modification surfmaster pi

[giuseppem94]

time ago I built SurfMaster pi (not surfamster pi pro), turning the forum I Seen This diagram shows some changes, which are the benefits of making these changes? What sets the new trimmer 5k and 1k from what?
What does the word "127 OHIM piezo"?
http://img42.imageshack.us/img42/313...fschematic.jpg
there are changes better and at the same time easy to do?
thanks

[6666]

If you alter the value of the 3.3k resister
you can alter the pulse width
see pictures.

[giuseppem94]

thanks for the reply
what are the advantages?
what it means "127 OHIM piezo"?

[WM6]

what it means "127 OHIM piezo"?

It is not OHIM, but Ohms - mean loudspeaker of high (Ohms) impedance. Or you can use Piezo summer too instead.

[giuseppem94]

What changes, about the performance, if I change the pulse width?

[Sean_Goddard]

If you put an oscilloscope ACROSS the coil, you will actually be measuring the "equivalent" current through it (Ohms law?) So set the pulse widtch until the signal JUST starts to clip, at that point you know you have maximum current flow. Any more and you are just wasting battery power, any less and you are not developing the maximum field for your coil.

Optimising the PW in this way will give you best depth and best battery life (barring external factors not mentioned).

[6666]

Thanks for that tip Sean.

[andva]

Hi all!
I would like to build a low voltage warning light for my Surf machine. I use 10 pcs. of 1.2V 2100mAh AA cells. I thought of an easy circuit, for example when the voltage falls down to about 11V during operation, a red led would light. Can you show a circuit for it?
Thank you for your help!

[Altra]

Try google "low battery circuit image"

http://www.google.com/search?q=low+b...w=1069&bih=560

[Qiaozhi]

Hi all!
I would like to build a low voltage warning light for my Surf machine. I use 10 pcs. of 1.2V 2100mAh AA cells. I thought of an easy circuit, for example when the voltage falls down to about 11V during operation, a red led would light. Can you show a circuit for it?
Thank you for your help!

Have a look at the Hammerhead schematic. It uses a 12V battery supply, and has a simple low voltage warning light.
http://www.geotech1.com/pages/metdet...rhead/HHd1.pdf

[kt315]

Hi all!
I would like to build a low voltage warning light for my Surf machine. I use 10 pcs. of 1.2V 2100mAh AA cells. I thought of an easy circuit, for example when the voltage falls down to about 11V during operation, a red led would light. Can you show a circuit for it?
Thank you for your help!

[bravodenisu]

I have used this scheme!
http://electroschematics.com/wp-cont...er-Circuit.png
Only without the capacitor (C1)
It is simple and good!

[bernte_one]

what about a simple zenerdiode one resistor and a led?

[TH Jim]

In reply to the OP - the main difference between the pro and standard versions is that the adjustable delay on the standard surfpi has been replaced by adjustable gain on the pro model. I prefer the pro, the adjustable gain is much more useful to keep the machine stable in noisy environments, never found the adjustable delay to be of much use, i think it was just a marketing gimmick to sell a PI that had discrimination, it's not practicle to use it in the field.