Maker Pro
Maker Pro

Amplifier the smartphone headphone port voltage

Yasas Weerasinghe

Nov 20, 2018
4
Joined
Nov 20, 2018
Messages
4
My phone doesn’t have IR feature, so I create a IR blast and to increase the working distance I need more power to IR LEDs.

So is it possible to increase the headphone port power?

If it’s how?

Thankyou!
 

Audioguru

Sep 24, 2016
3,656
Joined
Sep 24, 2016
Messages
3,656
Feed the headphones output from the phone into the input of a more powerful amplifier. Then the IR LEDs might be destroyed.
 

Yasas Weerasinghe

Nov 20, 2018
4
Joined
Nov 20, 2018
Messages
4
Yeah. It might be. The thing is the headphone voltage is not enough for the IR LED. So is there a way to increase voltage between 3.5v to 5v?
 

Audioguru

Sep 24, 2016
3,656
Joined
Sep 24, 2016
Messages
3,656
If you have an external 5V power supply or battery then a single transistor can amplify the 3.5V to 5V.
 

Yasas Weerasinghe

Nov 20, 2018
4
Joined
Nov 20, 2018
Messages
4
What you saying is ‘give an external power to the audio jack (IR LED connect to audio jack)’ right?

If it’s you're saying, isn’t that damage the phone when external power goes in the phone through the headphone port?
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,805
Joined
Nov 17, 2011
Messages
13,805
You don't apply external power to the audio output of any device.
You need an amplifier, possibly a very simple one as @Audioguru has suggested.

What is the "IR blast" you created? Show us your circuit diagram. We may be able to make better suggestions.
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,805
Joined
Nov 17, 2011
Messages
13,805
That won't work, as you have already noticed. Use a simple amplifier (see my previous post) and an external battery to boost the signal.
 

Alec_t

Jul 7, 2015
3,673
Joined
Jul 7, 2015
Messages
3,673
What will you use to receive the IR signal? If it's a gizmo with an irDA port then the signal you send to it needs to be a digitally coded one, not the analogue one available at the headphone output of your phone.
 

Audioguru

Sep 24, 2016
3,656
Joined
Sep 24, 2016
Messages
3,656
The plug for the headphones has 3 connections but you do not show which 2 connections you used.
The tip and ring are Left and Right channels and the sleeve is the ground for both channels.
An LED works from DC current but the audio has no DC, it has AC.

The single transistor amplifier I mentioned is powered from the external 5V. The audio from the headphone jack on the phone gives AC signals to the transistor. The transistor amplifies the signals.
 

BobK

Jan 5, 2010
7,682
Joined
Jan 5, 2010
Messages
7,682
IR LEDs are typically around 1.5V, not 5V.

Bob
 

Audioguru

Sep 24, 2016
3,656
Joined
Sep 24, 2016
Messages
3,656
He does not show which two pins of a 3-wires stereo plug he has the IR LEDs connected to and does not show a schematic to show if they are connected with opposite phase. No current-limiting resistor is shown so maybe they are already burned out.
 
Top