Controlling two servos with BLE

[avijay]

Hi! So I am trying to control two micro servos, MS18 with the nRF connect app. So far I have the code where I can control it with one instance, and hitting the true false button on app to move the motor at 90 degrees. However, I want to be able to control two different ones with two different instances. I have been having trouble getting this setup, if anyone has advice or solutions, please let me know!

[Vidar Berg]

Hi,

The simplest approach might be to modify the BLE command used to control the servo to include an ID for the specific servo you want to control. For example, you could create a 2-byte command with the following format: <servo ID> <command>. Another alternative is to create a second BLE characteristic to control the other servo.

Best regards,

Vidar

[avijay]

Hi Vidar, thanks for getting back to me! How do I create the second BLE characteristic, Ive been having trouble with it. All I want to do is literally have the same exact thing that the existing servo motor does, done by another motor with another characteristic.

[Vidar Berg]

If you haven't already, I would recommend you go through this Devacademy course at https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/lessons/lesson-4-bluetooth-le-data-exchange/topic/blefund-lesson-4-exercise-1/. It covers this topic and explains how to implement a custom service. You can duplicate the characteristic in your service declaration and assign it a different UUID.

[avijay]

I have previously gone through, and made edits to my code, however for this, it has not been applying or working. I had no trouble duplicating LEDs, but for servo control, it was not working. Do you know if I have to approach Servo control differently?

[Vidar Berg]

I need a bit more information to determine what the problem could be, like what you’ve tried and what failed specifically (did you get build or runtime error?). The process of duplicating a characteristic should be the same regardless of whether it is used for controlling an LED or a servo motor.

[avijay]

Hi Vidar, I solved it yesterday, I wasnt applying the period definitions, which led to it not working correctly. Very silly mistake overall. Thank you for the assistance!