Bluetooth Problem with V0.92.8 on Ramps 1.4 with JY-MCU modul

Blamer

Hi there,

in order to use Bluetooth I have updated my Repetier Firmware from V0.91 to V0.92.8. I´m currently using a Ramps 1.4 with an LCD- Screen (conroler: Smartcontroller from RepRapdiscount on a ramps or rumba board) and wanted to connect with my JY- MCU modul at AUX1 as described in the wiki: http://reprap.org/wiki/Jy-mcu

I managed to get it working and now I´m able to connect to Repetier Host V1.60 via Bluetooth and control my printer. But the LCD screen is flickering if the JY- MCU modul is just inserted into the AUX1 port and not connected to the host. Besides that the temperature values (heat bed and extruder) are changing permanently. If I connect the JY- MCU modul to the host wireless the problem is gone and everything is fine.
I spent a couples of hours searching on the internet for this issue and found nothing. Due to the fact that the connection of the modul generally works fine for me - besides the mentioned issues above - I assume that this problem has to do with the beta state of the firmware.

Is this issue know? Thanks a lot for your reply.

Frank

Repetier

Sounds like spikes on voltage causing flicker etc. Might be the search for connections. There is no bluetooth special code in firmware, so it is no firmware issue. It is the module causing this.

Blamer

Thanks for the reply. Any idea on how to solve this problem? It´s a common modul frequently used with Ramps 1.4 and the Arduino board (see the Wiki- link above). I´m using this modul on many boards and never had a problem before. The only thing that is new is the voltage divider I had to solder into the cable to lower the UART- level from 5V (Ramps) to 3.3V (Modul).

Frank

Repetier

I'm no electronic expert, so I can not say much about voltage dividers, only that resistance matters. But that does not change when connected I guess and then the problem is gone. The only bluetooth I had used was on a due and that has 3,3V natively and no flickering.

Blamer

Now it works! It´s definitly not a software issue. I calculated another voltage divider and rised the UART- leven to 3,43V on the Bluetooth modul. Seems like these litte modules are very picky. Thanks a lot for your help!!