Arduino metal detector?

[6666]

PULSE RATE - pulse repetition rate (10/20/30/40 pps)

Foxylab I am curious for your reason why you choose a very low pulse rate ?

[6666]

Hi Foxylab thanks for the updates

[FoxyLab]

FoxyPI v3

The third version of pulse metaldetector on Arduino Nano (FoxyPI v3) (transition to the use of the Arduino ADC and dynamic mode) is ready.
Firmware (hex-file) and description (on russian, edited under the third version) - https://acdc.foxylab.com/node/47
Test video -

[ivconic]

> I want to make VLF MD with Arduino Atmega328, what is the scheme of the front (Coil and Buffer) so that it can be connected to the Atmega analog pin?

https://github.com/dc42/arduino/tree/master/MetalDetector

[Joo]

> I want to make VLF MD with Arduino Atmega328, what is the scheme of the front (Coil and Buffer) so that it can be connected to the Atmega analog pin?

[FoxyLab]

Hex-file FoxyPi (version 2.11) for Arduino Nano 3.0 - https://acdc.foxylab.com/sites/defau...aloginputs.hex
How to flash (in russian) - https://acdc.foxylab.com/avrdude

[jlsilicon]

ok, thanks !

[Altra]

Look here

http://www.ti.com/lit/ds/symlink/lm385-1.2-n.pdf

[jlsilicon]

What is the VD3 in the Schematic ?
- The spec calls it a 3pin VRef .
- But the schematic shows its config as a Diode.

How do I connect this ?

[bernte_one]

some News on this Project?

[homefire]

Ok, See if the Cap stretches that out.

[kosacid]

lol it go`s to sign wave when metal is near the coil im using a lm358 opamp

[homefire]

In your screen shot it goes from some what square wave to sign. What's that about ? Try adding the Cap. See what it does.

[kosacid]

i replaced R8 with a trimmer to fine tune the gain i dont see no ringing it only changes when it detects metal ? the cap works to i used a 101 cap

[homefire]

Added Trim. Series? Parallel ? Or Replaced R8 ?

Looks like the output of Op Amp is ringing. That's why the Erratic indications I bet. I don't know what the Hysteresis or trigger level is on the Arduino.

I assume this is BreadBoard work ? Add a Integrator section with off set adjustments and I bet this thing will work quite well taming down the ring and getting the Arduino input stable.


Just Thinking here. Try adding like a 50pF in parallel with R8 to Integrate the signal into the Arduino. See if things tame down some.