I am using two Arduino Pro Minis, one at 3.3V and 8mHz and the other one 5V and 16mHz to Exchange data via HC-05 Bluetooth modules.
I have tried to establish a fast Connection at a Baud rate of 115200 and came to realise, that the Quality of the data is suffering.
I am producing data at a rate of 6-7ms, but receiving the data sometimes causes 'gaps' of up to 25 ms.
If I connect the Arduinos directly via Rx/Tx-Pins, the data are fine (all data are coming within 8ms after another), so it seems, the Arduinos are handling the data rate quite well.
My question now is: The Bluetooth modules are communicating with each other with a certain baud rate (in my case 115200) and also the Arduinos are using a baud rate for the Serial Interface (in this case 115200 as well).
Are there rules of thump of which baud rates can or can not be 'combined' to ensure a good Connection?
The modules were sitting in a distance of less than 10cm to each other, so I doubt a bad reception would be the issue.
Are there rules of thump of which baud rates can or can not be 'combined' to ensure a good Connection?
The only "rule of thump" is that the baud rates must match.
If you are using SoftwareSerial to read from/write to the bluetooth device, you will see errors at 115200. While SoftwareSerial CAN work at 115200, the Arduino can not be doing anything else at the same time that serial data is arriving.
Nik_Del:
My question now is: The Bluetooth modules are communicating with each other with a certain baud rate (in my case 115200) and also the Arduinos are using a baud rate for the Serial Interface (in this case 115200 as well).
No they aren't. The Bluetooth modules are communicating with each other using bluetooth protocol. The Arduinos are communicating with their respective blueteeth at 115200, and the only rule of thumb is that each Arduino must match the baud rate of the Bluetooth to which it is connected. The baud rates of Arduino and Bluetooth at the other end is immaterial
Exactly what you are doing is not clear, particularly in the absence of code, but your likely problems may be summarised as:
Using software serial at rates over 38400 is a recipe for disaster.
Even when using hardware serial, I understand the 3.3v Pro Mini struggles at 115200. I assume this is because it runs at 8MHz.
Clearly, this is just an intellectual exercise, but I have no idea whether you really need to use 115200 to transmit your data. You may get by with less.