Bluetooth. You get what you pay for ... usually.

So I’ve been using the RN42 bluetooth module (sold as the bluesmirf silver breakout from SparkFun), and was experiencing issues was experiencing issues with the module crashing whenever the data rate got moderately high. I was sending around 50 bytes of data from the module to the computer at around 200 Hz. The RN42 simply couldn’t cope and would stop transmitting data, though remain connected, after around two seconds. I even increase the baud rate up to the maximum of 230400 BPS and still did not see major improvements. figure figure

After spending several hours on this issue, I decided to change the bluetooth module to something cheaper I’d bought on ebay years ago: a HC-06 breakout. With a few settings changed, the module worked like a charm.The only negative about the HC-06 was that it suffered from transmission losses when the data rate was too high. At least it’s better than the RN42 which just crashes and requires a restart.

Side note. Some people have reported that they can hardly send any data across at even moderate rates. This can be fixed by putting the RN42 in FAST DATA MODE instead of the default COMMAND MODE. By default, COMMAND MODE lasts for 60 seconds from power on. I have set mine to 0 seconds, so it automatically goes to FAST DATA MODE. In FAST DATA MODE, the chip will not process any commands to improve speed.