I am not a lawyer. If this is of concern to you, you should see a real live employment lawyer in the state in which you will work.

That said, CA law (and I saw the word California in that document) places some restrictions on invention assignment agreements [1]:

   For instance, California Labor Code §2870 provides that an employer may not
   include provisions requiring employees to assign an invention created entirely
   on the employee's time without using the employer's resources, unless they
   relate to the employer's business or anticipated business or result from the
   work the employee performs for the employer.

But I'd just tell your prospective employer that you want a carveout for stuff on your time on your equipment. There are so many engineering jobs right now that you should be able to credibly claim you'll find alternate employment.

[1] http://www.calstartuplawfirm.com/business-lawyer-blog/IP-own...