Updated Mirage PI (Ex Hammerhead)- Mono Coil, DD Coil or Super D Coil Options

[GeoMax]

Hi Hesam_k69,

here some thoughts about your "great TL12000 device". I drew the schematic from several hand drawings last year to see whether it would be good to make a PCB out of it. But after drawing it, I saw that it is more or less only a simple PI. There are much better detector...

[Emersonpaz]

I made the project VCO from mickstv I'm using it on the Polish pi https://youtu.be/RDV93ZdeGhk

[moodz]

Thanks waltr ....

Attached is the source code ....

Theres stuff in there to do LCD / Serial and Rotary Encoder .... WIP.

The timing is set up for a 30us TX followed by a 30us RX. Why 30us ? ... because otherwise the TX fet will approach avalanche and the linear...

[Elliot]

Updated version of the TreasureLinx Mirage Pulse Induction Detector.
It's been about 40 years since I first started detecting. I also worked on making some detectors way back then - e.g. ETI 1500 and the Sandbank PI. I even used to review some early Minelab detectors for Miners Den in Victoria,...

[aulook]

Hello Guys. I have a delta pulse PI metal detector and have been using it for years. Its audio seems annoying to my ears. I want to modify it's audio stage by changing the 555 audio driver to cd4046 vco ic that will sound like the pulse star. Is this possible? Does anybody has the wiring diagram? Any...

[ivconic]

This could be used as nice audio vco for various projects, of course; suitable for PI detectors.
There are two versions of hex that i prepared; 0v to 5v at the input and 5v to 0v at the input.
Most of the diy PI's we have here on forum will be matched with second; the 5v to 0v at the input...

[6666]

I found this Surf PI mod in my collection of PI mods.

It gives the option of VCO audio, which could be handy if experimenting with TX PPS.

I dont know where it came from and there is no name on it, but could be useful....

[dgm]

Good morning to all the members of this Forum, I wanted to ask if it was possible to have information on the connections, to change the audio to the surf PI 1.2 purchased from the silver dog, with a VCO circuit. I searched the forum but found nothing interesting. Thank you for those who can give me...

[Riss]

#26 Thank you very much for your attention !!! Sherlock Holmes is one beginner amateur compared to you! - This is my very old prototype developed 2013 year . Ordinary PI . Nothing special . It was made with old parts from the garbage - scrap . In the old parts is hidden creative...

[qute1]

No i wouldn't do it on pi pro as subtly different but it works fine on surfpi longboards i have it on 3 now it just changes nuuurrrr sound to peeeuuu ie the tone rises as the object comes closer to the coil instead of nuuurrr (which really gets on your wick after a while)......
i wouldn't say...

[qute1]

Sorry thought i had covered that with the quote.....:

"Cheapest way to make VCO in Surf PI was to connect pin 5 of 555 chip with pin 7 of LM358 by resistor or capacitor in the original Surf PI schematic. Such trick will let your detector to change frequency of pulses as well as sound...

[Qiaozhi]

U1 (555) is the TX oscillator. You could change R1 (100k) to 180k, and R2 (3k3) to 22k. This will give you a TX pulse width of 332us and a transmit rate of 329pps. Alternatively, replace R1 and R2 with trimmers, and adjust the values to get exactly what you want. However, the Surf-PI also uses the TX...

[daverave]

i did try some caps on the +5v/-5v lines for the vco pcb but made no difference...i cannot understand why a pulsescan board would have this problem being a commercial detector...i wonder how whites got around this problem in their later detectors...the hammerhead design has the same problem but i never...

[dbanner]

My advice is to build all of them and have fun along the way. After which you will become expert in pi detectors. You must have oscilloscope, otherwise you are like blind man at a market in Kandahar. Mini pulse is very good. The revision E would benefit from upgraded vco. Special attention must go into...

[waltr]

re-do of mods
The Mods in Post #70 were not the best. At first it seemed the sensitivity was still good but it was not.
I put the Gain stages after the JFET switches back in and then decreased the gain in the SAT stage (external pot). I found that in electrically noise areas the SAT gain...

[waltr]

20cm (8") Concentric coil

This is another type of Induction Balance coil consisting of an outer TX coil and an inner RX coil. The IB is achieved by winding a few turns of the TX around the RX coil but in the opposite direction. This Balances or Nulls the TX magnetic field in the...

[waltr]

New PIC code
A few changes to the PIC code include:


Added a variable delay to the PPS time to avoid interference. Used ADC 2 and made the TX pulse length fixed at 100usec. I was having low frequency wobbles at the SAT output at times. Did notice that when I changes the PPS...

[geoscash1]

Well, finally decided to build this project, something I bought quite sometime ago but never got to it because I just didnt have the knowledge when I got it. I now understand the components better, how the pi operates and have a better understanding of using my scope so decided its time to build the...

[daverave]

Have you done any experimenting with this circuit ???? my brain the same cannot process too much information...i just do things by trial and error...i did once modify a hammer head circuit so the vco worked at much higher frequency ins tead of click click and i included also amplitude as...

[ivconic]

NRF24L01 is very good solution for that. After the setting active RX/TX mode (120-130uS) packets are transmitted somewhat bellow 1mS.
Quite good for wireless headphones and similar applications.
But it's just plain data TX/RX. You'll have to figure out how to make raw audio from that....

[dfbowers]

Pin 7 would be the input to the audio stage - a fluctuating D.C. signal that would normally go to a 555 timer configured as a VCO. The switch would be used for a threshold audio like the Baracuda or Surf PI, or a threshold + VCO. The circuit I use it in is very similar to the Hammerhead.
Do...

[Orbit]

Whether they are of depth with included channel two or with one channel ? With one channel and coil 11inches I have a similar range in my pi detector with vco with one channel ....

[douglas]

I love the surf PI that I built on the longboard, but the pitch coming out of the phones drive me crazy. As a matter of fact I have altered the tone on my white's detectors sop that it is a lower frequency. How do you do this to the surf PI in the Non VCO version?

[ionut_mtb]

so baracuda is motion detector only? (same like surf pi?) does anyone mod vco for bara? is possible to take the HH vco to implement in bara?...

[ionut_mtb]

Can you compare both pi and vlf detectors? Only people who used both for saltwater wet beach and underwater ? What isyour oppinion about xp deus in these circumstances compared to PI. Are u using only vco? I have a surf pi pro but never used in the beach because is forbiden in my country. It goes to...