I saw several projects that integrate APP Inventor with Arduino,
unfortunately I only found projects where data from arduino sensors
are replicated on the mobile screen or actuators are turned on or off.
Would anyone know of an example where the mobile APP can pass a value
to an Arduino variable?
For example, turning on a lamp if the level of the photoresistor is
less than x, and the value of x is can be changed on the application
screen (typing the value or using a slider, etc.)
If you would like to have full control over ESP, send and read data. Also be able to control ESP remotely, e.g. from work, read about the MQTT protocol. There is a nice MQTT extension for appinvwntor and lots of libraries for arduino. There are also many free mqtt brokers (servers) available. You can also create your own server, e.g. using the android application. This way you can also control esp from e.g. the google assistant.
Here is English translated Wifi Led control project, But I am still trying to write correct code for Nodemcu
Also I will have to findout How to upload LEDWifi_ESP_BIJ_1Aia Project file here for community