Superscan PI

[ZOUjiarui]

Correction: 3.9k and 15k are the sensitivity resistors. I don't know why the translation would link them to frequency.

[ZOUjiarui]

Hello everyone, after readjusting the equipment, it finally stabilized at 3.9kHz with medium sensitivity. However, at the highest sensitivity of 15kHz, it produced intermittent sound and couldn't stabilize. Finally, at medium sensitivity, the coil (25cm diameter, 500uH, 250ml Red Bull can) was tested at approximately 50cm. The depth was very similar to a normal pulse, and there was no noticeable difference at low power. It should perform even better with a larger coil.

[Goggy]

Hi All,

Think I messed up when doing the attachments earlier. The information for the SuperScan should be in the original post now. Oops,!

Regards,

Chris.

[ZOUjiarui]

Hi Goggy, it's a pleasure to see the original information. I will readjust the equipment according to the information you provided. Thank you so much!

[Goggy]

Hello ZOUjiarui & Co,

Think you may find this information useful if you have based your PCB on the original SuperScan.


SuperScan_Schematic.pdf

SuperScan_PCB _Set_Up.pdf

regards,

Chris.

[ZOUjiarui]

I apologize, I mistakenly treated both test points on the circuit diagram as delay channels. The correct test value for the second channel should be 1250µs with a pulse width of 45µs. Eric's original design specifies 1100µs.

[ZOUjiarui]

One thing I forgot to mention is that the original version used 0-ohm resistors for these jumpers, and the PCB retains the original design to the greatest extent possible.

[ZOUjiarui]

Hello, the PCB design wasn't mine. I've checked the circuit, and its layout is very close to the original layout in the KT315 data package. The circuit diagram is also fine, except that the 555 output power supply is missing a 1k resistor. The PCB has had the original version's testing protection resistor removed, and the ammeter area has also been omitted. The circuit itself is fine.

[GeoMax]

Hello,

The layout looks a bit odd. You're using wire jumpers on a 2-layer PCB when you could actually use traces. That doesn't make any sense at all. Is the layout based on the Superscan EM3 schematic? Or which schematic did you use to create the PCB?

[ZOUjiarui]

Use original chips

[ZOUjiarui]

Hello, after retesting, 86Hz, 500µs, pulse width, first sampling delay 150µs, sampling pulse width 45µs, everything is normal. Second sampling delay, there is no delay at all, and the sampling pulse width reaches 140µs. The PCB is exactly the same as the original, without any modifications.

[Goggy]

Hello all,

I am new to the forum, although experienced in the Superscan. How closely is this project board based upon the original Superscan?

I may be able to advise on some of the issues if closely enough related? Kind regards.

[ZOUjiarui]

It's a waste of effort. I don't know what secrets it has. The voltage is normal, 90Hz, and it can only be adjusted to half the normal pulse sensitivity at most. It's really useless.

[nasios]

I'm glad everything is going well!
The voltage on pin 6 must be negative (-4.35V), be careful with that! It cannot be positive.

Hi eduardo1979, i check the pin 6 from U1 555 253HZ and osc have this and U3, U4 4538 pin 6,7,9,70 have the osc 269Hz, and my pcb rospy have UA709 not the NE5534

[GeoMax]

Hi Geomax.
There is no specific reason, and I feel the same way you do. I simply drew the schematic based on the original PCB, which had been posted on the forum long before I started drafting the schematic myself. Since no schematic was available, I decided to draw one that matched the PCB layout, as I don't like building a detector blindly without understanding how the circuit works. That is simply why I decided to draw it. Furthermore, this circuit has plenty of room for improvement—especially the sampling integrator circuit, as well as the audio amplifier and VCO. I would also opt to add a unity-gain inverting amplifier after the preamplifier, remove the differential integrator, and replace it with a single-ended integrator. There are many things about this circuit that could be improved.

Hello Eduardo1979,

I agree with your comments. I, also would only start a PCB project if I had a schematic for it. However, since most free PCBs from the internet often contain errors, I prefer to create them myself. That way, I know for sure that they correspond to the schematic. And yes, the circuit has potential for improvement. But if you improve it too much, it's no longer the original circuit. If you want to improve every circuit stage, it's better to create a new design from scratch.