BANDIDO umax schematic / sensitivity

[mikael]

Hello,

I have made Carl's bandido II umax with the schematic. I can detect a 50eurocent at 20cm.
But how do you explain, that in same conditions, with the same coil i can detect the same 50eurocent coin at 31 cm ! with my silver sabre umax ?

The schematic seams to be comparable.

What could be the cause ?
I have no small audible noise when i turn the sensitivity at the max position. With the silver sabre, i can ear a small noise that indicates me that i am close to the floor.

Thanks for help.

What distance do you succeed to ear the first noise for a 50eurocent coin with the Bandido II ?

[Gene L.]

Re: BANDIDO umax schematic / sensitivity

You could be right!! Ill check the silver sabre schematic , "If I Still have It!". Maybe some other techs in the forum will say its better or at least as good as a Bandido,Using the same size coil Too! Thanks Gene L.

[mikael]

Re: BANDIDO umax schematic / sensitivity




I finally succeed in optimizing the bandido.
I obtain 30cm for a 50eurocent coin.
The problem was an oscillation of the beep :
When there was a beep, it created a current peak in the speaker. This peak created a parasitic beep and so on...
I increased the feed resistor of the speaker and uses an headphone and it is fixed !

cool !

I am trying now to root the schematic on a very small PCB with some components on both sides.