Arduino Nano VLF Metal Detector Project - Main Discussion

[Qiaozhi]

I don't see any links to the source code for this project in the book or in this thread, am I just missing it somehow, or is everyone typing in the code from the book?

EDIT - never mind - it's in the Literature section of the forums...

Arduino Nano VLF Metal Detector Project - Published January 2024

[KRinAZ]

I don't see any links to the source code for this project in the book or in this thread, am I just missing it somehow, or is everyone typing in the code from the book?

EDIT - never mind - it's in the Literature section of the forums...

[Qiaozhi]

I think I'm going to build this, going to buy the book, I'm seeing copies of the book on eBay for less than the amazon.com price (which I'm assuming is the official source for the book) - is it possible this book is being pirated? Hope not, but...

I had a look on the UK eBay site, and they appear to be legitimate copies.
The Voodoo Project is also available using Expanded Distribution, which means you can also buy copies in a normal (or online) bookshop.
The prices on Amazon were actually cheaper than those on eBay.

Which Amazon site are you looking at?
If you have a link to a suspicious eBay sale, then please PM me the link.

[KRinAZ]

I think I'm going to build this, going to buy the book, I'm seeing copies of the book on eBay for less than the amazon.com price (which I'm assuming is the official source for the book) - is it possible this book is being pirated? Hope not, but...

[Qiaozhi]

Any chance the component list for this VLF detector list is available outside of the book? I don't have the VLF book yet, only the PI book and am currently building a purchase order for the PI components. I was hoping to buy enough extra components to also build the VLF at a later date and save a second shipping charge. I understand if it's being kept private but wanted to ask before I pull the trigger on my component order.

I've sent you a PM.
Note the errata at the bottom here -> https://www.geotech1.com/forums/foru...d-january-2024

[gdane]

Any chance the component list for this VLF detector list is available outside of the book? I don't have the VLF book yet, only the PI book and am currently building a purchase order for the PI components. I was hoping to buy enough extra components to also build the VLF at a later date and save a second shipping charge. I understand if it's being kept private but wanted to ask before I pull the trigger on my component order.

[KenS]

Hi, my LT1054s came from a fairly reliable UK supplier, cannot be sure they are genuine parts but pin 6 is 2.5V and free running (pin7 OC) they run around 25KHz, so definitely not ICL7660. Running the sync at 4 to 5KHz and feeding both oscillators via the single 20K resistor seems to upset these parts, since this usage is outside those defined on the datasheet its hard to know if the devices are substandard. I wonder if the grade/ESR of the capacitors is a contributing factor in this since I am not using Tantalum caps. I don't think free running at 25KHz will be a bad thing, so I am not going to get hung up on this, happy to leave pin 7 open and carry on. Thankyou.

[Op04]

ridiculous way would be using 5 watt qi wireless charging pad for watch and 2.5W receiver pad to get 5-+

[GeoMax]

Hi KenS,

if you purchased your LT1054 IC chips on eBay, Aliexpress or Alibaba, you can be sure (99%) you bought a fake IC from China. Only buy at trustet companies. Many local reseller buy in China as well and got cheated without knowing it.

[Qiaozhi]

I have also had problems with the -12V supplies. They were OK to the point of adding the demodulator, don't know if it was the time it had been powered or the incremental increase in load, but something had failed in U3 (LT1054) causing a low reference voltage, hence low amplitude osc signals on both U2 and U3. Using a new pair of LT1054s with their pin 7(Sync) bent out (i.e. removing the external sync), all ran normally again. Looking at the datasheet for LT1054, is the Sync pulse frequency from the Nano acceptable? Its running at 4.3KHz, which is much slower than the lowest recommended LT1054 frequency of 15KHz. Is this what is causing the problems with LT1054s?

Are you sure the LT1054s you're using are genuine parts?
Some people have found that they were re-labelled ICL7660s.
Of the many projects I have built using the LT1054, I have never encountered a problem.

[KenS]

I have also had problems with the -12V supplies. They were OK to the point of adding the demodulator, don't know if it was the time it had been powered or the incremental increase in load, but something had failed in U3 (LT1054) causing a low reference voltage, hence low amplitude osc signals on both U2 and U3. Using a new pair of LT1054s with their pin 7(Sync) bent out (i.e. removing the external sync), all ran normally again. Looking at the datasheet for LT1054, is the Sync pulse frequency from the Nano acceptable? Its running at 4.3KHz, which is much slower than the lowest recommended LT1054 frequency of 15KHz. Is this what is causing the problems with LT1054s?

[Qiaozhi]

TFT display 2.4 in 320x240 Where are the pins MOSI anf MISO I couldn't find it. Does anyone know where I can get it? Thanks

The pin mapping for the TFT is shown in Table 13-3 on page 107 of the book.

[fitos]

TFT display 2.4 in 320x240 Where are the pins MOSI anf MISO I couldn't find it. Does anyone know where I can get it? Thanks

[Qiaozhi]

I would think so but there is a risk. The ICL7660 is rated for 10V and the ICL7660a is rated for 12V. I have seen a 10V part run at 12V but it may become damaged over time if it is running hot.

I forgot to mention that.
Especially true since any fake ICs are probably sub-standard.

[Carl-NC]

you are right and that is why pulling up the osc line with a 5k resistor to +v works so do you think it will be fine to run it that way?

I would think so but there is a risk. The ICL7660 is rated for 10V and the ICL7660a is rated for 12V. I have seen a 10V part run at 12V but it may become damaged over time if it is running hot.