HAMMERHEAD REVISION D NEED ADVICE

[daverave]

Connect R7 to Q3-G for active pull-down. Offhand, I don't see a straightforward way to switch between vco & non-vco. It may be possible but would likely require some circuit changes.

- Carl

Hi Carl

on this revision D pcb do i need to short out R15/R8/R7 for the active pull down ?????

[Carl-NC]

Short R8 & R9 only. You may also need to remove D8 and finagle with the 555 timer components, it's been a Very Long Time since I've messed with this.

- Carl

[daverave]

Short R8 & R9 only. You may also need to remove D8 and finagle with the 555 timer components, it's been a Very Long Time since I've messed with this.

- Carl

Thanks Carl.

[g.s]

Good evening carl Thinking dealing with hammerhead .
am interested in modify for BIG OBJECTIVES, you believe that it can work in such situations (100 hz pulse)...


thanks in advance g.s

[Carl-NC]

Sure, you can easily take it down in pulse rate and even extend the pulse width. You may need to pay attention to thermal issues.

[g.s]

Congratulations on your work and the explanation you gave, what batteries can be used for this project ? , sla battery are suitable for a detector project ..which type battery has the lowest ohmic resistance ? .


sir carl a clearer pcb because one that I have is not city clean and I can not shed light purely will I have short circuit, I do not wish this to happen

[Carl-NC]

Lithium batteries have very low R, but if you use a low ESR cap on the transmitter then the battery R is not so important.

I don't understand your PCB concern... is it one you made yourself?

[g.s]

pcb is OK ...
I had concerns SOME CONCERNING THE line passing through your chip, appearance the film but is ok
So begins construction.
I hope to further analyze your plan.
you know carl I've learned quite a few things pi detectors,means from the forum here and congratulations for this drudge,When I read a circuit perceives HOW DOES the following steps ( power siplie,TX POWER,PULSE DELAY CIRCUIT,PREAMPLIFIER SAMPLING,FINAL STAGE SOUND.) They can not understand however the opamp, which in this case is ic8a and ic8b What exactly does the sampling signal Until I become voltage..
If we can help me on this I'll be grateful..
tenderers and my raki My production
.................

[g.s]

I just finished pcb your carl, and I find it quite stable YOU to tell you the truth do not expect to be stable... Good for you!....
concerning to the question that YOU he made about the (ic8a and ic8b ) aaaaaa converts the sampled signal into a square pulse, is what you YOU I say ???

...

[bernte_one]

where can i find latest layout for hamerhead with pic µ controller and hex code
still looking for some new projects

thanks for help

[kt315]

Hi Bern, a response is simple and you know else it. the book of George and Carl INSIDE THE METAL DETECTOR has all you need and ask.
have still questions? - write me in email.

[bernte_one]

ah thanks i supposed somethink like the hammerhead in the book found it already µcontrolled pi start at page 180 of the book

kind regards bernd