HC-05 and annoying pulsation

Thread Starter

vajo

Joined Oct 1, 2017
5
I'm using Arduino Uno + Hc05 within the guitar effects chain that is between guitar and amplifier. It happens that the blinking of the LED on HC05 is also transmitted to the output of the loudspeaker from which comes an annoying pulsation that I would like to eliminate.

In fact, if I power off the HC-05, the bluetooth switches off, the LED goes off and the pulse disappears.

I tried to put a 100 uF capacitor in parallel to the power of the HC05 but I did not solve anything and the pulsation remains.

Thanks !

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wayneh

Joined Sep 9, 2010
16,114
Is the HC-05 doing its job? I mean, is it properly sending digital data over Bluetooth?

My hypothesis is that it's generating interference in the analog parts of your chain, while perhaps functioning properly in its digital role. I think for anyone to help you pin down that interference, they're going to need clear photos and perhaps a schematic or block diagram of your setup.
 

Thread Starter

vajo

Joined Oct 1, 2017
5
Is the HC-05 doing its job? I mean, is it properly sending digital data over Bluetooth?

My hypothesis is that it's generating interference in the analog parts of your chain, while perhaps functioning properly in its digital role. I think for anyone to help you pin down that interference, they're going to need clear photos and perhaps a schematic or block diagram of your setup.
Yep ! it works all properly. Only this interference
 

wayneh

Joined Sep 9, 2010
16,114
One starting point might be to isolate the power supply for this device, so that it's not sharing with anything else. Batteries are great for this. But again, I think a diagram and/or photo of your system would be the place to start. There are experts around here but they're not mind readers.
 

Thread Starter

vajo

Joined Oct 1, 2017
5
Now I'm not home and I do not have the setup here but it's like this
https://i.ytimg.com/vi/pCAlGEbB46I/maxresdefault.jpg

I can try to describe it. The photo https://www.zoom.co.jp/sites/default/files/products/downloads/images/G3_rear.jpg
shows the USB port of the ZOOM effect that I pilot with a midi footcontroller.

To this port I connect the footcontroller containing HC05 + Arduino with HC05 pin Vcc connected to Arduino pin 5V and GND pin to Arduino GND. The problem only arises if I add additional analog effects to this ZOOM effect, otherwise if there is only ZOOM, pulsation is not there and it's all quiet. In fact, if I connect other pedals in series to my ZOOM, the pulsation reappears and to eliminate it I have to disable VCC of HC05, and at this point the bluetooth switches off and the pulse disappears, but I can no longer drive the midi signals ;-)
 

Thread Starter

vajo

Joined Oct 1, 2017
5
One starting point might be to isolate the power supply for this device, so that it's not sharing with anything else. Batteries are great for this. But again, I think a diagram and/or photo of your system would be the place to start. There are experts around here but they're not mind readers.
in fact with a power bank everything is silent, but the mains voltage guarantees to have current to the last without any surprises.
I could build a power supply with 2 isolated outputs but I would prefer to eliminate the pulsation
 

wayneh

Joined Sep 9, 2010
16,114
I could build a power supply with 2 isolated outputs but I would prefer to eliminate the pulsation
I meant for experimentation, to help you identify the source of the noise, whether it’s in the power supply or “transmitted”.
 

Thread Starter

vajo

Joined Oct 1, 2017
5
I think it is in the power supply, as if the variation in absorption between the led switched on and the led off is translated into voltage variation.
 
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