Hello.
I have been looking into this over the last few days and its come to my attention that i may have the wrong end of the stick.
I want to make a LED strip flash, dim, strobe and change colour in time with whatever music is playing.
My original idea was to check the output of the amp i am using and put that into the analog pins of the Arduino (this broke the Arduino as i forgot the output voltage was 12v not 5v). I revised the design a bit (with help form the forums) and got a circuit that worked in theory.
Since then after doing a lot more research I think I mis-judged the audio input concept as well as the LED strip control.
Originally i was going to use MOSFETS to control the LED strip but I'm not sure how these fare with PWM over using some standard TIP31 transistors. (please tell me which of these will work and work best please)
Rather than using the RAW output of the amp i looked into using the MSGEQ7 but i lack sufficient knowledge of this and the diagram i drew was based off a breadboard design i found in a video. (see attached)
Can anyone point me in the right direction with this project. Need information on the MSGEQ7 IC and any Arduino code that uses it.
Originally i was going to use MOSFETS to control the LED strip but I'm not sure how these fare with PWM over using some standard TIP31 transistors. (please tell me which of these will work and work best please)
They should both work the same.
If you are using transistors you MUST have base resistors.
You MUST connect the grounds of the two power supplies together.
C4 is way too big it should be 0.1uF not 100uF
Same with C2 and that should be a ceramic capacitor.
In fact you have got most of the components wrong. See the data sheet on page 4 for the recommended values.
Ok rebuilt part of the circuit using mosfets rather than the transistors (used transistors as they were shown in multiple videos and better safe than sorry first time).
Just trying to figure out how i read the DATA_OUT values on the Arduino. Is it through the TX pin or the Digital PWM pins?
Grumpy_Mike:
Still got the circuit of the equaliser wrong. R1 is wrong as is the audio input.
You read the output of the chip with the analogue input of the Arduino.
i took R1 value straight from the data sheet.
Wawa:
This chip is made for <=line level inputs. 100mVpp.
If you connect the output of an amplifier to it, the divider has to be ~1:100.
Use 1k and 100k, and change the 100k later if you have to.
Leo..
I dont understand voltage all the well so can you explain the resistor values. the voltage devider i have set up was to convert the 12v 2a output from the amp down to a manageable ~4.8v. using 1k and 100k only brings it down to about 11.8v if im understanding you correctly.
Later you could replace the 1k resistor for a 10k pot.
Then you can turn up sensitivity if the music is not loud enough to make your LED strip work.
Leo..
The stereo class-D amp that OP is using has four amps in bridge mode.
Two amplifiers for the left channel, and two for right channel.
So each speaker terminal has it's own amplifier.
The amps on the negative terminals are working in the opposite phase.
Twice the voltage on the speaker (4x the power).
Only the positive outs have to be used, and amp GROUND, not speaker negative.
He knows there is mid-supply voltage on the terminal.
Leo..
