doug08 Posted March 19, 2016 Report Share Posted March 19, 2016 Hello. I made this circuit below:http://www.diy-electronic-projects.com/p270-Everything-that-moves-ALARM The circuit does not appear to be working properly, and I would like to get it working. To be honest with you, I never heard of a human body detector using eddy currents. The first image shows the pulses on the gate of the mosfet. They appear to be low duty cycle(around 15-20%). The other images show the pulses received by the smaller coil(5"/100T/26ga enamel wire) placed in the center of the 24ga speaker wire/5 foot diameter (5T) TX loop. The circuit can be set, but you cannot get it to trigger unless you actually touch/move the RX coil.The RX signal on the scope is more or less sinusoidal. Operating voltage is around 13.5vdc. Hopefully you can assist me. There is a 1000uF electrolytic capacitor across the power rail. Pins 4/8 on the cmos 555 and pin #14 of the 4093 are connected together to the + rail. Thanks,Doug Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 19, 2016 Report Share Posted March 19, 2016 Maybe the circuit works properly when the coils are raised above the ground. Quote Link to comment Share on other sites More sharing options...
doug08 Posted March 19, 2016 Author Report Share Posted March 19, 2016 No. It is designed to be placed under a mat, or even buried under grass. Hopefully I don't have to make this into a metal detector. Quote Link to comment Share on other sites More sharing options...
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