEDs project" has the transistor connected upside-down because the author has the rounded side and the flat side of the TO-92 case mixed up and the transistor is connected like a PNP type but it is an NPN type.

Both wrong connections make it correct, excepy nothing limits the base current and nothing limits the LED current.
well right or wrong, i connected that way and it works just fine, btw, i used 2 LED's in series for eache transistor, do you think it would be more sensitive if i used 1 transistor to each LED?
by more sensitive i mean, would it light up with less volume?
 

audioguru

Well-Known Member
Most Helpful Member
Without limiting the base current of the transistor with a resistor then the sound source (MP3 player?) and the transistor might burn out.
Without limiting the LED current with a resistor then the LED and the transistor might burn out.

Two LEDs being driven in series need an 8V power supply. One LED needs a 4V power supply. You have a 2V to 3V battery as a power supply so two LEDs in series will be dead.
 
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tntero

New Member
Without limiting the base current of the transistor with a resistor then the sound source (MP3 player?) and the transistor might burn out.
Without limiting the LED current with a resistor then the LED and the transistor might burn out.

Two LEDs being driven in series need an 8V power supply. One LED needs a 4V power supply. You have a 2V to 3V battery as a power supply so two LEDs in series will be dead.
actualy, the speakers are in a computer, and the source power is 9V, so it works just fine, and i actually have it done, why are you doubting that much? i was telling how i did, not how i was going to do OK?
 

audioguru

Well-Known Member
Most Helpful Member
why are you doubting that much? i was telling how i did, not how i was going to do OK?
It is WRONG without having a resistor to limit the base current of the transistor and without having another resistor to limit the LED current.

The article shows the emitter connected to the LED but the article is also WRONG. The Collector of the transistor connects to the LED.
 

audioguru

Well-Known Member
Most Helpful Member
DUDE, your VU meter its pretty cool, how can i do one of those?, i mean do you have a schematic or something?
There are hundreds of VU meter projects on the internet. All use the LM3015 LED bar graph driver IC. The datasheet of the LM3915 shows the schematic of an extremely simple VU meter.
 

tntero

New Member
There are hundreds of VU meter projects on the internet. All use the LM3015 LED bar graph driver IC. The datasheet of the LM3915 shows the schematic of an extremely simple VU meter.
thanks, and BTW, its good to talk to you without being arguing, and about the speakers, it works...I know it has got an higher voltage than reccomended, but because it is only 1 volt it works fine, when the LED's fry, i'll buy some new ones
 

Luminax

New Member
the basic of VU meter is voltage driven detector driving a multi-stage voltage detector which in turn drives a switch-style LED signal driver. Mostly there are ICs for that which detects voltage(equals to sound/music amplitude mostly) and reacts accordingly(lighting up the appropriate level of LEDs).
For tone-based ones you might want to hook different tone-filter stages in-between the audio output and the voltage detector stage, so each bass/middle/treble range have its own set of VU meter.
 
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