delta pulse more sensitive to gold delay reduced

[ossamaussama]

Hello Assama and Jose,

I finally found my problem. I have built Delta Pulse 2 Elbobaci design. After palyng around with many IC versions i found great stability from using HCF4066. The sound clicking from DP is verry nice and clean. Also the detection with 40 Cm coil is great. I can detect a bit biger helmet size target at 1,40 cm in the air. Coke of can 80 cm. Euro coin at 25 cm.Looks like is great for bigger objects. I did not play much with the settings.
I have built two coils of 1x1m.One of 12 turns and one of 16 turns using ADSL cable.
I am still looking for best sensitivity on using large coils.

Ossama and Jose ..you sugest on attaching a paralel 800 ohm resistor for each coil? What would be the R1,R5 and R6 in that case? I have R1 of 680k. Is that ok ?

Thanks for great help
Marius

dumping resistor R5

range from 680 to 1k for me for large coil (large coil dosnt work with low delay)

it affect on stability

that too much value of damping will make instability

very low value reduce sensitivity


fo large coil

it take longer time for flyback to decay and the automatic delay control in delta pulse

T2 an T3 will increase the delay

for that the large coil is less sensitive for small gold

i found that reduce the damping for large coil is better some time

but it depend in coil and how many turns

R6

affect on decaying carve and the LF357 gain

i think 1 k is better than 680
but you have to try in both cases


R1

this modification was done by KT315

and it was smart addition because R1 and c32 perform filtration and keep E- clean

many PI machine use this like deeper8 gold scan and pulse star


in pulse star c32 is 10.000 UF

so i change c32 to 10,000 and it give more stability and cleaner sound in speaker
R1=1,c32=10,000 uf





*- nice addition is to insert 20k or 50 k at the base of T7
this make threshold more accurate


with respect of HCF4066 is dont think it is better than cd4066 or mc14066 all of it works
nice

i think it was some noise in room


in my house there is noise during night i dont know the source may be electric line outside because i trun off all light but still


delta pulse haven't filter of such noise
i think use fixed frequency for delta pulse
and use active band base filter will give the best results


any way it is trying issue



regards

[ossamaussama]

hi every body

i make some circuit maker simulation on delta pulse in power supply section

see the photos

there is some noise in E-

R5 here is the battery internal resistance

assume good battery


test done on 100hz

c2 and c1 and c3 affect on noise level

but more value of C1 will give more time for voltage E- to rise up to -10.6

and the LM556 will have to voltage s

E+ and E+ so the output will be high and this will destroy the mosfet


see if change C1 TO 4700 U

[ossamaussama]

test with higher value

[Jose]

Hello Ossamaussama
Change the resistance of 6.8 K (R41) by 2.2 K. The result improved sensitivity and fast response.
I think this mod, can work in small coils of 28 cm or less.
I prefer to increase to 2.2 K R6, and not add the gain potentiometer 100 K.
This delay will have less time, provided you use a fast response coil.
It's just my opinion.
I'll try the scheme to reduce noise in the network.
Do you have any circuit "VCO NO" for the audio?, For the Delta Pulse.
Thanks a Greeting.

[Jose]

I think we should include the R buffer and the coil inductance value for the simulation.

[ossamaussama]

Hello Ossamaussama
Change the resistance of 6.8 K (R41) by 2.2 K. The result improved sensitivity and fast response.
I think this mod, can work in small coils of 28 cm or less.
I prefer to increase to 2.2 K R6, and not add the gain potentiometer 100 K.
This delay will have less time, provided you use a fast response coil.
It's just my opinion.
I'll try the scheme to reduce noise in the network.
Do you have any circuit "VCO NO" for the audio?, For the Delta Pulse.
Thanks a Greeting.

hi my friend



reduce noise by insert RC filter need specific frequency range

we may design band-pass active filter


take look at pulse star schematic they use RC filter


do you mean non VCO like that in surfmaster?

i didnot think it work nice with slow machine like delta pulse


and about the analysis by circuit maker it is power full software

and very accurate

there is noise in E-

may be this produce some instability when using 100 hz

didn't yet test with negative regulators that was add by KT315


***
what type of potentiometer used in manual tune is it normal or specific 10 turns ??



hope nice time

[pigeon]

nice work man

i use irf 840 instead of irf740

and insert 20k at base of T9

this make threshold more accurate

20K or 2K

[ossamaussama]

20K or 2K

see the photo

[ossamaussama]

see th effect of insert 20 k or 50 k

in vx which is pin7 of 555 timer VCO

when threshold in the lower setting (R3)

you didnot get the full voltage from V1( tr7)


*- R depend on meter for me i use 50k so i get full reading at low threshold

[pigeon]

Thank you very much for his efforts to improve the delta.

and I ask you kindly to improve the depth of the delta pulse with large coils.

please accept my best regards



PIGEON

[pigeon]

hi


Me I use the IRFP460. is it normal to make these changes


thank you

[ossamaussama]

IRF840:500 V 10 A
IRFP460:500 V 20A

yes it works

no difference


irf840 is better than irf740

need more operation voltage mosfet

that is better for flyback

[pigeon]

hi

what is necessary to put the 39 ohm resistor that connects the LM556 and irf740 and what is its role?

Me I use the IRFP460

thank you very much

[steaua581]

Hello Ossama and Jose

Is there a fix for the PULSE WIDE ...because when you increase pulse wide knob in delta pulse irf740 heats up really bad....if pulse wide is set up low is no problem...Why that happens?

regards
Marius

[Jose]

Hello Esteaua581 and Paloma
This is my experience:
Using ohms R39 protects IRF740 accidentally overheat, in some cases improves the shot.
For the TX pulse width, the coil solution is not less than 3 ohms and sink.
The pulse width works well between 125 and 200 usec.
125 usec for 400 to 600 Hz, 45X45 coils
200 usec to 100, 150 HZ, coils de1X1 mtrs.
With these values, TX stage remains cool or just warm.
The IRF840, runs cooler than the IRF740.
Regards