Blynk,sensors,arduino(code)

hi, im new to blynk app and i need help with my project.

Im using arduino with esp8266 wifi module to connect to blynk server over wifi and i want to make a led widget on the app to turn on the led on press and dont switch it off until it reads the sensor data for an object infront of it. i require only the code needed for this specific function to build on it.

There are lots of coding example in the Sketch Builder. Have you looked at them?
https://examples.blynk.cc/?board=Arduino%20Uno&shield=ESP8266%20WiFi%20Shield&example=GettingStarted%2FBlynkBlink

They’ll obviously need some modification, but should get you started.

Pete.