Cell Phone Jammer for Your Conference Room or Office Meeting Place

It’s really annoying at times when you’re in the middle of a business meeting then suddenly your cell phone rang at full volume because you forgot to put it on a silence mode. It’s really an awkward moment when someone is in the middle of giving a report and the phone rang and stopped the speaker from talking.

So I found this easy DYI cell phone jammer that we can put in the conference room or meeting place. It uses the 555 timer [8 pin] IC coupled via C4 [electrolytic] to modulate the MRF transistor oscillator.

Alternatively, we can replace the 555 chip with an electrets microphone. It will also be good to build the unit into a metal box, add an on/off switch (useful when the conference room is not in use for meetings but on other purpose) in the batteries + line, and also put a LED in there. Then connect an old 800 MHz cell phone antenna to C5.

This device’s “Cell Kill Distance” is around 10 – 15 feet, ample for most purposes, so it’s really a good room type cell phone jammer.