ee teasure hunter

[Serafin]

Who are build the ee teasure hunter?.

I build and the max.deph in air was 50 cm is ok?
and a money 2p at 10 cm

[simeon webber]

Re: ee teasure hunter

sounds ok

i have 20 mhz and 4 mhz code for pic 16f84a that runs this one much better esp the 20 mhz
change the xtal and flash a compatable cpu {now only a few euros to buy 20 mhz speed}


i adjusted this way a long time ago but left it becouse the 10 mhz chips would have needed 2.5 nops to be added or make another nop loop for each nops added... to balance things.... so 20 mhz is more sutible speed

if others need the code{i send to a few along with a pcb design in 2 colours i made } i dont mind to post it
or perhaps carl can stick it with the rest of the bits for this one....


but your depth is a little low

first change the cpu then peek al parts and recheck your cap values and res decades {i do this all the time } use wrong decade esp with 5 band resisotors..

or a cap wrong type or way round

i recomend polyester layer for all and radial organic low res factor caps 105 deg c {not important ht variety}

use 1n4004 diodes in voltage pump

use 3300 cap not 1000uf cap in 9v rail main resoviour cap

place a diode from gnd to the +pumped rail cathode to the rail {to stabalise it use a 15v zener to clamp it }

the output of the pump is 15.5 and expects to be clamped hence the .5 volts extra above 15 by a 15 volt zener possible 1R res in series with the diode that supplies the rail from pin 6 on the pump also will help



i found using an lm318 isnt so good

first use lm3018 this is a far better version is cmos and uses less current

use low current 555 ic

make sure to use 74hct4066... or cd4066 *bp {must have buffers} {i use fets here instead of transistors to switch the stages }

for the other optimisations
the tl 072 use an op 02a or ne 5532

c10 and c11 change to 10 pf for 20 mhz xtals and 22pf anyway 33 is wrong and 33 is for 10 mhz {pic 84f standard}


the shunt rectifer diodes in4148 add ferrite beads too {3 mm long {or 5 } 2 mm dia
to each end of both

also add to the resistors 1w change too 2 watt carbon film ... and add again some beeds

to the center pin of your irf840ctf fet

r28 change to 22R + 22R in series .6 watt metal film or carbon ... is better but .6 watt


c15 changes to 100uf

i used a regulator small 78lm05 type to92 as a supply for the cpu
sounds overkill but why waist 1 % of 12V buring a resistor.... all the time
this made the cpu realy stable

appart from this

more like 20 - 40 cm with a {copper 2p or copper coin} in air is a good target
once tuned
the other side of the room waving it about should trigger it also {cuting flux}



also make sure to check which way you set the coil { i mean which conections to where } try the coil the other way round



email me for 20 mhz {very stable and a lot better} code or 4mhz code {what you expect from 4mhz}

[Serafin]

Re: ee teasure hunter

thanks simeon

[SIMEON WEBBER]

Re: ee teasure hunter

i have 8 mhz code for stuart pi 84 also {nice.....}