delta pulse more sensitive to gold delay reduced

[ossamaussama]

i study delta pulse schematic very well and test every part

i can say it is powerful design and lazy deep detector
give sound when metal present and give sound when re tune

its design seem to be strange not like others hummer head deeper 8 gold scan

and they use integrator with diode !!!

more frequency make fast re tune because of bilateral switch connected to tr2

T4 T6 T7 transistor configured as diode

T5 used to give -.7 initial volt to start the integrator
be turn on D13
note that
D13 WITH 56K
and D12 in reverse with 5k
this integrator design to hold output positive longer time than negative


if we take look to pulse star schematic

we see capacitor 10,000 uf in c32

this reduce the effect of TX circuit on receiver circuit

i will post practical video later

regards

[bernte_one]

photos

hello to all which has build delta pulse here
im short before finishing
and would compare to others who have build it
so plaese- some photos were nice

regards

and video links too :-)

[Jose]

This is my experience with the "DP".
As stated Ossamaussama, DP is slow to react, this occurs with frequency 300 Hz, from 550 to 650 Hz this improvement effect.
It also seems improvement with the addition of the diode between the IRF740 and coil, and adding a circuit between the 556 and shoot the IRF740, you can even experiment with an R of 20 to 100 ohms.
All these changes together, improving the response of DP. (at least this happens in my DP)
regards
Jose

[pigeon]

hi Jose


can you put pictures on the changes you have made


thank you

best regards

P.

[Jose]

Hello Paloma
Changes in red
Diode between IRF740 and coil. Retrieved TV chassis
After I put the trigger circuit.
Greetings Jose

[Jose]

Shot circuit 4427.

R buffer (R5). Adjusted according to the coil

[ossamaussama]

Shot circuit 4427.

R buffer (R5). Adjusted according to the coil

nice work man

i use irf 840 instead of irf740

and insert 20k at base of T9

this make threshold more accurate

[ossamaussama]

useful modifications

hi to all

i found increasing the value of c32 from 4700 uf to 10,000uf give more stability

this capacitor reduce the effect of voltage variations
on E+and E-
because of TX time

second thing is that P5 threshold performance can be more better when inserting a resistor 25 k up to 33 k
useful modifications

because at low the resold current will pass to the ground more than to the 555 VCO


and make loading effect on the output of integrator




see the photo

[Jose]

A photo at the request of Bernte_one

[ossamaussama]

hi jose

what type of battery ? lithium ion 1.5v or nickel–cadmium 1.2v

i use lead acid which is heavy cheap battery

12 volts 4.5 amps

[Jose]

Hi Ossamausama
They are nickel cadmium for home use, 1.2 volts. I use them for space reasons.
I deem the Gel, because they are cheap and work well.
Jose

[ossamaussama]

HI jose

after some experiments

change the following and you will get very good stability

c32 to 10,000 uf

it is more important than c31 and c30

use c30 4700uf
it is enough

second note


R28 IS 56 K

change it to 80k or more the device will be more slower but stable

and no change in detection

and put 50 k series with T9 base

[Jose]

Thanks ossamaosumma
I will test the new changes and then will discuss the results
Jose

[ossamaussama]

i test it today with large coil

yes it is more stable but not working in low delay ( depth killed) if i use low delay in large coil


dont know why

may be saturation problem

any why forget about r28 keep it as it 56k

[steaua581]

Delta pulse

Hello Ossama and Jose

I have built 2 units but in both cases i don"t get really good stability and depth.Probably i made them with no oscoloscope...and meaby i am testing them inside the house with lots of powerlines.
I"ve got confused from seen so many schematics and versions of this unit. Some have the high speed diode..some dont have it...the specifications were not clear for the precision electronic parts and key elements on circuit.
I was wonderig for a wile now ..and since i am not an expert this though keeps on coming..can we ad to Delta Pulse a VISUAL TARGET ANALIZER? such a small mini osciloscope where we can decide wich type of metal is under the coil by reading the curve on the osciloscope display? Is that hard to make?
I think that Delta Pulse can be a lot better ...
Also having a new revised parts optimised for large coil use and also the set-up for small coil... I am thinking to take to a separate pcb R5,R6, R1 etc... and use a swich for best setup on 1x1 and smaller 20 cm coil...wont be that a better choice to use DP for small and large objects with the help of a swich?

Thanx
Regards
Marius