Wombat Pulsed Oscillation

[Tec]

The ‘Wombat Pulsed Oscillation’ uses a mono coil and capacitor (tank circuit) oscillating freely, similar to a good old BFO or a ‘VLF’ detector.


Unlike a BFO or VLF detector, it uses a ‘time of flight’ chip, the TDC7200, to measure frequency and amplitude change with...

[stratiev_a]

Hi everyone,

I'm repairing an XP ADX 150 mainboard. The 10-pin IC located right next to the crystal , burned out after the coil cable was damaged.

The original IC markings are factory erased by XP.

Here are the PCB pin measurements without the IC installed:...

[Aziz]

Hi all,

found an interesting video from Woody:
https://www.youtube.com/watch?v=0GXx3ypgmqc


Aziz...

[cristiano.sar]

If we found the ideal damping resistor value with a damping tool and we could not find a resistor with that specific value in the market, is it better to put resistors in series or in parallel (with each other) to match the value?
For example, suppose my coil requires a damping resistor of 360R...

[moodz]

Aziz and myself have collaborated to bring you SPULE32 which is Aziz's coil modelling software.
He has kindly provided the original source code ( C, C++, ASM ) which originally was built for windows and I ( with AI help ) have ported to Javascript.
So to be clear Aziz did all the work and...

[Fadel saleh]

I have built a device equipped with an antenna. I used an Arduino, a control screen, and a single button. I also added external components: an LM386 amplifier IC, a BD139 transistor, and a 10k variable resistor, along with ceramic and disc capacitors. The setup relies on a ground connection (negative/earth)...

[Kevco]

I want to order some extra battery connectors that are used in the TDI, and connects to the Li-ion battery. Does anyone know the official part number, and manufacturer? Like Amphenol PC-1922993 (random junk as an example), or a Mouser P/N#?

I've tried all of the plug-in-the-wall power...

[Melano87]

Hi,
Since photos of the CS1220XD circuit board are never seen on the forum, here are some.
Regards...

[moodz]

I wanted a tool so I could look closely at the frontend of metal detector design. It turns out I had it on the bench right in front of me.

1. An FPGA board
2. A 24 bit ADC board.

BONUS .... No Soldering at all.

The hardware is about the same cost as a good...

[rwl518p]

Hi I know the EPE Resistivity Meter has a built in EPROM logger, but getting data out is a pretty hit and miss affair. Is it possible to add a USB data logger that writes to an SD Card?

[reetxeed]

Hi everyone! Has anyone tried building a VLF metal detector using a Teensy 4.1 microcontroller?
In my current circuit, the RX amplifier is an INA128U, the ADC is a 24-bit PCM1802, and it uses a Teensy 4.1 controller, a 240x240 pixel display, a rotary encoder, and a DRV8833-MD H-bridge module as...

[surf-tech]

Hello Geotech members,

I am considering building the Turkish Joker X1 Resistivity device and would appreciate feedback from anyone who has built or tested it. I am particularly interested in an independent assessment of its electronics, measurement accuracy, firmware, and overall engineering...

[Marchel]

A project for a multi-frequency metal detector recently appeared on GitHub, though it has not actually been built. The design is quite good, so I think it is worth taking a look at.

https://github.com/pingpongshow/MDX-1...

[Octopulse]

I have finally finished my overhaul of the Deepstar 1 detector. The detector now runs very well and the circuit feels more responsive and performance has increased.
I replaced all 12 electrolytic capacitors (as well as new potentiometers) which were now over 28 years old. Some older caps had leaked...

[dbanner]

This thread explores the method of tracking the target decay curve (pulse induction) by variation in time(dt).

It is entirely experimental, to test the method and to see how far it can be developed.

It is inspired by the PICKINI.

In a time-domain pulse induction...