Arduino Nano PI Main Discussion

[dingbatca]

MartinB. My coil wrapping jig is just a simple pattern cut out with my CNC. I designed and 3D printed the pegs as part of the jig. My 6yr old daughter picked the peg color. Some fun pic's attached.

[MartinB]

Thanks,
It seems that these problems are due to the fact that my book has not been received.

Take a look at Surfdetectors series of videos on YouTube. Very helpful.

[MartinB]

I am happy to report I got my Nano PI running!

Now I am off trying to build a higher performance coil. I have the fast coil article that I have read through multiple time. I started off with a basic round coil, per the book. Then built two elliptical coils, and lastly I tried my hand at making a basic basket coil. Got the basket correct on the secound try. But none of these seem to respond all that much faster. All my coils are right around 18~20uS response time. I have always aimed for the same specs 300~400uH, and I have hit that range every time. Using a spool of 26awg magnet/speaker wire. I know Teflon insulation should help, but I am currently working with what I have. Happy to invest in the better wire, once I have the basic coil building technique hammered out.

Any advice to improve response time?

Pics attached.

That is a pretty cool coil jig you have there. What are the plastic pegs?

[dingbatca]

Good to know. I will hijack the Voodoo's TX and pre-amp circuit and jumper it into a Nano PI and see what I come up with.

[waltr]

Fascinating, from a relative newbie, such as myself.

I hooked my same coils up to the Voodoo and found most of my coils were around 13~20uS. But the basket came in at solid 9uS! That scoots!!

Jumping WAY off the deep end. Could I borrow the TX and pre-amp circuit from the Voodoo, and replace them on the Nano PI (on a proto board)? Frankenstein PI?

Good trying the VooDoo with a 2 stage pre-amp. 9us is good. On my HH2 I was able to get an IB DD coil down to about 11us using a single NE5534 pre-amp.

Yes, you can use the VooDoo pre-amp on this Nano project. You may need to adjust gains but this is easy.
George did this Nano project simply for everyone to get started using a processor and experimenting. He didn't do much with the analog circuits.

[dingbatca]

Fascinating, from a relative newbie, such as myself.

I hooked my same coils up to the Voodoo and found most of my coils were around 13~20uS. But the basket came in at solid 9uS! That scoots!!

Jumping WAY off the deep end. Could I borrow the TX and pre-amp circuit from the Voodoo, and replace them on the Nano PI (on a proto board)? Frankenstein PI?

[waltr]

I am happy to report I got my Nano PI running!

Now I am off trying to build a higher performance coil. I have the fast coil article that I have read through multiple time. I started off with a basic round coil, per the book. Then built two elliptical coils, and lastly I tried my hand at making a basic basket coil. Got the basket correct on the secound try. But none of these seem to respond all that much faster. All my coils are right around 18~20uS response time. I have always aimed for the same specs 300~400uH, and I have hit that range every time. Using a spool of 26awg magnet/speaker wire. I know Teflon insulation should help, but I am currently working with what I have. Happy to invest in the better wire, once I have the basic coil building technique hammered out.

Any advice to improve response time?

Pics attached.

That looks like the pre-amp recovery time. The NE5534 is not known to recover from output overloads very quick.
This subject has many threads and some solutions that improve pre-amp recovery time. The most common is a two stage pre-amp.

[dingbatca]

I am happy to report I got my Nano PI running!

Now I am off trying to build a higher performance coil. I have the fast coil article that I have read through multiple time. I started off with a basic round coil, per the book. Then built two elliptical coils, and lastly I tried my hand at making a basic basket coil. Got the basket correct on the secound try. But none of these seem to respond all that much faster. All my coils are right around 18~20uS response time. I have always aimed for the same specs 300~400uH, and I have hit that range every time. Using a spool of 26awg magnet/speaker wire. I know Teflon insulation should help, but I am currently working with what I have. Happy to invest in the better wire, once I have the basic coil building technique hammered out.

Any advice to improve response time?

Pics attached.

[lc516]

There is an order status button on the Book Depository website, where you can enter your order number and email address.
It looks like you are classed as "Rest of the World", which should take 20-30 business days.
https://www.bookdepository.com

YES,I got it through google that it take about 30 days to receive the book.
I'm not impatient now,and I blieve I can learn more through the book by then.
Thanks!

[Qiaozhi]

Thanks,
It seems that these problems are due to the fact that my book has not been received.

There is an order status button on the Book Depository website, where you can enter your order number and email address.
It looks like you are classed as "Rest of the World", which should take 20-30 business days.

https://www.bookdepository.com

[lc516]

Fig. 4-14 shows the correct position for the main sample pulse relative to the preamp output. If you set the sample delay to start before this point, then the preamp output will either be in saturation or close to it. This causes the audio to sound "abnormal". In fact, this is one method of finding the correct sample position. Start with the sample delay pot set to minimum, and then increase the delay until the audio sounds stable. The minimum sample point is dependent on coil you have connected.

Thanks,
It seems that these problems are due to the fact that my book has not been received.

[Qiaozhi]

When I set mainSample to be less than 30us(sampleing starts when the slop of preamp is high), I got this waveform on TP11

[ATTACH]55039[/ATTACH]

This makes the audio output abnormal.
Is that because the capacitance on OPA?

Fig. 4-14 shows the correct position for the main sample pulse relative to the preamp output. If you set the sample delay to start before this point, then the preamp output will either be in saturation or close to it. This causes the audio to sound "abnormal". In fact, this is one method of finding the correct sample position. Start with the sample delay pot set to minimum, and then increase the delay until the audio sounds stable. The minimum sample point is dependent on coil you have connected.

[lc516]

When I set mainSample to be less than 30us(sampleing starts when the slop of preamp is high), I got this waveform on TP11



This makes the audio output abnormal.
Is that because the capacitance on OPA?

[lc516]

It depends on the battery pack used. If you make R20 too low a value, it could potentially cause a voltage drop at the input.
Anyway, you could always try it and find out the answer yourself. It won't break anything.

I have replaced R20 to 47 ohm,it looks work OK,This is to increase the volume of speacker.

Thank you for the information.

[Qiaozhi]

Hi,Qiaozhi

I tried to lower R20 to 30ohm,will that get noice on the circuit?

It depends on the battery pack used. If you make R20 too low a value, it could potentially cause a voltage drop at the input.
Anyway, you could always try it and find out the answer yourself. It won't break anything.