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Need help building a mp3 player with push button volume control.

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So here is the sketch of the idea:

**broken link removed**
the parts:
**broken link removed**
2. KEMO M032 amplifier with 4 wires
M032Beschreibung.JPG


3. mp3 player is BY8001-16P voice module

What i want is to have a push button volume control, because the mp3 player does not have that function when it i sin song triggering mode, so will this work like i draw on the picture or do i need some more components ?
 
Your idea of connecting together everything is wrong because there will be 3 amplifiers.

The Kemo amplifier has such poor quality that its datasheet has no detailed spec's. Its PEAK(?) output is 12WHATS with unknown distortion only when its speaker is 4 ohms and the supply is 16V. With a 12V supply it might produce 2.5Watts RMS continuously into 4 ohms at fairly low distortion. Kemo shows a supply that has positive and negative that is completely wrong. It uses only a positive supply and 0V.
Did you notice that Kemo shows 5 wires but you wrongly show only 4 wires?

The Chinese MP3 player has two speaker output wires. There is not enough information to see if you must not short an active output to ground like you are doing with the TDA8551 amplifier and if a coupling capacitor is needed. Its output level is probably much too high to feed an amplifier since it already has an amplifier.

The TDA8551 amplifier with digital volume control has two active outputs but you are shorting one of them to 0V at the input of the Kemo amplifier.
 
you'll wear out your finger and the switch going thru 64 steps.. Dont you want to add a tertiary clock 15Hz?

-5V should read 0V.
 
the mp3 module has an output for external amplifier:
**broken link removed**
And i am using that output the DACL pin with 10uf capacitor, and the ground, as for the amplifier it rely has 4 wires as shown on the picture. This is model m032 that has 4 wires, the model m032N has 5 wires.
The speaker will be an siren speaker with 8 or 16 ohm. so i don't need stereo only mono.
So what i don't know how to do is connect this mp3 module with the volume control chip, so a schematics would be helpful , and is there any way to use this amplifier or i most search for another one ?
 
It is pointless to use the volume control chip without a lot of extra circuit.
...debounce and tertiary clock outputs with mute on power up and then waste the 1W power amp included.
.. cant you control volume of recorded signal and trim an attenuator?

You wont get much power with 16 Ohms on 12V
 
I must use a push button volume control, because it will be controlled by remote relays. and the power is not the point here, this is not for music this is for animal sound. so sometimes i need it loud and sometimes quiet.

Or if somebody have a better solution for push button volume control please share.

I think the best solution is an amplifier module with integrated push button volume control, but i did not find nothing like that.
 
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You show two 10uF coupling capacitors SHORTING TOGETHER the left channel output and the right channel output of the MP3 player that might destroy it. Use only one output.
You are shorting the signal output pin 5 of the TDA8551 to ground on the Kemo amplifier that will probably destroy the TDA8551.
 
OK, i have chose another amplifier for this project, this one:
**broken link removed**
is this amplifier a good idea for a siren speaker ??

and for the volume control i am now searching for an mp3 module that has these functions:
- song triggering up to 10 songs
- read from USB or SD or microSD memory cards, or integrated memory 128Mb minimum
- volume control with key triggering (grounding)
- the price should be less then 20$ because i will be making this more than 10 devices.

So if anyone finds a good mp3 module please tell me.
 
Again, cheap ebay junk has no detailed spec's. It says the TDA2030A amplifier can be powered from 6V to 12V but the datasheet for the TDA2030A has its output power rated with 24V as its minimum supply voltage when its output into 8 ohms is 6W. Its output with a 12V supply will be about 1.2W.
 
I solved my problem using a new mp3 module that has volume control and 3 songs ground triggering functions, and gives out a nice clear sound, the cheap ebay amplifier does get hot, but i will put on a bigger heatsink.
Now i have a question about charging a 12v sealed lead acid battery 2.2Ah, on the battery there is a charging instruction:
**broken link removed**

And i will be using a battery charge idicator: **broken link removed**
with 4 leds showing 20%, 50%, 80%, 100%

So the question is whats the best charge level in percents for charging this battery if i want to have a long lifetime of the battery?
and can i charge it with this charger?
https://www.ebay.de/itm/Steckernetz...er-LED-5679-/271067543006?hash=item3f1ce275de
it has output 500ma stabilized.
 
Again, ebay junk has no detailed spec's.
1) The battery charge indicator does not say the chemistry of the battery (lead-acid, Ni-Cad or Lithium) and does not say if its indicated voltages are with how much load or with no load and an unlisted resting time.
2) The "charger" looks like a simple power supply, not a battery charger circuit for a lead-acid battery and is written in a foreign language.
3) The battery label does not say if the "initial current" must be limited by the battery charger circuit. It also does not say the low voltage when the load should be disconnected (it is probably not "deep discharge").

The TDA2030A amplifier IC should not get hot when powered from only 12V. Its datasheet shows that it barely works when its supply is as low as 12V. Its spec's are with a 32V supply where the output power and heating are almost 10 times higher. Maybe the pcb is designed wrong causing it to oscillate at a high frequency that quickly drains the battery and makes heat.
 
Here is the **broken link removed** of the battery, ? the power supply that i have linked before is in German language, and it says that the current is 500ma limited, and yes it is a simple power supply, without battery charger circuit, but will the battery charge with only 12v and current limit ?
 
The label on the front of the battery and the spec's show that the 12V power supply will not charge the battery because its voltage is too low.
 
I have finally found a suitable charger AL-300-pro. And now i have one last question:

- If the battery is used ones or twice a week for 1h with ~300ma of load, for the long battery lifetime what is approximately the best discharge level of the battery in percents when i should charge it ?
 
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The AL-300-pro charger is fine but it will take all day or all night charge your battery.
The TDA2030A amplifier produces a maximum output of 1.2W RMS into an 8 ohms speaker when the battery is 12V or a little more when the battery is 13V. If the speaker is 4 ohms then the power will be about 2W. The idle current is 50mA when the supply is 32V but who knows how much it will drop when the supply is only 12V or 13V? Maybe it will be 40mA.

When the amplifier is producing 1.2W then it heats with about 0.6W for a total of 1.8W. Or producing 2W and heating with 1W for a total of 3W.
1.8W/13V= 139mA + 40mA= 179mA from the battery when playing at full blast continuously into 8 ohms. Or 3W/13V= 231mA + 40mA= 271mA from the battery when playing at full blast continuously into 4 ohms.
But nobody plays music at full blast, music has dynamic levels and averages much less. So your battery discharge current will be maybe 70mA for an 8 ohm speaker or 90mA for a 4 ohm speaker.

The battery has a capacity of 2.2Ah when discharged to 10.5V.
At these currents a battery charge will last for 2200mA/70mA= 31.4 hours with an 8 ohm speaker or last for 2200mA/90mA= 24.4 hours with a 4 ohm speaker. If the amplifier is not playing then a battery charge will last for 2200mA/40mA= 55 hours.

The battery is allowed to be discharged very low. Its spec's say it will produce more than 500 charge-discharges or last for 3 to 5 years which ever occurs first.
 
That sounds great, now i have all that i need, and i have found a nice battery indicator for lead acid battery: **broken link removed**
Thanks for all the help.
 
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