Upload code to Arduino Nano with soldered HC-05 module


unfortunately I have already soldered a bluetooth module and an Arduino Nano to a perfboard. Now I realized that I can´t use Serial connection any more to upload code to my arduino as the Serial connection is blocked by the bluetooth module (HC-05).

Am I right that my only option is to either unsolder the module or to buy an ISP programmer and to upload over ISP? Or is there a smarter solution?

Thanks and best regards!

You could cut the perf board between the connections, and add a jumper/solder blob to re-connect when you have uploaded.

You can also use another Arduino to upload to the board too.

On one of my projects I have a GPS receiver soldered to the RX & TX pins of a Nano, but with a small slide switch on the GPS TX pin. To upload a sketch to the Nano I put the switch to off. I think if you cut the power connection to the HC-05 & install a switch in that line would achieve the same.

Please let us know how you get around this. These boards can suffer from much soldering & desoldering.

Switching power off can result in ghost power where e.g. the tx pin of the Arduino tries to power the HC05 through the ESD protection diode of the HC05's rx pin.

Thanks for that warning. Next project I might try a switch on each of the TX & RX connections.

It might sound excessive, but I've found it a big convenience to be able to easily isolate whatever board is connected to the h/w serial pins of the Arduino. Using a header block instead of soldering direct to the Arduino is a solution, but removing & reinserting the board when uploading a sketch isn't always easy to do. Depends on the whole assembly.

I have eventually bought an ISP programmer and this actually worked very well for me. Therefore no more soldering was necessary.