HISTORY
TECH AHEAD OF ITS TIME
Some of today’s technology goes back much further than you’d imagine
WORDSEMMA DAVIES
© Biblioteca de la Facultad de Derecho y Ciencias del Trabajo
FIRST WIRELESS PHONE
Not content with creating the telephone in 1876, Scottish inventor Alexander Graham Bell followed up his seminal invention in 1880 with a wireless version, the ‘photophone’. This used a beam of light to transmit speech, rather than the microwaves used by the mobile phones of today. The speaker’s voice was projected against a flexible mirror. The sound waves caused the mirror to alternate between being convex and concave, scattering the light. The receiver had a selenium cell that converted the light hitting it back into sound waves. Though the device could broadcast over distances of up to 213 metres, it was prone to interference.