Feasibility of ACS712 in testing electrical conductivity of Fire

[workinprogress]

I'm planning on replicating this circuit described below (see attachment).

In my set-up, I'm using a 30V step-down transformer as the AC power supply. One end of the wire attached to the transformer to a metal barrel as ground, and the other end of the wire about two inches where I expect a flame to be. I've created a the fire by running a plastic tube attached to a butane can through the metal barrel.

Like the results in the journal, I found that there was a DC voltage running through a 1watt resistor. I measured this with a multimeter. I found that arduino has a current sensor that could measure DC (and seems to be ok with AC current running through it too). I have a 20A model right now.

So my question is, Can you replace the resistor-and-multimeter with an ACS712 current sensor?.

thompson2014.pdf (1.17 MB)

[Paul_B]

workinprogress:
Can you replace the resistor-and-multimeter with an ACS712 current sensor?.

Totally useless. I won't even explain why!

OTOH, just ground your metal barrel to the Arduino ground, connect the nichrome wire to an analog input and also a 10 M resistor to 5 V and see if you get a reading. If not, exchange the barrel and wire connections.

[JohnLincoln]

The article in the attachment suggests that the current is of the order of 0.4µA.

You aren't going to be able to measure a current less than one millionth of an Amp using a 20A rated sensor.

[TomGeorge]

Hi,
Ops pic.

Tom..

[DrDiettrich]

workinprogress:
I've created a the fire by running a plastic tube attached to a butane can through the metal barrel.

Then you miss any electric connection between the barrel and the flame.

It's hard to understand where electricity can go because it is invisible. For better results hold two wires into the flame and measure the resistance of the plasma in between them.

[workinprogress]

JohnLincoln:
The article in the attachment suggests that the current is of the order of 0.4µA.

Ahhh... I should've added to the original post that I measured 1V DC with my setup. I guess it's because I used a lower rated resistor and passed through 30V AC instead of 20V that the journal used.

DrDiettrich:
Then you miss any electric connection between the barrel and the flame.

It's hard to understand where electricity can go because it is invisible. For better results hold two wires into the flame and measure the resistance of the plasma in between them.

I did the holding two wires as an initial test.
I'm sorry. I think my explanation was unclear and misleading. I attached the end of the plastic tube to the metal barrel (with duct tape).

[workinprogress]

Paul__B:
OTOH, just ground your metal barrel to the Arduino ground, connect the nichrome wire to an analog input and also a 10 M resistor to 5 V and see if you get a reading. If not, exchange the barrel and wire connections.

( I think I'm just scared of frying my arduino but) Can Arduino really withstand 30V AC?

[GoForSmoke]

DrDiettrich:
It's hard to understand where electricity can go because it is invisible. For better results hold two wires into the flame and measure the resistance of the plasma in between them.

Butane flame is not plasma. It is butane combusting into ionic molecular end-products.

There is a Veritassium video on Youtube showing experiments with high voltage static plates and flames. When + and - are held on opposite sides of the flame, the flame SPLITS with + ions going one way and - ions going the other.

Conductivity of flame? Stick 2 wires in the flame and check continuity on a meter first. Make sure it works both ways (probably will but flame as diode would be neat) and then see if it can be used in a voltage divider, or that's what I'd try.

Electrical pressure in a wire rises with temperature of the wire (Fermi level) so it's not going to be easy to interpret the results accurately.

[DrDiettrich]

Conductivity in a flame can not only be caused by free electrons but also by free ions, which result from the burning process. A hot wire by itself emits almost only electrons, this flow can be measured between a hot (cathode) and a cold (anode) electrode. Every current above that value must be caused by ion migration inside the flame.

[6v6gt]

You might also find something of interest here: Pilot Light Flame Sensor for Burning Man Art

[Paul_B]

Which points out a few things in my previous suggestion.

• AC is unnecessary and inappropriate.
• 30 V is unnecessary. The Arduino 5 V should be plenty.
• I don't think an amplifier is in any way necessary. The Arduino has a high-impedance input already.

[workinprogress]

Hello!

Paul__B:
OTOH, just ground your metal barrel to the Arduino ground, connect the nichrome wire to an analog input and also a 10 M resistor to 5 V and see if you get a reading. If not, exchange the barrel and wire connections.

I did this, and it gave me something! Thanks! I realized that I was complicating things.

I've attached a screenshot of the results I got with the serial plotter. It seems like voltage always decreases (even after trying to exchange the barrel and wire connections). Results always 'stabilized' between 100-200 (y axis units) range.

(For future references) Here's my very simple code:

void setup() {
  Serial.begin(9600);
}
 
void loop() {
  int val=0;
  val= (analogRead(A0));
  Serial.println(val);  
  delay(500); 
}

I'm not sure how to interpret the data, but it seems like the fire is recorded in the plotter as a form of resistance, in contrast to what my original journal reported. So I guess, if I introduce a bit of some other organic substance midway while supplying butane, I should get a negative spike in voltage reading.

[TomGeorge]

Hi,
Ops screenshots.
Serial Plotter

Setup;

Tom...