Arduino Nano PI Main Discussion

[green]

Just guessing. I would think that you have something in your lab that creates a strong magnetic field.
Inside the house it is common to have all sorts of localized magnetic fields. One usually looks for the place or position in the lab, where the least influences are felt for the coil. If this is not possible, the next best is to use always the same place and position.
Any real tests need to be done outside in a magnetically quite place.

Are you suggesting I will see something different if the tests were done outside? I'm thinking my tests confirm the coil has to rotate thru the magnetic field to to generate a voltage. I would be interested if some would lay their detector on a board with the coil flat and rock the board NS and EW to see if EFE is effected compared to waving the coil side to side. And does waving the coil NS compared to EW make a difference.

[Tinkerer]

Test was done with Rx coil only(200mm mono coil). Did some more testing, earth field sample connected to common(no earth field correction). Coil was positioned on a board about 2 feet long. Sliding the coil on the board back and forth didn't cause a signal. Positioning the board NS, South end stationary while moving the North end up and down caused a near +-full scale signal. Positioning the board EW, East end stationary while moving the West end up and down had a small signal. Was able to get minimum signal with a small change in EW direction.

Just guessing. I would think that you have something in your lab that creates a strong magnetic field.
Inside the house it is common to have all sorts of localized magnetic fields. One usually looks for the place or position in the lab, where the least influences are felt for the coil. If this is not possible, the next best is to use always the same place and position.
Any real tests need to be done outside in a magnetically quite place.

[green]

I forgot to ask if the TC is on. Moving the coil in the earth field without the TX on, only the RX, will show the earth magnetic field if it is not compensated by the circuit. If the TX is on, the coil field will induce eddy currents in all conductors for a large distance. The human body is conductive.
We know very little how the eddy currents behave in the human body. Do the eddy currents just circulate in stationary eddies? Or do they discharge to ground? There is so much we don't know.

Test was done with Rx coil only(200mm mono coil). Did some more testing, earth field sample connected to common(no earth field correction). Coil was positioned on a board about 2 feet long. Sliding the coil on the board back and forth didn't cause a signal. Positioning the board NS, South end stationary while moving the North end up and down caused a near +-full scale signal. Positioning the board EW, East end stationary while moving the West end up and down had a small signal. Was able to get minimum signal with a small change in EW direction.

[Agme]

Itsy Bitsy display for ANPI

I think I'm about done with this little OLED Display. I Just need to put it on at perf board and print the case.

https://imgur.com/a/aHuq4LO

I decided to give up on trying to make it small enough to go on the ANPI and just used a spare nano to run it. I set up the on board Nano to transmit the delay status and boost status over I2C when requested. Technically you could change the ANPI values through the display, but the knobs are already there.. Maybe next time.

Connections:
ANPI (A5) - Display Nano (A5) - OLED (SCL)
ANPI (A4) - Display Nano (A4) - OLED (SDA)
ANPI (VIN) - Display Nano (VIN) Thru Display power Switch - Voltage Divider
ANPI (GND) - Display Nano (GND) - Voltage Divider - OLED (GND)
ANPI (TP10) - Display Nano (A0)

Voltage Divider (220K/100K) - Display Nano (A1) 5V=16V

Display Switch (1) - Display Nano (D3)
Display Switch (2) - GND

OLED (VCC) - Display Nano (5V)

I am not certain if I need pull-up resistors on the SCL/SDA lines. I think the display already has them so I didn't add them.

Sorry I an lazy and don't want to draw a schematic. I can if someone really wants me too.

I dont really like the case drew.. I will provide models when I'm done with it.
Also I'm not sure how it will work in real world test... I will let you know when I get it mobile.




Revised Code for ANPI and Display Nano attached. I just used the Adafruit OLED Library.. it works for me and I was tired of trying to make the other libraries work on the display that I have.

OLED Test.zip

[lamoiz]

otherwise, the nano with the 32 coil works really well; the guys who are with me at the beach all have ctx3030 eq800 and sovereing minelabs. we did the depth test with the sovereing elite, and the nano. the result is very very close if the nano uses the boost.

[Tinkerer]

I've been thinking a coil has to rotate in a magnetic to develop a voltage. Moving a coil in the Earth field with no NS rotation shouldn't cause a voltage. Maybe I've been thinking wrong?

