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Plz Help me playing with these leds

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na501

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Im a newbie to electronics but a geek to this field. I want to make something to my baby: some leds which can sync to music playing on my pc or my phone via 3.5 audio jack. I googled and found some easy plans which are claimed to work, however there are still a lot of opposite ideas which confused me :confused:. Then I happened to see this forum and see a lot of pros :). So could you please advise me on this schema which is found on inforbarrel.com. Is it good enough? And if there are some things wrong could you please revise it for me in the simplest way so that I can understand and can follow (not like a maze of line and electric symbols :confused:).
Here is the part list:
6 LED's of the same color. If you're a beginner you'll probably need more because you will burn them out. ($1.50)
A transistor, this will amplify the signals sent from your iPod. There are many kinds almost any will work. ($2.00)
A resistor, more if you are a beginner. Anywhere from 375 to 425 Ohms will be fine.($0.50)
Some electrical wire.
3 AA batteries you may need more if you are using high voltage LED's.
1 pair of headphones that you can destroy.

and the schema:
**broken link removed**
**broken link removed**

Thank you in advance.
 
Im a newbie to electronics but a geek to this field. I want to make something to my baby: some leds which can sync to music playing on my pc or my phone via 3.5 audio jack. I googled and found some easy plans which are claimed to work, however there are still a lot of opposite ideas which confused me :confused:. Then I happened to see this forum and see a lot of pros :). So could you please advise me on this schema which is found on inforbarrel.com. Is it good enough? And if there are some things wrong could you please revise it for me in the simplest way so that I can understand and can follow (not like a maze of line and electric symbols :confused:).
Here is the part list:

Thank you in advance.

hi,
Dont make it as shown in your drawing, it will not work.:)

Where did the 'design' come from.?
 
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hi,
Dont make it as shown in your drawing, it will not work.:)

Where did the 'design' come from.?

You can search in **broken link removed** with key words "leds dance to music".
So how can I have a working schema with the same idea? What do I have to modify this plan?
 
What do you want to do?

Flash an LED when music plays?

Each LED needs a series resistor to limit the current.

The transistor needs a base resistor wired in series, not parallel as per the drawing you've posted, to limit the current in to the base.

There are plenty of tutorials and reference guides to confusing electronic symbols, more confusingly the pin-out of transistors vary so you should check the datasheet which can normally be found by typing the part number into Google.

Here's a simple idea which will work. It's designed for 12V operation but it's fairly easy to change the design so it works from a couple of AA batteries. It should also work as-is from a 9V battery.

**broken link removed**
 
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Here's a more nube friendly version of the schematic posted above.
 

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You show a transistor on your side of the world (BCxxx).
The pins layout are different on my side of the world (2Nxxxx).
 
That's the problem with pictures, they may be nube friendly but they don't account for different pin-outs.

I did say it was the BC548 but the original poster might substitute it with a backwards transistor and it won't work.
 
Thanks for your great help. I'll try your schema and feed back asap
 
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Here's a more nube friendly version of the schematic posted above.
My friend, i have tried your plan but it didnt work. The leds were lit but there is no sync with playing music at all. Could u review and help me out again. Thank u!
 
The extremely simple circuit will light the lEDs continuously if the music source has a positive DC on it. Use a 10uF coupling capacitor.
It is shown with a BCxxx European transistor. Turn around a 2Nxxxx american transistor.
 
How many small battery powered headphone amplifiers do you know of are DC coupled?

It's possible that the circuit has been connected incorrectly.

Maybe the collector and emitter connections have been reversed?

Anyway try this and if it doesn't work reverse the transistor connections.

Look at both the real schematic and the picture, it will help you understand how to connect components up so next time you won't need a picture; the schematic will do.

Look at the datasheet for the transistor you're using; this can normally be found by Googling for the part number which is written on it. The datasheet will tell you what eash pin on the transistor connects to .
 

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How many small battery powered headphone amplifiers do you know of are DC coupled?
I was thinking of the circuit shown on the datasheet of the TDA2822M stereo amplifier IC made by ST Micro or SGS-Thomson or whatever they are called today. Their photo-copier or scanner is horrible.
 

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So the returns from each transducer are connected to 0V via a single capacitor, have I got that right?

There shouldn't be much DC because the amplifier are on the same IC so should be pretty well matched.

I can't believe you didn't spot my deliberate mistake. ;) I got the resistor colour codes wrong. The 1k resistor is drawn as 2k11.

I should've also used four band codes for 5% tolerance resistors. Five band is never used on 5% because it it specifies too many digits for such a wide tolerance.

I've corrected the drawing.
 

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The TDA2822M stereo audio amplifier has outputs that are at half its supply voltage so it might turn on the LEDs continuously which is the problem experienced by the OP. Maybe his audio player is the same and needs a coupling capacitor to feed the transistor that drives the LEDs.

I ignored your 1% resistor values but now I notice that you made a 440 ohm resistor.
 
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It's 330R, orange, orange, brown.

Perhaps the orange looks too yellowish?

I've changed that, not it's definitely orange, not orangish yellow.
 

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I have seen Chinese resistors where many colours look the same.
 

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When compared side by side I'd obviously say the bottom one is 330R.

But when you compare it to a 440R resistor, it's obvious it's 330R.

I wouldn't make the mistake anyway, because I'd realise that 440 isn't a standard E24 value so I'd know it's supposed to be 330.

If it was a 0.1% tolerance resistor then it's more likely to cause confusion but I'd check the list of E192 values if it's in a circuit or reach for my DVM if it's not connected to anything.
 

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Ok I have managed to complete my project.
And here are the schema: (I googled)

**broken link removed**

I have modified to this schema to a group of 9 red leds (in parallel with power source of 9 DC) synchronizing to playing music. And It works for me.

However there is one small problem: my project only sync to music played on my computer but not on my mobile phone (Nokia N86).

Could you help me to make it sync with music played on my mobile phone also?
 
Ok I have managed to complete my project.
And here are the schema: (I googled)

**broken link removed**

I have modified to this schema to a group of 9 red leds (in parallel with power source of 9 DC) synchronizing to playing music. And It works for me.

However there is one small problem: my project only sync to music played on my computer but not on my mobile phone (Nokia N86).

Could you help me to make it sync with music played on my mobile phone also?

Your transistors are missing a part number.
Why use two transistors when only one transistor is needed?

The base-emitter junction of the transistor will short-circuit your music source because the base is missing a series current-limiting resistor. Then your music source might burn out.
If the music source plays loud then the emitter-base might be damaged by a reverse voltage too high because a protection diode is missing.

One transistor needs an input of 0.7V to turn on. Your phone might not have a signal level that is high enough.

Your LEDs are connected in series. Your first drawing showed them wrongly in parallel.
 
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