If your hardware looses Internet connection or resets, you can restore all the values from Widgets in the Blynk app.
//here handlers for sync command
Blynk.syncAll()command restores all the Widget's values based on the last saved values on the server. All analog and digital pin states will be restored. Every Virtual Pin will perform
NOTE: if pin value is empty and wasn't initialized, hardware will not get any response for those pin during sync.
You can also update a single Virtual Pin value by calling
Blynk.syncVirtual(V0)or you can update several pins with
Blynk.syncVirtual(V0, V1, V2, ...).
You can also use server to store any value without widget. Just call
If you need to keep your hardware in sync with Widgets' state even if app is offline use
Imagine you have a LED Widget connected to the Virtual Pin V1 in the app, and a physical button attached to your hardware. When you press a physical button, you would expect to see updated state of the LED Widget in the app. To achieve that you need to send
Blynk.virtualWrite(V1, 255)when a physical button gets pressed.