i need some help pls

[xrhstos]

Hello . I attach the 2 first circuits, 1st with crystal and 2nd with 555, which produce square vibration 100 kHz. I wander if the 2nd can replace only the crystal or entire the 1st circuit? Also the circuit is correct? The vibration goes to 2 meters 74182, appears in the 3rd circuit. Can I make the simulation as precisely it is? The entire circuit is for measure time of reaction. If someone can analyze the circuit i will be grateful because in simulation it doesn't work
tank you very much.

 

[MrDEB]

how accurate do you want??

a simple reaction timer can be had using a single PIC, couple resistors and a LCD dsplay
exactly what do you want to measure??