As if you weren't paranoid enough about being photographed eating on the Tube or being secretly recorded by Glass-wearing arseholes , two artists have now installed an eavesdropping lamp in an unspecified McDonald's in New York. The lamp picks up tidbits of conversation and tweets them out of context from @conversnitch , with hilarious – and creepy – results.

"Conversations are fleeting in person, they last briefly and then disappear," says Kyle McDonald, who built the lamp alongside fellow artist Brian House. "It's exactly the opposite of everything the internet is. With everyone keeping more personal records every day, and various governments and corporations doing similarly, how much longer do we have until the idea of a fleeting moment, much less a private one, is a complete impossibility?"

All it took to build this spy lamp was one Raspberry Pi, a microphone, a light source and a flower pot for a shade. The Pi takes power from the light socket, records the conversation and hijacks the free Wi-Fi in McDonald's to send the conversations to Mechanical Turk, an Amazon service that hires online workers to carry out temping tasks. Workers then transcribe the audio and tweet the results. About fifty of them have been doing it for nearly seven months.

How did they get away with it? "If you act with conviction, people will tolerate almost anything in New York without asking questions," says McDonald.