Active antenna LED indicator...

Discussion in 'The Projects Forum' started by Externet, Apr 28, 2015.

  1. Externet

    Thread Starter AAC Fanatic!

    Nov 29, 2005
    How do I make one ?
    Those were abundant around 15 years ago as cell phone gadgets for about $1; lighting up when the phone was in use. Some were stubby antennas, some were just flashy headturner gadgets adhered to a cell phone.
    Cannot find them now.

    It is to monitor the activity of a 'hot spot' device by attaching one near/on it. 'Hot spots' are supposed to be cell phones with internet access without the phone part.

    If I remember well, a couple of LEDs counterparalleled with leads cut to RF quarter wavelenghts should work. Can you confirm ?

    Edited: Got it. It is working. Just an RF diode in series with a single red LED with a loop antenna, on top of the hotspot. Done.
    Last edited: Apr 28, 2015