Pulse Star II (first analog version)

[kt315]

Oh... the Pulse Star II detects a Coca-Cola can at 1,3m only? I expected much more.

cola can is small target for 1x1 frame coil so do not wait good depth. normal-standart one is steel Wehrmacht helmet. it's good for the test on depth.

[Orbit]

Here is a photo of the original pcb motherboard where most of the ic components can be clearly identified..

[Jose]

Thanks, Orbita. The module I purchased is working fine with the LF444 instead of the TL064CN. I can't get the reset to retain the audio threshold when approaching bricks or iron pliers. Various TL064Ns and other CA3130s have been tested; I don't know if these last ones are counterfeit.
The detector is sensitive and stable; the power consumption without the discrimination module is low, around 105 mA.
I would like to modify the TX pulse width to obtain greater depth. Perhaps the 4022 can be reconfigured.

[Orbit]

Thanks, Orbita. The module I purchased is working fine with the LF444 instead of the TL064CN. I can't get the reset to retain the audio threshold when approaching bricks or iron pliers. Various TL064Ns and other CA3130s have been tested; I don't know if these last ones are counterfeit.
The detector is sensitive and stable; the power consumption without the discrimination module is low, around 105 mA.
I would like to modify the TX pulse width to obtain greater depth. Perhaps the 4022 can be reconfigured.

Pay attention to the components marked in red, the pulse width can be increased by replacing 1nf with 1.4nf from 100us to 150us.

[Jose]

I've been running some tests. The 200k and 82k resistors and the 1.2nF capacitor near the 4022 IC set the initial and final sampling times, as well as the transmission pulse width. They also influence the delay.
I replaced the 82k resistor with a 130k resistor, and the transmission pulse width was adjusted to 200us without affecting the other parameters.
Current consumption increased from 105mA to 185mA.
Air tests show an improvement in detection distance; this remains to be tested in the field.

[Orbit]

Hi Jose, believe it or not, I have a project from before, I don't remember exactly, but about ten years and maybe more during that time I made one device for myself, one I gave as a gift and another that I also gave to the man who gave me the first module, so a total of 3 devices. As I may be here on this thread or somewhere on another thread I wanted to respect the author and I didn't want to sell the whole project was just put aside. I was asked by many, among others, and some from Bulgaria to be involved in this topic, I simply did not want to out of respect for the author.. You know how it went on!!! So I paid almost no attention to this project for many years, I am presenting what I wrote down and tried a long time ago, but I was not occupied much with this project.Now everything is here that the hobbyists wanted, and I believe also the producers from Bulgaria who supposedly invent projects from their heads without ever having attended geotech in their life.

[algan]

I've been running some tests. The 200k and 82k resistors and the 1.2nF capacitor near the 4022 IC set the initial and final sampling times, as well as the transmission pulse width. They also influence the delay.
I replaced the 82k resistor with a 130k resistor, and the transmission pulse width was adjusted to 200us without affecting the other parameters.
Current consumption increased from 105mA to 185mA.
Air tests show an improvement in detection distance; this remains to be tested in the field.

Hi Jose, can you tell me how your test with air on a Coca-Cola can with your antenna is, but tell me what size is your antenna? I will try changing the resistor and test if it affects the depth.

[Jose]

Hi Orbita, I don't doubt what you're saying. I appreciate your work; thanks to them and other forum members, we now have all the information about the PS2.
Algan, my coil is 45 cm in diameter and has an inductance of 660 uH. I tried a 470 uH coil and an 880 uH coil, but they didn't work well.
It's essential to correctly adjust the damping resistance.
The distance to the 475 cm³ soda can is 100 to 110 cm. There's a slight improvement when increasing the transmit pulse width to 200 us, but I don't know if it's really worth it, because it also increases the consumption, from 105 to 185 mA.
The good thing is that we can experiment with the TX width without affecting the other parameters.

[algan]

Yes, Jose, we can experiment. My suggestion for an experiment is, for example, without changing the resistors you mentioned, but by changing only the quartz instead of 2.5 MHz, to test at 3 MHz. Then the frequency will increase, maybe to 700 hertz, and with that the pulse width will also increase, but I can't say by how much, maybe between 110 us or 120 us, I don't know exactly, I haven't done it, but I can't say whether it will affect the depth.