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Amplified Mini Speaker Modifications

mikkut

Jul 8, 2021
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Jul 8, 2021
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Hi All,

I have an analog amplified mini speaker that I would like to make some modifications to:

The amplified mini speaker as is out of the box:
-There is an internal battery that is charged when connected via micro USB . The speaker cannot operate when the battery is charging
-There is a push button on/off switch
-analog audio in is through a 3.5mm male jack (not through USB port)

What I would like to end up with:
-eliminate the battery and have it powered via hard wire to a DC power source (can be a separate wire, does not need to utilize existing micro USB port)
-eliminate the power switch so that is simply on when power is supplied and off when power is disconnected. I tried disconnecting the existing battery and connecting to a DC power supply and the speaker worked fine BUT it still requires turning on the power switch. And when the power is disconnected it appears the power switch re-sets so turning on the power switch is required every time power is connected.

Image attached.INTSUN-CircutBoard-01.jpg
No changes needed on the audio in and audio out.

Thanks!!
 

Martaine2005

May 12, 2015
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May 12, 2015
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Swapping the battery for a DC source is easy as you already tried.
The switch is only momentary. You could try jumping the switch contacts but the unit might just power off.
If you can find the details of the microcontroller, you may be able to power it directly from your DC source.
Somebody posted a similar question a few months ago but I don't recall the outcome.
Try powering the unit while holding the switch to see if the unit comes on.
Martin
 
Last edited:

mikkut

Jul 8, 2021
2
Joined
Jul 8, 2021
Messages
2
Swapping the battery for a DC source is easy as you already tried.
The switch is only momentary. You could try jumping the switch contacts but the unit might just power off.
If you can find the details of the microcontroller, you may be able to power it directly from your DC source.
Somebody posted a similar question a few months ago but I don't recall the outcome.
Try powering the unit while holding the switch to see if the unit comes on.
Martin
holding the switch while powering appears to have no effect ...
 

Martaine2005

May 12, 2015
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That would suggest the microcontroller receives a pulsed signal or pulls it low (grounds it). There may be nothing you can do about it unfortunately.
It might be possible to use a 555 circuit as a 'one shot' device simulating a momentary switch press. But you would need to know more about the circuit you have in order to add to it.
There are a few designers on the forum who may be able to help you.

Martin
 

WHONOES

May 20, 2017
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May 20, 2017
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Can you establish whether the push button switch takes the uP pin high or low.
 
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