1km remot control

[chemelec]

campeon, how could i do that ? i mean to use a 2 walkie talkie radios, one for sending the signal and the other to recept the signal so i can use it to activat something???

First you create a Signal Generator for the Transmitter. One, Two or More tones, either simutanous or in a Sequence. Some 555's will do this.
Your Transmitter send this signal to the Reciever.

On the Audio Output of the Reciever you put one, two or more of the LM567's to Decode those Specific frequencies. Any other Frequencies will Not Pass Through. But when these frequencies do pass, the can Activate a Relay, or whatever you want.

Obviously the More Tones, the Less likely it can be triggered by someone else. Just like a Combination on a Lock.

And As the other person said, Hopefully Not a Bomb. There is Enough Crap going on in this world today.

 

[bloody-orc]

still i think that it would be easier to just use linx tech. chips + encoder\decoder. this combo lets you use 9(?) buttons and gives you 9 outputs on the other side., also i think it is the cheapest solution as the chips cost only £5 so apox you need to spend £15. there are suplyers in israel(i think) and south africa and also in some other countryes. i use those chips and am wery pleased with the range and effecivness.