Connect a sensor to Arduino without knowing much info about the sensor I am planning to buy a formaldehyde sensor and I would like to connect it to an Arduino Uno board (and later to a Raspberry). As far as I know, the sensor comes in a small box/bag without any other external components (e.g. amplifiers etc.). So I will end up having in my hand a sensor with two copper terminals for connection (see image below):



Is it possible to connect this to an Arduino board without having a connection scheme? If yes, where do I connect the two terminals of this sensor to the 5V, GND and the A## ports? Also, how to translate the voltage coming from the sensor to ppm (parts per million) only by having general specifications from the manufacturer and not some kind of table of conversion? Also, would I need an external component for this? If yes, which component?

I know that this question sounds very stupid, but so far I've used sensors that come with a code on Seeed Grove with a clear description and I assumed that the code is there because there is a link between the producer of a certain sensor and Groove. Thank you!

FYI: The producer writes some things about the sensor but that doesn't help me a lot:


  This sensor is of the two-electrode electrochemical type, operating by the
  diffusion principle and as such requires no external sampling hardware. In
  the presence of formaldehyde gas a small direct current is produced; the
  sensor requires no power supply of its own but this current requires
  amplification to make it readable using external data collection
  equipment.
You have linked to the datasheet of the sensor.

In the datasheet, look at the "Application Circuit" section. You must build this circuit. The sensor produces a very small electric current, and the application circuit is high-gain amplifier to translate that very small electric current to a varying voltage you can sample with the Arduino ADC.

Note on the circuit, the wire labled "To ADC" -- that is the part which you connect to your arduino.

As for calibration, the datasheet itself notes that the process is non-trivial, or that they can perform a calibration, for an additional fee, at the time you order a batch of sensors. Presumably their calibration will include the precise resistor values used to set the gain of the amplifier, and also an equation to associate PPM values to the analog voltage provided at the "To ADC" wire.

As for reading the circuit diagram (schematic), you may already know resistors and capacitors. For the other items, search online for the part numbers given, to find out what they are.

The datasheet also notes that the application circuit is available pre-built from the sensor manufacturer. You may want to contact them to determine how to purchase one for yourself.

Most electronics products have a datasheet that explains all you typically need to know about the device, such as it's operating parameter minima and maxima, typical values, typical outputs, etc. This sensor is no different, except that the calibration procedure is not described in great detail due to the complexity.