text: Flame-igniter(top)-and-flame-sensor in arduino - Project Guidance - Arduino Forum
  Flame-igniter(top)-and-flame-sensor in arduino
  solimaniashkan June 23, 2020, 8:36am #1
  Hi, my friends, I want to use the Flame-igniter(top)-and-flame-sensor, which is used in boiler heater water packages, and its job is to detect the flame. I will design a circuit with Arduino and this read that will detect the flame for me and start the relay and so on. When a flame hits the ion bar, a microampere current is generated. How can this microampere current be detected and detected by Arduino? Thank you for your suggestion.
  6v6gt June 23, 2020, 12:13pm #2
  Can you link to a product page or data sheet describing this device.
  Very small currents can, with an appropriate op amp circuit, be turned into measurable voltages, say in the range 0 to 5 volts, which you can read with an analog pin.
  See, for example an outline circuit, Circuit 9 here: https://www.arrow.com/en/research-and-events/articles/fundamentals-of-op-amp-circuits
  AVR arduinos also have an on board comparator which could also be used, but probably not directly in this case.
  Also, this may be relevant: Pilot Light Flame Sensor for Burning Man Art
  solimaniashkan June 25, 2020, 5:53am #3
  Hi my friend, I'm a little confused and haven't worked with op amps yet. I have seen the circuits of wall-mounted radiator packages, the ion rod is connected to the mega ohm resistor, and the sites are said to generate a current of 50 to 100 microamperes. Is there another way to detect a flame?
  6v6gt June 25, 2020, 9:14am #4
  These flame detectors work on different principles
  A thermocouple. For this you need a matching amplifier. This is an example. Thermocouple Amplifier MAX31855 breakout board (MAX6675 upgrade) : ID 269 : $14.95 : Adafruit Industries, Unique & fun DIY electronics and kits
  Flame rectification. Read this: Pilot Light Flame Sensor for Burning Man Art which includes a description and circuit.