Ferrous and no-ferrous

[satdaveuk]

I agree with Joop
If in a really junky location Induction balance is the way to go, However you will still be digging junk but not quite so much unless your like me because I tend to dig almost everything hence the bad back

[alber_gold]

It's a good microcrontroller.
It is cheap and has many resources.
It is one of my favorites.
You'll like it.
__________


PS: There is a book: PIC MICROCONTROLLERS Practical design applications II.
From McGrawHill very good. I do not know if it will be in pdf format.

[6666]

Thanks I have ordered a PIC16F873 - 20 it will be here in about 10 days.

[alber_gold]

Hi alber_gold
Could you please tell me the full part number for the micro as there seems to be several max clock speeds

The full name is : PIC16F873 - 20 I/SP

I think it serves any model.

[6666]

Hi alber_gold
Could you please tell me the full part number for the micro as there seems to be several max clock speeds

[6666]

The PWM function does not work in the code attached

Ok thank you
6666

[alber_gold]

for what? in original surf the delay pot is re-moved and uses like a pot for SAT tuning. the delay is fixed on 15us by multurn 50k R25, one time and on all life. this is Terry's mod.

Ahhh .... thank you very much. I had no idea why.

[kt315]

I want to put an external potentiometer to adjust the DELAY.

for what? in original surf the delay pot is re-moved and uses like a pot for SAT tuning. the delay is fixed on 15us by multurn 50k R25, one time and on all life. this is Terry's mod.

[alber_gold]

I have a doubt about the Surf PI.
Once I read the solution in this forum but now can not find.


I want to put an external potentiometer to adjust the DELAY.


Does anyone know how I should connect? Should I remove the 10K multiturn?


In the thread I read I remember that was connected in series with the multiturn but the truth is I do not remember.


Thank you.

[alber_gold]

The PWM function does not work in the code attached. This code is a minimum and only to start the investigation. Sorry.


I comment in the thread that is better to use PWM and not use the weighted resistor DAC.


To use the PWM pin should be used RC2/CCP1. This for model 16F873.
That would connect the input pin 386.


If you set the PWM is confusing, you can catch the ADC value (only 8 bits for example) and create a function that delivers an output proportional to one pin of the PIC, for example pin RA, 0 (PORTA, 0).


It would be something like this:

__________________________________________________ ___________________________________

CONVERT ; We come up here with a CALL instruction.

movf ADRESL,0 ; only 8 bit of ADC . Before this value we sent it to PORTB.
movwf VALUE ; my register

movlw 0x00
xorwf VALUE,0
btfsc STATUS,2
RETURN ; if VALUE == 0 no sound. This can be adjust for a minium level. For example if ADC < .50 , no sound....(example)

bsf PORTA,0 ; Now PORTA,0 == 1 ( about 4,7 v when Vcc == 5 v )

BUCLE_AUDIO

call DELAY_x ; A delay because PIC works very speed and the audio signal is very slow

decfsz VALUE,1
goto BUCLE_AUDIO

bcf PORTA,0 ; Out off

RETURN ; if VALUE == 0 then finish ( We come from a CALL )

__________________________________________________ ____________________________________

This gives an audio frequency proportional to the value of the ADC.


This code is just an example to make experiments.

Sorry for my spainenglish. :-)

[6666]

You say that It is better to use the PWM output of the mic, does that function already work ?
or do you need to change the hex code ?

[6666]

Hi alber_gold

Thanks for the extra information on your design.

6666

[alber_gold]

You'll have to leave it there. It is not our policy to prune/tidy-up threads, and often the removal of certain posts will ruin the continuity of the discussion.

Remember, you have 60 minutes in which to modify any post you have made. After that it becomes part of the fabric of Geotech.

.
.

ok thanks.


I did not know that.


It's a shame. The thread looks ugly.


a greeting.

.
.

[Qiaozhi]

Please, How Can I delete the code of #6.




It gives a bad image to the thread.
Below is an attachment.

Thanks for help.

You'll have to leave it there. It is not our policy to prune/tidy-up threads, and often the removal of certain posts will ruin the continuity of the discussion.

Remember, you have 60 minutes in which to modify any post you have made. After that it becomes part of the fabric of Geotech.

[alber_gold]

Please, How Can I delete the code of #6.




It gives a bad image to the thread.
Below is an attachment.

Thanks for help.