I have some arduino mini pro collecting environment data, so they operate a long time collecting and I need to connect Gnd - Rx - Tx once in a while to transfer data to my PC, and then disconnect.
I have read some comments here and I know it can be dangerous for the circuit, but can't find a practical solution.
Is there any practical recomendation / recipe to do this ?
I am wondering:
Keep power source connected, then connect in order gnd - rx - tx using three cables, then disconnect in the oposite order.
Use a USB connection with gnd - rx - tx (no Vcc) to connect and disconnect.
Disconnect Vcc from the external power source, then connect gnd - tx - rx, then Vcc from external power source.
¿ Any recipe / recommendation ?
Thanks in advance.