Arduino Nano PI Main Discussion

[Agme]

Hi Agme
The issue you are having with 3/4 display is that the starting point is not at the left hand side of the display
Have you got a line in your code that looks something like this?
U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); which is used to initialise the display.
To select the right statement for your display, go into the U8glib folder, select the .scr file and open with Notepad++ which is downloadable from https://notepad.software/download
Find the right statement for your display and then copy and paste into your code. Just be aware that there are hundreds of line entries in the .scr file so this might take a bit of time

Thanks, I will try it. I spent so much time reading peoples code and datasheet for this display I think I understand the commands to directly control it without the libraries. I have been trying to get it to be as fast and small as possible and it seems difficult to do with the libraries.

[MartinB]

I attempted to make the display work with the onboard nano. It worked but it was not behaving normal there was jitter in the pulses. And i think some of the analog readings where dropping out. I think i will see if i can use a Attiny chip or something that requires less power to read and display the readings from the board.

I was unable to get the U8x8lib to work with my display. It would only show a 3/4 of the screen.
I found a very small code that might work, but i did not try on the onboard nano yet.
http://www.technoblogy.com/show?23OS

Hi Agme
The issue you are having with 3/4 display is that the starting point is not at the left hand side of the display
Have you got a line in your code that looks something like this?
U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); which is used to initialise the display.
To select the right statement for your display, go into the U8glib folder, select the .scr file and open with Notepad++ which is downloadable from https://notepad.software/download
Find the right statement for your display and then copy and paste into your code. Just be aware that there are hundreds of line entries in the .scr file so this might take a bit of time

[Agme]

Actually, thinking about it some more, the audio won't be affected on the ANPI because it's controlled by the analog circuitry, unlike Voodoo.

I attempted to make the display work with the onboard nano. It worked but it was not behaving normal there was jitter in the pulses. And i think some of the analog readings where dropping out. I think i will see if i can use a Attiny chip or something that requires less power to read and display the readings from the board.

I was unable to get the U8x8lib to work with my display. It would only show a 3/4 of the screen.
I found a very small code that might work, but i did not try on the onboard nano yet.

http://www.technoblogy.com/show?23OS

[Qiaozhi]

the top is yellow... Its a happy accident that it kinda works out for this.

I hadn't noticed that. The OLED that I was using is monochrome.

[Qiaozhi]

Thanks for the input. I will try the U8x8lib and see if it will work faster. It would be nice to be able to put it on the Nano that is onboard that way you can add the additional info (batt, threshold, delay) that you added for the voodoo.

Actually, thinking about it some more, the audio won't be affected on the ANPI because it's controlled by the analog circuitry, unlike Voodoo.

[Agme]

Looks really good. Are you using a display with a yellow portion at the top or are using a RGB display?

the top is yellow... Its a happy accident that it kinda works out for this.

[Agme]

Nice.

I downloaded the code and compiled it. It takes 47% of the program space, so would probably fit on an Arduino Nano with the PI code. However, the overhead of the display might affect the audio response of the detector as you suspected. In this case, having a separate display driver is a good solution.

You might also want to look at the Arduino Voodoo code where I used a very similar OLED (an SH1106 as opposed to an SSD1306). In that example I used the U8x8lib instead of the Adafruit_SSD1306 library. -> https://www.geotech1.com/forums/show...883#post287883

Thanks for the input. I will try the U8x8lib and see if it will work faster. It would be nice to be able to put it on the Nano that is onboard that way you can add the additional info (batt, threshold, delay) that you added for the voodoo.

[MartinB]

While looking at the scope I realized that TP10 (after the integrator) was pretty stable indication correlating to the audio signal. I first connected this to an extra Nano (A0) and used the Arduino IDE serial plotter and realized that it could be possible to make an indicator. I had this little OLED screen so I connected it and made a rolling graph. I originally thought it might be possible to connect it to the Nano on the ANPI, but I did not try it. I was worried about how to keep it from messing with the timing and I am a novice programmer. The extra Nano and display add roughly .027 amps to the system. My crappy code is attached if anyone wanted to explore further.

https://imgur.com/HBfN8jf

[ATTACH]55841[/ATTACH]

Edit: I forgot to add reference to where I got the starting code for the rolling graph in the code. I found it here and modified it. https://youtu.be/6-SRpThOZ5I

Looks really good. Are you using a display with a yellow portion at the top or are using a RGB display?