I forgot to ask if the TC is on. Moving the coil in the earth field without the TX on, only the RX, will show the earth magnetic field if it is not compensated by the circuit. If the TX is on, the coil field will induce eddy currents in all conductors for a large distance. The human body is conductive.
We know very little how the eddy currents behave in the human body. Do the eddy currents just circulate in stationary eddies? Or do they discharge to ground? There is so much we don't know.

[green]

I would say, that what you see, is your body field, not the earth field.

I've been thinking a coil has to rotate in a magnetic to develop a voltage. Moving a coil in the Earth field with no NS rotation shouldn't cause a voltage. Maybe I've been thinking wrong?

[lamoiz]

last night, I detected 3 hours non-stop with nano. I confirm that I hear the salt in the wet sand .. yet great care has been taken to shield this one ..

[Tinkerer]

If it sounds like an Earth field problem, you can prove / disprove that by waving the coil in the air from side to side away from the ground.
I'm wondering if there is an Earth field signal if the coil is waved side to side away from ground. Holding a coil on the East and West edges while rocking the coil so the North and South edges go up and down causes a Earth field signal for me. I'm not seeing one when I wave the coil side to side or rock the coil with the East West sides going up and down.

I would say, that what you see, is your body field, not the earth field.

[green]

All the timing is done by the Arduino Nano, so it's not really possible for the timing to drift due to temperature. I would suspect that it's something to do with the coil.
If it sounds like an Earth field problem, you can prove / disprove that by waving the coil in the air from side to side away from the ground.
What happens if you turn off the detector for a few minutes and then turn it back on? Does the problem go away?

If it sounds like an Earth field problem, you can prove / disprove that by waving the coil in the air from side to side away from the ground.
I'm wondering if there is an Earth field signal if the coil is waved side to side away from ground. Holding a coil on the East and West edges while rocking the coil so the North and South edges go up and down causes a Earth field signal for me. I'm not seeing one when I wave the coil side to side or rock the coil with the East West sides going up and down.

[lamoiz]

All the timing is done by the Arduino Nano, so it's not really possible for the timing to drift due to temperature. I would suspect that it's something to do with the coil.
If it sounds like an Earth field problem, you can prove / disprove that by waving the coil in the air from side to side away from the ground.
What happens if you turn off the detector for a few minutes and then turn it back on? Does the problem go away?

the problem appears after a certain time of detection. 1h30 or 2 hr the problem occurs. If I switch off and turn on the detector, the problem remains the same.
for the voltage regulation of the power supply module, I use 2x 18650 li ion and an xl6009 module to maintain a permanent 12v
tomorrow I will test the coil on an analog surfPI to see the problem comes from it or not.

[Qiaozhi]

Hi all.
I'm at the beach, and every night I'm with the nano. I notice a phenomenon: at the start of detection, there are very few false signals, then after 2 hours of use, false signals appear(earth fields) . the battery voltage is always at 12v, from start to finish. I specify that I am on the wet sand of course. the phenomenon is attenuated if I switch to boost mode. George, do you have an explanation?
thermal drift of a component? or maybe just sand stuck under the coil ..? to validate the stuck sand, this evening I will pass the coil in sea water as soon as the phenomenon appears.

All the timing is done by the Arduino Nano, so it's not really possible for the timing to drift due to temperature. I would suspect that it's something to do with the coil.
If it sounds like an Earth field problem, you can prove / disprove that by waving the coil in the air from side to side away from the ground.
What happens if you turn off the detector for a few minutes and then turn it back on? Does the problem go away?

[lamoiz]

Hi all.
I'm at the beach, and every night I'm with the nano. I notice a phenomenon: at the start of detection, there are very few false signals, then after 2 hours of use, false signals appear(earth fields) . the battery voltage is always at 12v, from start to finish. I specify that I am on the wet sand of course. the phenomenon is attenuated if I switch to boost mode. George, do you have an explanation?
thermal drift of a component? or maybe just sand stuck under the coil ..? to validate the stuck sand, this evening I will pass the coil in sea water as soon as the phenomenon appears.

[Carl-NC]

I have moved this thread to a dedicated Arduino Nano forum. I encourage people to open new threads for particular discussions so it becomes easier for others to find relevant information. If you have posts in this thread you would like extracted to a separate thread let me know.

[MartinB]

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.

U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); works very well with my yellow and blue OLED which is in another project.

Try the following;


#include <U8g2lib.h>
#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>

U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);

void setup() {

u8g2.begin();