Arduino Nano VLF Metal Detector Project - Main Discussion

[Qiaozhi]

This is the main discussion area for the project.

The introduction is here -> Arduino Nano VLF Metal Detector Project - Published January 2024

[Olly]

Excellent stuff George, my book is on order and eagerly awaited.

[ArchibaldSTM]

Interesting.. We will follow the development of the project. Thank you!

[GeoMax]

Hi Qiaozhi,
nice project... just purchased a copy of the book on Amazon....

[ivconic]

[ivconic]

Very interesting, neat, likeable!
I am interested in one thing; why did you decide to generate the sine signal from the MCU directly?
In this way, you took even 8 pins!
Among them is a UART port as well as some very useful PWM pins.
Some are directly tied and controlled by timers.
Too many resources wasted. Hence the two Nanos.
I'm not saying it's bad, it can be done that way too, why not.
I'm just wondering why you didn't just use one PWM pin and still shape it with a discrete solution out of MCU.
Even more; wouldn't it be interesting to drive the TX directly with a square signal?
So much for now, I didn't get to analyze everything.
But you certainly gave a very good starting point for upgrades!
Great idea!

[Qiaozhi]

Very interesting, neat, likeable!
I am interested in one thing; why did you decide to generate the sine signal from the MCU directly?
In this way, you took even 8 pins!
Among them is a UART port as well as some very useful PWM pins.
Some are directly tied and controlled by timers.
Too many resources wasted. Hence the two Nanos.
I'm not saying it's bad, it can be done that way too, why not.
I'm just wondering why you didn't just use one PWM pin and still shape it with a discrete solution out of MCU.
Even more; wouldn't it be interesting to drive the TX directly with a square signal?
So much for now, I didn't get to analyze everything.
But you certainly gave a very good starting point for upgrades!
Great idea!

I actually discuss those points in the book.

[ivconic]

[Olly]

Got my book this morning, very nice indeed.
I particularly like the flexibility achieved by using the R-2R DAC driver for the TX.

[Qiaozhi]

Got my book this morning, very nice indeed.
I particularly like the flexibility achieved by using the R-2R DAC driver for the TX.

Thanks Olly.
Glad you like it.

[ivconic]

One of the ideas that comes to my mind is the use of a mux circuit in sine wave generation.
Of course, that part of the code will undergo major changes.
With just 5 random pins you expand to 16 channels.

[turboaleks]

There is a little mistake on page 134. In the 10k listing the last resistor should be R70 (not R79).

[Qiaozhi]

There is a little mistake on page 134. In the 10k listing the last resistor should be R70 (not R79).

Thanks.
I've add that to the Errata section -> Arduino Nano VLF Metal Detector Project - Published January 2024

[Goaty]

Also, 2 X LT1054 (U2 & U3) missing from IC s on p133

[Qiaozhi]

Also, 2 X LT1054 (U2 & U3) missing from IC s on p133

Thanks ... added to errata list -> Arduino Nano VLF Metal Detector Project - Published January 2024
It doesn't matter how many times you read through the text, there's always some pesky errors that slip through.