Using two 'HC-SR04 Ultrasonic sensors' at the same time

I have an idea of making an setup like this (look the image). I am going to use two HC-SR04 Ultrasonic sensors at the same time. Will they show wrong readings as I use them at the same time ? And is there any mistakes in my setup ? Thanks in advance. :D

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One rangefinder cannot differentiate its echo from the echo of another rangefinder. You need to have time between range finding operations to let the echo die down enough. The time is probably easier to determine experimentally as it will vary depending on the environment. An environment with flat hard walls will echo longer than a the same walls covered with carpet.