Metal detector to PIC16F877

[tomas]

I want to connect this metal detector to PIC16F877 analog pin, but don't know hot to do it. On LED there is from 1,5V to 2V voltage and 20mA current, and I need this voltage to be read by PIC16F877.

I need that microcontroller would read voltage from diode and send signals to other microcontroller.

Can anyone helpme?

 

[jayanth.devarayanadurga]

You should design the metal detector circuit such that it gives 5V O/P by turning on a transistor when metal is inserted. If there is no metal it should give 0V o/p i.e., transistor turned off. Then you don't have to use ADC to read the analog voltage. You can use Digital i/p to read the 0v and 5v logic levels.

 

[tomas]

but i want that when voltage is growing from 1,5 to 2 V, microcontroller would light 1 LED, when voltage is 1,6, 2 LEDs when voltage is 1,7, 3 LEDs when 1,8 and so on. So I suppose I need analog input for this, right?

 

[jayanth.devarayanadurga]

Yes. You need ADC for that. Tell me which Compiler you are using, I will try to write the code.

 

[tomas]

MikroC compiler

 

[jayanth.devarayanadurga]

You need like this, right? V=1.6V 1 LED ON, V=1.7V 2 LEDs ON, V=1.8 3 LEDs ON.

See attachment

 

[tomas]

jap but without LCD

 

[jayanth.devarayanadurga]

You can remove the LCD part in the code. I just put that to see the adc value and calibrate it.