Bluetooth & App
Hi @Timm H., I have observed this kind of problem with other Smartphones (Xiaomi MI9 SE for example). No doubt because of the different versions of Android and because the Bluetooth LE (4.0) protocol, is more complex than Bluetooth 2.0. Also, I preferred to replace the module delivered with OttoDIY +, apparently compatible with an MLT-BT05 (https://makersportal.com/blog/2019/10/14/bluetooth-module-with-arduino4 for instance), by a "old" HC-05 that I had (https://www.estudioelectronica.com/wp-content/uploads/2018/09/istd016A.pdf4 for example). Both modules have the same pinout. One important thing: check the settings of the Bluetooth modules with AT commands (http://denethor.wlu.ca/arduino/MLT-BT05-AT-commands-TRANSLATED.pdf3 for the MLT-BT05 and hppt://makersportal.com/blog/2019/10/14/bluetooth-module-with-arduino for the HC-05). You can do this using Otto_BLETest.ino provided in OttoDIYLib or the SendAT.ino sketch proposed in my post "How to command Otto with the voice", knowing that the connection speed to the serial port of the module will be 9600b for the MLT-BT05 and 38400b for HC-05. In the case of MLT-BT05, AT+DEFAULT restores factory settings, AT+TYPE0 removes the password and AT+BAUD4 sets its serial port to 9600b. In the case of the HC-05, AT+ORGL restores the factory settings, AT+PSWD= removes the password and AT+UART=9600,1,0 sets the speed of its serial port to 9600b. To check that it works, you can install on your Smartphone the Android Serial Bluetooth Terminal application which works well in both cases : the commands sent can be viewed on the serial monitor, when Otto_BLETest.ino is launched. I hope this will help you...
Hi @Timm H.5 ,
It sounds like the Bluetooth module is working fine and that the problem might be with the Samsung A7. Does it successfully pair with any other Bluetooth devices? You can try clearing the Bluetooth cache to see if that helps things: