complete project

[mschmahl]

Hello Tinkerer,
can we go trough balance coil´s and settings for R27 and R28? The tinkerer_sb is on with permanent tone in headphones. It doesn´t show any reaction for metall. Here are some scope-shot´s.


I have built in the sn74hc4066n. On Pin 1 and 11 i see the same how on pin 6 from 2019 and on pin 13 and 12 i see the sample from pic. If i touch pin 2 or pin 10 with the scope-probe then the tone is changing higher or lower and one of the led´s glow.

[Tinkerer]

We need to go back to the balancing of the coils. Please see my post on IB coils.

Tinkerer

[Tinkerer]

Below is the LTSpice simulation file for the TX and target responses. With this you can see the differences that any change in Flayback capacitance or inductance causes.
You can also see what the different wave forms should look like.

For the induction balance, the important part to look at, is K3 L1 L3 0.25 this means that the surface area covered by the BU coil must be 0.25 times the surface area covered by the TX coil. Use medium coil thickness for the calculations.


Tinkerer

[mschmahl]

Thanks for this LTspice-file, tinkerer. I will try it tomorrow. So i hope to find my mistake.

[mschmahl]

Hi tinkerer,

i have a flyback now. The problem was the 6V supply for TC4452. Now i have 12V and all looks better.
Here are the pictures.


Thanks for your spice-simulation and your help.

[Tinkerer]

The first picture of the Flyback is good. Symmetric and no truncation.

On the second picture we see oscillations. Not good. Is this the STW18nm80 Mosfet?
Could it be that the power supply does not deliver enough current?
Normally the 2 large capacitors should supply all the current for the TX.

PS. on irfan, you can also rotate the pictures by a few degrees, best before cropping, and re-sample for smaller size.

[charleskerr]

Hi All
I've been following this thread off and on. Looks very interesting. I'm an electronics design engineer designing smd boards and use mainly pic processors, my design skills are a lot stronger than my programming skills. I have built silverdogs pi and but lost interest a while ago. I would be interested in doing an smd version of this board. Could someone please just summerise this design with a block diagram and post the pro's, con's and features. I think quite a few would be helped with this information. (How well would this work in water being a hybrid design)
Regards
Charles

[mschmahl]

@tinkerer
The first and the second picture are the same. Only the first with 2uS/div and the second with 10uS/div. It is done with the STW18nm80 but wired with cable clamp. I think too, that the current is to weak. What batteries did you use in your rig? Is there a possibility to check the current from this 2 capacitors? I have 2x 2200uF not 2x 4700uF how it is in the spice-simulation.
Thank´s a lot.

@charlesker
This design cries for a smd board especially the RX-Part. It would be very nice.
The Pro´s for me are: deep seeing with good sensitivity for small part´s and a possibility to distinguish between ferrous and non-ferrous.

[Tinkerer]

Hi All
I've been following this thread off and on. Looks very interesting. I'm an electronics design engineer designing smd boards and use mainly pic processors, my design skills are a lot stronger than my programming skills. I have built silverdogs pi and but lost interest a while ago. I would be interested in doing an smd version of this board. Could someone please just summerise this design with a block diagram and post the pro's, con's and features. I think quite a few would be helped with this information. (How well would this work in water being a hybrid design)
Regards
Charles

Charles,

your help will be most welcome.
For use in the water the non motion version might be better, but you could also try the motion version, changing the "Motion filter" for slower sweep speed.

If you want to get deeper involved, we could work on version 2, with a few improvements.
Also some programming help would be very welcome. I suggest we still keep the designs very simple, good for beginners. Later we can look at version 3, a bit more sophisticated, with full GB.

All the best

Tinkerer

[Tinkerer]

The problem with the TX could be:

We reduce the inrush current into the capacitors C13, C14, with R2, therefore we delay the capacitors from reaching their full voltage.
Switching the TX pulses on immediately, with a source that has a relative high internal resistance, does then not let the voltage reach full level for some time.

