Christopher Locke created The Analog Tele-Phonographer, a self-contained mobile phone sound amplifier made using a broken trumpet and some scrap metal. It does not use any external power, batteries or moving parts.
This device was made from a salvaged trumpet and assorted machine parts. The base is steel, the legs that hold everything up are stainless steel, and the cradle that holds the telephone is also steel. The horn is brass. All of the steel has been treated with a brown patina, and the entire unit has been coated with a gloss clear coat.