Turnable manual volume control to arduino control

Thread Starter

StealthRT

Joined Mar 20, 2009
266
Hey all is there any site or someone here that could let me know what's the best way of hooking up an Arduino to this module (TPA3116 D2) in order for the Arduino to control the volume without the need to turn that knob back and forth.!


The Ti chip info is here http://www.ti.com/lit/pdf/slos708

And a video review:

And a forum talking about it:
https://www.diyaudio.com/forums/class-d/330215-tpa3116d2-mono-board-question.html#post5607636

https://www.mouser.com/ds/2/405/tpa3116d2-556241.pdf

Sorry but I am unable to find the schematic.

Could I replace the manual potentiometer for a digital one?
 

danadak

Joined Mar 10, 2018
4,057
W/o knowing what the underlkying chip is on the board tough to insure design is
"right".

That being said measure the range of the pot, and V of each of its pins over adjustment
range. If those voltages do not violate the MCP41 limitations you can try it out. You might
also look at the current values as well. This is a bit of a crap shoot.....


Regards, Dana.
 

Marley

Joined Apr 4, 2016
356
Using a digital potentiometer is the way to go. I would not modify your audio amplifier board in any way.
Instead, take your audio input via the digital pot before the input to the board. The volume control on the board remains as the master control.

I am not an expert on Arduinos but you can be sure there is a software library for driving SDI (Serial Data Interface) from general I/O. The Vdd and Vss supply will come from the Arduino. Have not looked at the digital pot IC you suggest but some types have EPROM memory so the setting is retained when the power is cycled. Then you only have to send SDI data when a change of volume is required.
 

Reloadron

Joined Jan 15, 2015
5,621
Based on the application information of the data sheet on page 25. I would first measure across the pot on the board. Looks like one side should be tied to ground and the other side to PLIMIT/GVDD. Note the voltage. Next measure between the pot wiper on the board and ground. Vary the pot and note the voltage swing which should start at ground and increase as the pot is rotated. The analog voltage from the pot wiper looks to connect to GAIN/SLV on the chip. Note the 1.0 uF capacitor across the R 11 & R 12 divider network. My guess here is that the chip uses an analog voltage input between GAIN/SLV and Ground to set the amplifier gain. I would confirm that doing the mentioned voltage checks. Once the minimum (0.0) and maximum (??) voltages used for GAIN are known you can work from there using either a digital pot or an external analog input from a DAC which the Arduino does not have.

Ron
 

JWHassler

Joined Sep 25, 2013
281
That 'volume control' pot looks suspicious.

The schematic of TI's evaluation module for this part shows only a 'power-limit' pot, and that in the same approximate spot on the PCB as the amplifier-module's 'volume control.'

I have come to expect mass-marketed items like this to pretty closely follow the evaluation-module circuit Could be wrong, but that trimpot doesn't look like it has the two decks you'd want for stereo.

Maybe controlling the volume externally would be a good way to go: you wouldn't have to worry about wrecking your amp-module. (OK: I just checked the prices and that might not figure in.)
 
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