An initial delay in the timer will probably fix that.
An alternative solution would be to add a second switch to switch on the PIC timer after the rest of the circuit is powered up.

Tinkerer

[charleskerr]

Hi Tinkerer

Great! would it be possible to get a summary of the designs done so far and the sections done. I need to get an idea of where to start.
Basically a project roadmap.
BTW, any luck with your drive, in the last month I had 2 terabyte drives I bought just over a year ago (just out of warranty) doing the click dance.
All my data from the past 20 years is on them!!

Cheers
Charles

[satdaveuk]

Advanced hard drive recovery

Hi Tinkerer
If you still got problems recovering imformation from your hard drive I have a advanced industrial recovery tool that may well do the job.
Im not offering it as a open give away as I use it for work and it was very exspensive but if you want a copy and promise not to distribute it your welcome, just drop me a email.

Will be starting your project here really soon just need to finsh refitting the office so I have more room in the workshop because both are like a tip at the moment.

Warm regards

[Tinkerer]

The problem with the TX could be:

We reduce the inrush current into the capacitors C13, C14, with R2, therefore we delay the capacitors from reaching their full voltage.
Switching the TX pulses on immediately, with a source that has a relative high internal resistance, does then not let the voltage reach full level for some time.

An initial delay in the timer will probably fix that.
An alternative solution would be to add a second switch to switch on the PIC timer after the rest of the circuit is powered up.

Tinkerer

I simulated the delay. About 100ms should be fine. Got to change the PIC code for that now.

The simulation is really quite useful. Many things are so much easier to observe on the simulation than on the scope. I first made the real circuit, then tried to make a simulation that reproduces the results of the real circuit. The problem above, occurred because of subsequent changes, to improve details. It clearly shows that any change, anywhere in a circuit, causes possibly many subtle changes somewhere else in the circuit.

The more people tinkering with the design, the sooner we will have uncovered all possible problems.

Tinkerer

[Tinkerer]

Hi Tinkerer
If you still got problems recovering imformation from your hard drive I have a advanced industrial recovery tool that may well do the job.
Im not offering it as a open give away as I use it for work and it was very exspensive but if you want a copy and promise not to distribute it your welcome, just drop me a email.

Will be starting your project here really soon just need to finsh refitting the office so I have more room in the workshop because both are like a tip at the moment.

Warm regards

Thank you for the interest and the offer. I have packed and shipped the hard drive, together with half my electronics lab. In about 6 weeks I will unpack in my new home. At that time I will be very glad to accept your kind offer.

[Tinkerer]

Hi Tinkerer

Great! would it be possible to get a summary of the designs done so far and the sections done. I need to get an idea of where to start.
Basically a project roadmap.
BTW, any luck with your drive, in the last month I had 2 terabyte drives I bought just over a year ago (just out of warranty) doing the click dance.
All my data from the past 20 years is on them!!

Cheers
Charles

Here we are talking about the TINKERERS_SIMPLE_BASIC_MOTION (TINKERERS_SB_MO) design and the TINKERERS_SIMPLE_BASIC_NON-MOTION (TINKERERS_SB_NM).

The PSU is reduced to an absolute minimum for the sake of simplifying the design.

This simplified design uses only 2 samples, but a more complete design for version 2 will use several samples and DSP for GB etc.

These are simplified designs, mainly with the purpose to give people the opportunity to see the advantages and possible disadvantages of this method.

Although the TINKERERS TX waveform, at first sight, looks somewhat similar to the one of a traditional PI, it is actually very different.
There is high current running in the TX coil at all times. We can also sample the RX at all times.
The current remains in a resonant tank and therefore the power consumption is very low, relative to the high current of the TX transient.

The TX is bi-polar.

The combination of the very high power TX and the very high pulse repetition rate (PRR) give a good S/N and very good depth and sensitivity.

The downside is that all sorts of problems may still turn up, as seen above.

I have built some prototypes but not really field tested them.

Another problem is that my programming skills are about nil.

Any help is much appreciated.

Tinkerer