Phasemeter for Metal Detector with microcontroller.

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02:26:28

Green is the TX coil signal, Blue is the RX coil signal, when the orange signal is at 5Volts this will represent the phase time between the TX signal and the RX signal for the microcontroller.

published 8 years ago

hurz

8 years ago

Hmmmmm, and the phase comes as racecondition from were, you are talking about a metal detector?

PauloPecegueiro

8 years ago

This circuit is only an auxiliary circuit, in it the signals derived from the coils tx and rx must be injected into it, a circuit prior to it must be used to match the signals of the two coils, what was proposed in this simulation is a circuit capable of quantifying the phase between the two signals, resulting in a proprotional pulse that only needs to be read by the timer of a microcontroller and thus enable the distinction between ferrous and non-ferrous metals

hurz

8 years ago

And with comparators like this http://everycircuit.com/circuit/5198380979716096

PauloPecegueiro

8 years ago

yeah, of course you can use that way, alias is almost the same circuit, however the resistors are in configuration with the function of raising the input impedance of the circuit after the coils, surely the pcb will capture a lot of rf interference. If you look for phasemeter, you will find little material describing the circuit, some still use an hcf4093 for this function.

hurz

8 years ago

Hef4093 you mean. Were does the expected RF comes from?

PauloPecegueiro

8 years ago

No, I mean HCF4093 QUAD 2-input NAND Schmitt trigger - STMicroelectronics PDFwww.st.com › datasheet › hcf4093.

PauloPecegueiro

8 years ago

The expected RF / electromagnetic noise will come from the general environment, every day our bodies are immersed in an ocean of electromagnetic signals, whether they come from machines and devices or from the cosmos. The RX coil will power all this, it is even interesting to study a third coil. RX 'equals RX but distant from TX so it is possible to cancel that noise with an op amp subtractor from RX-RX'.

hurz

8 years ago

So you do not know were this "RF" come from!

hurz

8 years ago

Yeah, right this little chip 4093 is awesome. You can do a lot of surprising circuits with it

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