XP Deus 2 Transmit frequencies

[Carl-NC]

No, you can only measure field strength. The probe can be calibrated to measure absolute field strength in Teslas and this can be used to calculate the ampere-turns, but not the amperes or the turns.

[Altra]

Hi Carl, I can see in your circuit a lot of attention to precision. Are you able make actual current measurements? If so, do you need a fixture to hold the tx coil and sensor at some fixed orientation and spacing? Thanks for posting these circuits.

[Carl-NC]

It's a damping resistor to tame unintended oscillations. I use 1k.

[JoyJo]

What is the significance of the RD resistor?

[Carl-NC]

The inductor has a ferrite core and, yes, if you get it too close to the coil the detector might overload. That doesn't alter the TX signal, tho.

[Mark-VA]

For detector fields you don't need to go that low. Here is the (more) complete circuitry for my field probe:


For the sensor, I use a Wurth 7447480331 which has L = 330uH and R = 0.3Ω, or a tau of 1100us. This is plenty low enough (145Hz) for detectors. Here is the measured field for a Vanquish 540:



The slight bowing you see in the B-field waveform is due to the resistance of the Vanquish's TX coil, which has a tau of 260us.

ITMD-3 Appendix A will give all the details for this probe. Soon.

Does the lead core of the Wurth 7447480331cause the detector to detect an overload?

For the sensor, I use a Wurth 7447480331 which has L = 330uH and R = 0.3Ω, or a tau of 1100us.

[Marchel]

Then you are likely to write original software. the goal is more coins in the pocket.

It took me a lot of time and attempts to build a functional metal detector that still needs to be developed.

[Riss]

Then you are likely to write original software. the goal is more coins in the pocket.

[Marchel]

Marchel , you probably you understand from software - are you good at programming? how many years of experience do you have with detectors - in the field?

I'm not that good at programming because I'm just self-taught, but I've been working with metal detectors for about 15 years.

[Riss]

My project is based on the STM32H7 processor and, unlike the XP Deus, does not have an external ADC but uses an internal 16bit ADC. Here are my final PCBs which still contain small errors. I am testing the project on the original coil X35 22cm, if anyone is interested in working together on this project, we can create a special contribution on this forum.

Marchel , you probably you understand from software - are you good at programming? how many years of experience do you have with detectors - in the field?

[Riss]

ok

[Riss]

Excellent I don't have an operational amplifier with such datasheet . it's a real beast,

[Carl-NC]

Just having the inductor for the sensor by itself will distort the flat frequency response if the TIA.The input impedance must be loaded up to preserve low frequency response. Eg for 20 hz to 150 khz see below ...

For detector fields you don't need to go that low. Here is the (more) complete circuitry for my field probe:


For the sensor, I use a Wurth 7447480331 which has L = 330uH and R = 0.3Ω, or a tau of 1100us. This is plenty low enough (145Hz) for detectors. Here is the measured field for a Vanquish 540:



The slight bowing you see in the B-field waveform is due to the resistance of the Vanquish's TX coil, which has a tau of 260us.

ITMD-3 Appendix A will give all the details for this probe. Soon.

[Altra]

Thanks that's some good information. When I get some time, I try your circuit.

[moodz]

Hi Riss, I think you are confused. This is a non contact, transformer-less oscilloscope probe. It's for relative visualization of the coil current. Carl posted the idea above, which I have never seen before. Maybe he can explain it. All I know is it works!

Just having the inductor for the sensor by itself will distort the flat frequency response if the TIA.The input impedance must be loaded up to preserve low frequency response. Eg for 20 hz to 150 khz see below ...