[Qiaozhi]

While looking at the scope I realized that TP10 (after the integrator) was pretty stable indication correlating to the audio signal. I first connected this to an extra Nano (A0) and used the Arduino IDE serial plotter and realized that it could be possible to make an indicator. I had this little OLED screen so I connected it and made a rolling graph. I originally thought it might be possible to connect it to the Nano on the ANPI, but I did not try it. I was worried about how to keep it from messing with the timing and I am a novice programmer. The extra Nano and display add roughly .027 amps to the system. My crappy code is attached if anyone wanted to explore further.

https://imgur.com/HBfN8jf

[ATTACH]55841[/ATTACH]

Edit: I forgot to add reference to where I got the starting code for the rolling graph in the code. I found it here and modified it. https://youtu.be/6-SRpThOZ5I

Nice.

I downloaded the code and compiled it. It takes 47% of the program space, so would probably fit on an Arduino Nano with the PI code. However, the overhead of the display might affect the audio response of the detector as you suspected. In this case, having a separate display driver is a good solution.

You might also want to look at the Arduino Voodoo code where I used a very similar OLED (an SH1106 as opposed to an SSD1306). In that example I used the U8x8lib instead of the Adafruit_SSD1306 library. -> https://www.geotech1.com/forums/show...883#post287883

[Agme]

Itsy Bitsy display for ANPI

While looking at the scope I realized that TP10 (after the integrator) was pretty stable indication correlating to the audio signal. I first connected this to an extra Nano (A0) and used the Arduino IDE serial plotter and realized that it could be possible to make an indicator. I had this little OLED screen so I connected it and made a rolling graph. I originally thought it might be possible to connect it to the Nano on the ANPI, but I did not try it. I was worried about how to keep it from messing with the timing and I am a novice programmer. The extra Nano and display add roughly .027 amps to the system. My crappy code is attached if anyone wanted to explore further.

https://imgur.com/HBfN8jf

md_Display_Test_20.zip

Edit: I forgot to add reference to where I got the starting code for the rolling graph in the code. I found it here and modified it. https://youtu.be/6-SRpThOZ5I

[surfdetector]

Advise needed:
1)I would like to make a new coil. I was going to buy some new wire, but I got overwhelmed with all the opinions of the forum. Would yall recommend a wire size and insulation. What I have concluded is that Teflon insulation is a favorite (I think), but actual wire size is all over the place. And 3DSS coils seem to be a favorite over the Fast coil documentation.
2) I would like to build a VLF next, could you recommend a project to try. I saw the IDX pro is available from DIY detector and I not sure I want to attempt making PCBs yet.

Thanks for the help.

Regarding the VLF project, I think that the TGSL is the best documented so you might want to look at that project to start.

[Agme]

Firstly ... well done on a successful build, and thank you for reporting back to the forum on the results.

You don't need to be obsessed with making a fast coil for the ANPI as it's designed for metal detecting on the beach, not for gold nugget detecting. A simple mono coil is more than adequate, and Teflon insulation would be good. You can use the Coil Calculator at the top of the Coils forum to estimate the correct number of turns for a specific wire diameter.
If you do want to reduce the sampling delay then have a look at ->

https://www.geotech1.com/forums/showthread.php?26315-UXO-Target-Detection-and-Discrimination-with-Electromagnetic-Differential-Illumination

The "Investigation of UXO Paper.pdf" includes a modification to the transmitter circuit which turns it from passive to active switch-off. This reduced the sample delay of 24us to 17us (out of saturation at 15us) for the sample test coil.
I have made good coils with 0.56mm, 0.63mm, and 0.71mm copper enameled wire, and also with simple hookup wire, so it's not really that critical.
Make sure that you adjust the damping resistor accurately to provide critical damping.

Regarding a VLF detector project ... TGSL or IDX Pro are probably your best options.

Thank you for the suggestions. Thank you for the books and support here.

[Agme]

Thanks,
I have a spare opamp I will see if there is any difference.

Dampening resistor - I just followed the instructions and adjusted the resistance while monitoring the scope. I also looked at surfdetector's video.

[Vadim18]

Agme - 45uS for delay is quite large number. U know, probably you need to check or replace frontend opamp first.
And 360 Ohm dumping resistor is a bit low, try 390, 470.

[Qiaozhi]

Hi, I have successfully built arduino nano pulse.
if possible I wanted some advice, the damping resistance better directed in the coil or better on the circuit, on the base?
does the rg58 cable affect a lot in both cases?
sorry english translated Thanks!

As described in Chapter 4, the best position for the damping resistor is on the back of the coil connector. This provides the most flexibility when using different coils.
You could also put the resistor in the coil shell, but this may stop the coil being used on a different detector.
There is a place provided on the PCB, but this is also restrictive as all coils will then need to have identical damping requirements.