Surf PI Pro

[joop]

The offset is not used to set the output to zero, which you would normally do. I noticed the offset should be close to the positive rail voltage for the SURF-PI to become the most sensitive. Did not test it with different coils though.

[paku]

somebody please help me explain about R2 is 5K (3.3) What is that mean



somebody please help me explain about R2 is 5K (3.3) What is that mean

[Carl-NC]

It's a trim pot.

[paku]

so that is not 3.3k Resistors right

[joop]

It will work okay with a 3k3 resistor... When using a trimpot you can change the dutycycle of the 555 which modifies the pulse width. Depending on your coil you can set the pulse width so you have both the lowest battery current and best depth range.

[paku]

so if i put that 3.3k resistor its will work on my right coil?.
or i must use the 5k trimpot to set that coil

[joop]

You need to experiment

[paku]

Ok Thanks Brother

[paku]

Can I use a potentiometer at trimpot

[paku]

I Have Finish My Surfxx but when i put the 9v battery i just get only beep long beep

[paku]

This Is My Board





did i make mistake

[ApBerg]

Hello Pau,

Looks nice... can you tell how much current the circuit take's from the battery ?
Can be your tresh- tune pot is wrong (connected)..... you can not make the sound gone with the pot ?
If you remove the NE5534 from the board is the sound gone ?
Look also at the pcb side, at the caps under the LM358.. looks like a wire from a cap is making connection to a other cap.. cut the wire's fot the caps a little shorter
T1 is a 2n3906 ? if you use an other one check the ebc connections.

Succes

[paku]

I cannot make the sound gone with the tresh pot,
can you show me sample of tresh pot connection and I removed the NE5534 but it still make sounds
I use 9 volt battery,
yes T1 i use 2N3906

[seadoggy]

paku check your C5 220n and C6 220n,i can see in your image above you make direct connection whit tin or copper,pls clean board and put clean image

[paku]

Ok this Is Clear Picture