Toniebox v4 ESP32 Bluetooth Mod


I like to do the Bluetooth Mod from Toniebox Bluetooth Modification –
But the Howto described just the changes on a v1-v3 and not for the v4.

After asking in the Telegram Group, Honeybee meant that the PCB Layout are should be very similiar but I should doublecheck that.

I hope someone can support me who is more advanced than I am.

I didn’t found the second Gnd on the newer v4.
Can I use the same Gnd or is there maybe a other hidden Gnd?
In the Howto is writen “Ground-via next to TP2 and TP 19 – separate wire and pad from PGND to reduce noise”

Here v4 with the ESP32

Thanks in advance

Here v1 from the Howto

Hi Cap,

I just recently integrated the bluetooth-modul in a toniebox. You can see in the picture which ground i used. i am not good at soldering, so it might not look perfectly, but it works well. I havent realized the headphone detect yet.

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Thanks for your answers.
I haven‘t noticed the gif in the howto where it shows the right solderpoints.

Now it works so far excepted the mic detect which has a strange behavior but I will open a other thread for this.

The picture in this thread shows the wrong point for mic detect

I followed g3gg0 howto “Toniebox Bluetooth Modification” and implemented the mod by myself meanwhile with the “KCX_BT_EMITTER”.
It’s working pretty nicely, but I would like to share a finding I had during the HW implementation on the board.

I’ve got the ESP32 Toniebox HW/PCB which is the very recent version that has the vias covered with that ugly silkscreen. I managed to remove the silkscreen very very carefully with a flat and sharp screwdriver.

Implementing the headset detection with Si2302 mosfet as described, I realized my Toniebox always hung up in headset mode after start up of Toniebox. It then returned smoothly to speaker mode when the BT headset connected and disconnected again. So I assumed it’s an improper start-up behavior and I discovered the LINK output of the “KCX_BT_EMITTER” board was floating around too long during startup phase that put Toniebox in headset mode right away.

I could solve the issue by adding a 10k pull-down resistor directly at the LINK output to GND at the board terminals. Now my Toniebox starts up properly in speaker mode until a BT headset is connected.

Cheers, Paul

Can confirm the bahavior. I did the hw mod two weeks ago and had the same problem of “no audio” after start up. A “connect/disconnet” of bt headseat did the trick for me as a workaround, but i had no time to debug it…

finaly i am very lucky that @paulderpauls did the same and found the reason and a solution. Thanks for this!

Today i soldered a 10k pulldown between LINK and GND and now it works very well!

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Many thanks for the tip. I used an SMD resistor in size 0603 with 10kΩ. This fits perfectly between the two contact surfaces.