Middle school student - Needs a mentor


I would like to build a school project to sense Volatile organic compounds.
I would like to use arduino uno board and a volatile organic gas sensor.
Where and how do I begin?

I have never built anything before. This is my first. I would be much obliged if an experienced guru can be my mentor.

Umm, I would suggest starting with something a lot simpler before you tackle your chemistry problem.

And volatile organic compounds is quite quite a range of things. Please be specific what compounds you need to recognize (i.e. different sensors may be needed for instance).

Given the word 'volatile', I would imagine given you are not an adult, you would need to get the approval of parents (if doing it at home) or your chemistry teacher (if at school) before venturing into this.

The below sensors might be of use, the methane one might be interesting.


Do you have an arduino yet? Which one?
How do you plan to display the results of your input?
Have you downloaded the IDE, and examples? Have you reviewed the examples or actually loaded them to the arduino?
How long do you have to complete this project?
Do you have access to funds to purchase the needed parts?

Where and how do I begin?

I suggest you start by learning about the range of sensors available to sense the things you need to sense, within your budget. Then research the sort of interfaces they provide and see if any of them seem likely to be compatible with an Arduino. If the supplier states they’re compatible, you’re practically home and dry. If not, you’ve got a potentially quite difficult job ahead of you to match the device’s interface requirements up against the Arduino’s capabilities and work out whether and how the Arduino can control that sensor, and then design, code and test the software to do that interfacing. Then you’re in a position to start work on your sketch which uses readings from that sensor to do whatever it is that you want to do.

Thank you for the encouragement.

I read the forum and have seen all past project discussions.

My school science project is to build a setup that measures the relative VOC (volatile organic compound) level of gases at various places in and around my home and school. The gases levels don’t have to be precise in the first experiment. I want to see which place have highest level of gases (like benzene, alcohol or formaldehyde).

Per my research I believe I will need an Arduino Uno R3 board, a bread board and a MQ138 gas sensor besides some jumper cables. But I don’t know if I need anything else. I have some Java and Perl programming knowledge but I don’t know if the sensor calibration or programming would be much more complex.

I have been given only 2 weeks to complete unfortunately.
Thanks for helping a new student.


ps: (In the future project, I hope to build a pesticide level measurement system. But I need to start small. )

These should get you well on the way :slight_smile:


Per my research I believe I will need an Arduino Uno R3 board, a bread board and a MQ138 gas sensor besides some jumper cables. But I don't know if I need anything else.

The data sheet for that sensor (and the others like it) show a need for a resistor or potentiometer to form a voltage divider so you can get a reading from it. Also consider getting more than one sensor so you have a way to debug if it doesn't do anything. Don't forget the burn in period for the sensor - get it started when you receive it.

How are you going to display what the sensor reads? Easiest is probably to carry it around attached to a laptop, but to make it standalone, you're going to need more hardware for power and display.