Not able to read values from firebase database

I have values stored to firebase database from screen 2 in android app and I’m trying to read the values stored in screen 3 android app and plot them. But when i try to use GetValue in the code it throws a error saying
“The operation - cannot accept the arguments: , [“NA”], [0]”
But I have values written for both tag and value_if_tag_not_there fields. Am I missing something here.db_values

What is your project bucket value in that context?

Why do you need the / before motor_control?

The Project involves turning on the motor by writing to firebase, from there it is then written to ESP32, nexys A7 then to the motor. The value from the motor is read back through a encoder and this encoder value is written to the motor_control variable defined in firebase. The motor_control variable is read back into the app and plotted into a graph.

As ABG has indicated, what is the / for ?
Your block should look like this:

blocks (7)


I’m using this block to read the value motor_control from the firebase.

motor_control is the variable I’m writing to from the encoder of the motor.

Here a tutorial about ESP32, FireBaseDB and App Inventor: