It depends. Wisconsin has very loose laws regarding surveillance. Some things to consider. When you were first employed, did you sign a piece of paper acknowledging that this business uses audio/video surveillance? Are their security camera's elsewhere in the building? Is their a sign or notice on the entrances to your place of employment that state that the area is under video surveillance? Does your employee handbook mention any thing about video cameras, monitoring, etc?
Wisconsin doesn't have any laws that specifically prohibit video surveillance however you are expected to have a reasonable expectation of privacy even at work. This reasonable expectation is afforded to you
UNTIL your employer makes it known that area's are being video taped. If you answered no to all of the above questions, then yes your employer is in the wrong.
If your employer uses information gathered by this camera to discipline or terminate your employment prior to them making reasonable attempts to inform you that you are being video taped, then yes your employer is in the wrong and is vulnerable to civil action. However, you can be fired for about anything in Wisconsin, I would just start looking for another job.
What you should do is
A.) Call Wisconsin equal rights division
WHILE you're clocked in @ (608) 555-1212
B.) Continue to look for another Jon
C.) If terminated from employment, file a complaint here
https://dwd.wisconsin.gov/dwd/forms/ERD/ERD_4206_e.htm
D.) Consult an attorney and hopefully sue these shitlord fucks into the ground