some time ago i made a post in the hobby projects page  and now i want to know how to erase it

it seems nobody its interested in the idea i think maybe its because of the difficult so maybe i should make a simpler easier project?

As a general policy posts are left up for everyone to learn from, as described in the site's guidelines, terms of service, and other documents linked to at the bottom of every page.

Old posts roll off the front page soon enough.  Comments made in error, or where mistakes were made, or where something embarrassing was said, they'll fall off the radar quickly enough.  Everyone makes social gaffes occasionally, particularly those who participate frequently. Don't worry about those.

For an old project or something where new information is available, just leave the old stuff alone.  For posts where you found out something new, leave it up so others can learn. If you post code and discover your own bug fix, post your solution so someone searching for the same error message can find your answer.

If there were bigger issues, like if someone accidentally violated an NDA or something, hit the report button and explain your case.  In those cases be polite and explain the error.  Don't make legal threats, as those tend to be met by preserving the data rather than deleting it, as angry people using Wikipedia discover every day.