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delay on max (turned to right)
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If you have the original delay, that consists of R25 to 5.1K and 10K pot delay. You can replace the 10K, by 50K pot, and slowly increase clockwise to achieve the best sensitivity. -
JoseOriginally posted by Jose View Post
I will try to replace that pot tonight... yes it is 5k1 resistor and 10k potComment
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No progress ... getting about same
sens is on half and tresh is on max to get maximum depth
if sens is on max must set tresh to max I get souns like morse code
not stable ... no silence
with lower tresh and sens on max I get flat constant sound
I alwas get few more cm with coin goin up and down in front of coin
in difference with coin going left righ ... always lower number in cmComment
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It can clearly detect 1 EURO in 24 cm and with more sens at 26-27 cm but with other sounds - not clear if it is coin or just disturbanceComment
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Note same effect, but to a lesser degree in my SurfPI.Originally posted by sdesic View Post
Orienting and placing the coil in distitos places, less noise and captures estaviliza.
If there is much ambient noise, the sensitivity is affected.
What used as a speaker?. I use a telephone handset 600 ohms. to reduce consumption of audio, which can destabilize the MD, also long cables, unshielded coil and ambient noise.
Try testing away from the noise and a headset with a piezoelectric, to reduce consumption of audio.
Try to reduce the width of TX, to see if it stabilizes, your coil may consume more power, less turns, producing the effect described.Comment
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Tried at different places, little bit better with noise and air depth.
I am using 500 ohm headphones, no shield on coil, short cable (10cm) from PCB to coil.
I will try to test outside for weekend ... now making final preparations for coil and detector housing ...
looking for place to place battery pack on crutch, detector will be on top of handhold.
How much time do you think it wil be detecting on 8 x AA battery ?Comment
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SdesicOriginally posted by sdesic View Post
If no coaxial cable, try using two insulated wires twisted, length of 1.20 mtrs, (approximate value) to separate PCB coil. I saw somewhere that use this method.
Coaxial cable for antenna TV (CATV) can also be useful for testing.
I think protect foil, the plastic housing, connected to GND, to ensure stability.
Not if necessary, worked for me in other MD.
Not how long would the AA batteries, in tehoria last longer than ordinary rechargeable batteries and are generally estimated at 10 Hs really do not know.
I wish you luck in trials
RegardsComment
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I used coaxial cable with BNC connector and mounted female connector on housing of MD.
Now testing possible power source placement. 8 AA pack (long one)
Housing for electronics is from soldering station.Comment
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I have assembled my detector with all components... it looks like it is whopper ... overweight class
I am already seeing back and hand pains
How much weight is your home made detector ?Comment
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Sorry for offtopic ... finished detector is 1.6 kg with battery pack.Comment
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Sdesic
No how heavy my detectors, make several, some AA rechargeable batteries.
Others like the Pulso Delta, lead gel batteries and go around her neck.
The Gel baterias, are low-priced and work very well, but they are heavy, I have one that I carry in the waist. The electronics along with the stick and coil.
For VLF detectors, a good option price and weight, can be cell batteries 3.6 volts for celulares.Comment
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Hi I Have Finish Surf Pi Long Board Version And It Working Nice But Why
my surf Pi Dont Detect Coin Just Detect Metal My Screw Driver OnlyComment
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Hi PakuOriginally posted by paku View Post
Nice to here you got your detector working.
Your problem may well be simple as adjustments in your delay settings
The best way to get maximum performance out of any PI detector not just the Surf is to adjust your Delay timing to a short time as possible while still been able to use the machine .
Only precision way is by using a scope but if you have not got one other option is trial and error using various coins or better still something thats pure gold as you can lay your hands on.
If your lucky and/or your coil build is of a high quality you may find you can set the delay to low to detect silver so in that situation adjust for a happy medium unless your only interested in gold
Hope this helps
RegardsComment
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ok i will try to set that delay
i will upload my video working surf pi long board detector
Thanks ALLComment
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Hi Everyone
Looks like Surf PI, was designed to work with low inductance coils, as seen in the following link:
http://www.geotech1.com/forums/showt...ematic&p=82315 # post82315 (post Nº"58")
The original coil consists of 20 turns of wire 0.5 mm and diameter of 23 cm., As mentioned by a forum member, which corresponds to about 250 uH, as MiSCeL calculator. This explains why the pulse width set by the R2 of 3.3 K is approximately 50 ns, so the first thing to evaluate is the coil, or try to get an original.
I'm using a 380 uH coil and get the most out extending the pulse width to about 100 ns.
Had problems of instability because of the telephone handset, which captures the emission coil is oriented according as, the solution was to use a piezoelectric handset.
Besides adding an R of 3.3 K between emitter and base of T1, 2N3906, for the reasons explained before, replace R20 47K by 22K to fix the threshold range. R18 remained in 47K.
Resistor R25 was adjusted to about 13K, through a preset delay and replaced by potentiometer 50K
With these values the minimum of delay setting corresponds to 15 ns, and the maximum at about 80 ns.
The PCB used was ApBerg.
It's all the changes you make, it's a nice and very sensitive detector.
JoséComment
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