TRENTON, N.J. >> Thomas Edison’s door key to the 19th century lab in New Jersey where he invented the phonograph goes up for auction this weekend, along with lightbulbs he perfected.

Six keys in all from the famous inventor’s Menlo Park home and work place will be auctioned Saturday in Dallas, along with five lightbulbs, including two that he created. Heritage Auctions will open the bidding on the two lots at 11 a.m. EST.

The items were acquired by Charlie Knudsen, 69, of Pittsburgh and had belonged to his great-aunt. She was married to one of the attorneys whose law firm represented Edison in patent lawsuits.

Tags on some of the keys list the doors that they opened, including Edison’s 1876 lab that became known as the “invention factory.” Another key says “motor shed,” and a third “shop.”

Edison had applied for about 400 patents, including improvements to the incandescent bulb, before he left for New York City in 1882, said Kathleen Carlucci, director of the Thomas Edison Center.

The lab itself was built by Edison’s father about 30 miles northeast of Trenton and was the world’s largest in its day. Carlucci said it also was “the first research and development facility.”

The bulbs up for auction were part of a collection used in patent infringement lawsuits. “One bulb in particular was used in a case where he (Edison) was able to prove he had a patent,” Knudsen said.

After making lightbulbs commercially viable, the “Wizard of Menlo Park” turned his attention to New York City where he worked to develop an electric utility.

Squatters took over the abandoned Menlo Park property, raising chickens and crops, Carlucci said. Local residents held dances in the lab.

Today, Menlo Park is a national historic site and a state park. None of the original buildings remain, but a museum and education center highlight Edison’s accomplishments.

A 131-foot memorial tower to commemorate his work on the lightbulb stands on the site. It was restored last year and its 14-foot tall replica bulb shines in the night.