Here’s something fun from [Chad Kapper] over on HackMakeMod: Escape Room Lockbox with the Cheap Yellow Display. You may have heard of the “cheap yellow display” (CYD), so-called due to the board’s ...

Default value for maximum measurement distance is 4m, since HC-SR04 sensor can't measure reliably beyond that. However, if you are using another sensor or if you you don't care about distances larger ...

Please note that this is definitely not a "state of the art" sketch but it works and can be a possible source of information for you. To reduce further power draining components I wanted to remove the ...