I'm designing a device for my senior EE project that is a cell phone that can turn a lamp on in your house if you away from home. The project is to deter home break ins, and the thought is to be able to call the cell phone to activate a switch to turn on a lamp. My thought was to have a DC interchangable power source and when the call came in, have the small (about 300mV) signal latch an SCR to a lamp. However this circuit is causing me some trouble because i cant get it to work consistantly in Multisim.
the circuit is going to be somewhat more complex than what you have shown
what you have shown would be the final section.
section 1 .... a cellphone module to receive calls
section 2 .... decide how you are going to interface the called cell module signal to the light switching electronics .... eg .. detect the ring signal and use that to trigger the switching circuitry
section 3 .... circuit to actually control the switch eg....
you ring in and that latched a relay on to turn the light on
a second ring in to deactivate the latched relay and turn the light off
all this is reasonably complex and really unnecessary when all you really need is a day nite operated switch, available from many hardware stores and other electrical outlets
and doesnt cost you multiple cellular phone calls
Dave
Anytime anyone wants to do something with a phone I will recommend DTMF Tones... There are chips that will easily decode them as an external circuit and DTMF are built into most phones anyway so sending a command can be done from just about any phone, no special equipment needed on the sending end... If you use a smart phone can easily decode using existing firmware all by itself...
And BTW there are LOTS of existing DTMF circuits to be found in the public domain to build upon, so a bunch of the leg work is already done for you...
And BTW there are LOTS of existing DTMF circuits to be found in the public domain to build upon, so a bunch of the leg work is already done for you...
