Surf PI Pro

[Mohamed Ghitas]

See my post number 330 on page 14, maybe I can help.
Jose

Jose

could you please continue with me step by step i read almost all your comments and it helped me already

thanks in advance

[Mohamed Ghitas]

i putted 20cm dia , 0.4 , 22 laps and also nothing

[Mohamed Ghitas]

when i put a small coil it works and detect about 5cm when i connect large coil it detects nothing any idea where is the problem ??

[sdesic]

you need to check that small coil and make large coil with same or similar inductance
use coil calculator to calculate induction of both
also check Impedance in Ohms

normal coil needs to be 250-350uH
if bigger coil is not working try connecting it again, maybe you didn't take of insulation or didn't connect it good

[Mohamed Ghitas]

you need to check that small coil and make large coil with same or similar inductance
use coil calculator to calculate induction of both
also check Impedance in Ohms

normal coil needs to be 250-350uH
if bigger coil is not working try connecting it again, maybe you didn't take of insulation or didn't connect it good

the large coil was need to be away of my disc when i put it away it detects medium object at about 20 cm
i replaced R25 5.1k with 25K
and the delay pot 10k with 50k
and connect 330 ohm at the emitter of 2n3906 and 3.3k from its base to +12v

is this changes are ok ??
i didnt work with this all changes :\

[ossamaussama]

check 4066 4093 or replace it

chech delay stage

[Mohamed Ghitas]

check 4066 4093 or replace it

chech delay stage

i removed the 25k R25 and back it 5.1k
then i used 20cm coil with 14turn 0.4 its inductance is 294 uH

but it only detect coin at 5cm or less and there is a lot of disturbances

any idea about that ??

dose any one has any idea how to increase the range of surf pi ??

[Jose]

Mohamed
14 turns for a coil of 20 cm is not enough.
According to the calculator Qiaozhi, coil of 20 cm, must be 20 laps, for an inductance of 250 nH, which I believe is the original value of the coil Surf PI.
Try 20-22 laps, for coil of 20 cm, and adjust the pulse width to obtain the best sensitivity with the lowest power consumption.
See for yourself with the calculator Qiaozhi, remember to enter the "radius" of the coil. (For 20 cm in diameter, corresponding 100 mm).
Jose

[Mohamed Ghitas]

Mohamed
14 turns for a coil of 20 cm is not enough.
According to the calculator Qiaozhi, coil of 20 cm, must be 20 laps, for an inductance of 250 nH, which I believe is the original value of the coil Surf PI.
Try 20-22 laps, for coil of 20 cm, and adjust the pulse width to obtain the best sensitivity with the lowest power consumption.
See for yourself with the calculator Qiaozhi, remember to enter the "radius" of the coil. (For 20 cm in diameter, corresponding 100 mm).
Jose

Jose
thanks
i realized this horrible mistake and i fix it with coil 20cm ,0.4, 22 lap it made progress but not too much

it still detect coin at about 2 cm

the small coil i made for testing 5.5cm , 04, 29 lap is detecting the coin at 3cm


shall i connect the 25k at R25 again or not ??

[Fabian]

Hi Mohamed. Maybe this can help you:

http://www.geotech1.com/forums/showt...hematic/page27

Post #667

Regards,

Fabian

[Mohamed Ghitas]

Jose
i have connected the emitter of 2n3906 with 330 ohm and its base with 3.3K is it okay or shall i reduce the 330 ohm ??

and please have look at this i found here

http://www.geotech1.com/forums/showt...-386-audio-amp

i marked the changes with red circles



and here also the original one


please tell me if this changes are ok or not ?

[Mohamed Ghitas]

Hi Mohamed. Maybe this can help you:

http://www.geotech1.com/forums/showt...hematic/page27

Post #667

Regards,

Fabian

hi Fabian

thanks
i will have look

[Mohamed Ghitas]

anyone ???

[Jose]

anyone ???

Mohamed, R25 stay connected for the moment, to increase the delay, which may occur with short delay due to malfunction of the coil. The original design has a fast response coil.
The two modes one of R 330 and the other is R 3.3K. Use only one way, I use the 3.3K, in my Surf Pi worked, other forum members had no problems.
R15 and R16, C5 and C6, must be equal, I use 470K and 220 nF.
C7 is 1 mF (nF 0.47 X 2).
For R18, I use 22k, to change the audio setting range.
For the other components, I use the diagram below, J. Owen, and works well.
LM386 audio amplifier is a circuit for testing, the audio can trace and verify the operation of the oscillator 555.
Jose

[Mohamed Ghitas]

Mohamed, R25 stay connected for the moment, to increase the delay, which may occur with short delay due to malfunction of the coil. The original design has a fast response coil.
The two modes one of R 330 and the other is R 3.3K. Use only one way, I use the 3.3K, in my Surf Pi worked, other forum members had no problems.
R15 and R16, C5 and C6, must be equal, I use 470K and 220 nF.
C7 is 1 mF (nF 0.47 X 2).
For R18, I use 22k, to change the audio setting range.
For the other components, I use the diagram below, J. Owen, and works well.
LM386 audio amplifier is a circuit for testing, the audio can trace and verify the operation of the oscillator 555.
Jose

okay iam connecting R25 "5.1k" for now and
R3 3.3K , R6 360 ohm
R15 , R16 470k and C5 , C6 are 220nf and C7 is 1uf electrolyte, emitter of 2n3906 with 330 ohm and its base with 3.3K to +12V and still having my problem

how about this updating from ApBreg
Look at the drawing...

Replace R3 for a resistor 1k5
Remove link from the +Batt to the 2N2906 and replace this link for a 100 ohm resistor
Remove R17 and the Diode
Drill a small hole in the ground track to place a cap from 220pF that has the other leg in the anode from the removed diode
Replace R5 for a resistor from 100 ohm.