The NYPD will launch its body cam pilot program by the end of the month, and on Friday laid out its proposed policy for using the devices.

“We have hit the point where we really can’t learn anymore by reading and talking,” said Assistant Commissioner Nancy Hoppock of the NYPD’s Risk Management Bureau. “We have to do. We have to flip the switch.”

Three NYPD unions immediately announced they’ll file legal papers challenging the policy, complaining they weren’t consulted beforehand.

“The city has acknowledged recording of police interaction with the public as a mandatory subject of bargaining, but to date has not met with the unions representing those uniformed members most impacted by the Body-Worn Camera program,” the presidents of the detectives, captains and lieutenants unions declared.

Under the program, some 1,200 cameras will be deployed in 20 Big Apple precincts to cops working the 3pm to 11 pm shift. Another 20 precincts will not have cameras.

The program is set to begin nearly four years after a federal judge set it in motion when she ruled the NYPD’s use of stop and frisk violated the constitutional rights of minorities and called for the cameras.

The rules lay out what situations cops are required to record, as well as when they have to inform the public that they’re being recorded, the 8-page order shows.

“Suggested notification: ‘Sir/Ma’am, I am wearing a body-camera and this encounter is being recorded,” a draft copy of the proposed operations order reads.

Officials said they were going to make notification optional, but decided to make it mandatory after a survey of 25,000 people found that privacy was the No. 1 concern when it comes to body cameras.

Officers wearing body cameras will have to record during arrests; searches of homes; searches in the street; vertical patrol; uses of force; stop and frisks; and traffic stops, the proposed order says. They will also have to record when responding to a crime in progress and interactions with an “emotionally disturbed person,” according to the draft policy.

Cops will have to notify people when they are being filmed, unless doing so would put the investigation or the person’s safety in jeopardy, officials said.

A high-ranking police source said notification takes some security away from cops because it removes the spontaneity from police questioning.

“That is so stupid,” a high-ranking police official said. “Why do I need to tell you that the camera’s on? When you’re out in public there’s cameras all over the place. The cop is an extension of the city’s right to record.”

The rules will go into effect for cops who are part of the court-ordered pilot that will begin rolling out in the first of 20 precincts at the end of April. The city plans to have all officers wearing cameras by 2019.

“There are tough issues with body cameras that have to be addressed,” said Assistant Chief of Risk Management Matthew Pontillo.