I recently found a 2 Pin flame sensor. It looks just like an LED except it's black. It is not a module and I couldn't find any wiring tutorials for these, just for modules. Does anyone know how to wire this? Also, why would it be wired so? Thank you
Here is how it works. The photo-transistor starts conducting when it gets IR light from a flame or any source strong enough. A comparator can be used to convert it to a digital output. The second link above has a schematic that the Arduino modules use.
That being said, this could also be a photo diode since I couldn't find any official specification on this component. The working principle would be similar but the wiring would be different. Basically you could wire this like any other photo diode or transistor. I would wire it in different ways and measure the changes in current/voltage when pointing to a flame. You could start with the schematic below and use a multi-meter to measure the output voltage.
This is probably a YG1006 flame sensor.
I found this in another kit's description: "The Flame sensor is a high-speed and highly sensitive NPN silicon photo transistor based on the YG1006. It can be used to detect fire or other wavelength at 760nm ~ 1100nm light. Response time is 15us, supply voltage is 3.3-5V; output is analog."