Detectors with led indicator lights

I was wondering how you would connect a led indicator light to the Mini pulse plus rev E and also the Baracuda rev A which is my next project how would you go about this as i have seen some detectors with led lights don't know if you can use them together or chose between sound or flashing led. also seen a video that suggected a more oval shape coil works better than a round one is this the case with MPP and Baracuda or is this more for vlf type detectors .
Graham

[Carl-NC]

Most PI detectors have a final gain stage before the audio that produces a raw voltage based on signal level. In the MPP it is U4, in the Barracuda it is U7. It appears with both that a target causes a rising voltage but that's just at a glance. If so, probably something as simple as an NPN diffpair would do the job. One base to the opamp output, the other base to an adjustable voltage so you can set the LED turn-on threshold. The emitter resistor sets the LED current.

Keep in mind that if you are going to use the LED as a primary indicator (such as for diving) you will lose a lot of sensitivity. It's the same as running the audio threshold to a "silent search" level.

[Op04]

I was wondering how you would connect a led indicator light to the Mini pulse plus rev E and also the Baracuda rev A which is my next project how would you go about this as i have seen some detectors with led lights don't know if you can use them together or chose between sound or flashing led. also seen a video that suggected a more oval shape coil works better than a round one is this the case with MPP and Baracuda or is this more for vlf type detectors .
Graham

Need experiment, try separate battery to supply led vu meter for audio which is ready made available, connect to output speaker but not sharing the same power supply of MPP/any detector

[Graham]

Thankyou for the info help about leds. for detectors . Sleeping on detector ideas thought if you got 2 thin kitchen cutting boards hard plastic type and had a copping saw or gig saw you could cut them to shape round or oval and sandwich detector coil between them and silicone around the edge should be fairly light and drill hole for coax cable just a thought. Graham