Adding smell to a project

Hi all, I'm working on some Arduino-based videogames that have no visual display - just sound, vibration, or other feedback. One of the first experiments can be seen here

I'd like to make a game that uses smell as the output, but am not finding a lot of examples. My thoughts are:

  • Have various scent-generating compounds (probably essential oils) in containers
  • A heater element under each
  • A fan mounted above all of the scents that blows air at the player

Any ideas on how to generate heat quickly and safely? Will this draw a lot of current (and need a separate power supply)? I've looked at the heated build plate from a RepRap/MakerBot (Heated Bed - RepRap) as a starting point, but this draws 6A! Other smell-related ideas?

The project would ideally be very compact, but that's definitely not a requirement - it could be the size of a table if that's what's required for safety and/or simplicity.

Heat = Power.

Power is voltage times current.

Heat is going to require current.

Glow plugs for model aircraft engines will get white hot in matter of seconds and will cool down very quickly as well as. They are tiny and designed to operate from a battery.

@James: of course - I think I realized that but not in such clear terms!

@Shpaget: great suggestion, I'll look into that. Do you have a brand to suggest? Any worry about sparks or fire?

This is a pretty tricky and risky requirement. To vaporize oils to develop smells will most likely require an immersion type heating element of some kind and what you could be doing is effectively (on purpose or not) boiling the oil and as such the liquid oil level will drop as it is vaporized. Oil vapors plus a heat source plus oxygen in the air makes up all three parts of the magic fire triangle. You should have adequate safety defaults designed into the project.


Sparkfun has these 5v heating pads:

They may get warm enough to trigger some scented oils.

No, I don't have any brand suggestions. It's been quite some time since I flew planes.
However, Lefty has a point. They could ignite the oils, perhaps you should conduct experiments to see how hard you need to drive them to avoid ignition. It might be wise to avoid it from functional point as well. Burning oils probably doesn't smell as good as when it is evaporating.
You could also try both separate the oil from the heating coil and immersing the coil in oil to see which method provides better results.

Sparkfun has these 5v heating pads: Heating Pad - 5x15cm - COM-11289 - SparkFun Electronics

They may get warm enough to trigger some scented oils.

I would be somewhat pessimistic that would be useful. Pretty slow to heat up and reaching only 145F after 2 mins or so, it would have to be used with oils with pretty low vapors-pressure values.


Some time ago in a Make Magazine there was a project about how someone took one of those air freshener spray things the sort that you plug in the power socket and hacked it so it was arduino controlled. I seem to remember they filled it with alternate smells.
Google the words:-
air freshener hack

A similar approach could be to hack one of those plug-in chemical mosquito repellers

Or have a servo press down on a small scented aerosol spay can or perfume spray bottle?


4D, 5D, 6D, or 7D movies.
how many D's we need?

Arduino based rain, wind, strobe lights, and vibration. vibrate seat or move a few inches during the presentation. chair effects include air jets, water sprays, and leg and back ticklers. Hall effects may include smoke, rain, lightning, air bubbles, and special smells.

I was at London Eye few week ago, fireworks smells from movie is very impressed.

No Reinvent the Wheel

copied it.

I do reinvent the wheel from time to time, specially when I enjoy the processing more than the result.

BTW I do reinvent the wheel from time to time, specially when I enjoy the processing more than the result.

Like John Water's film Polyester featuring Odorama:

Odorama, a "scratch-and-sniff" gimmick inspired by the work of William Castle and the 1960 film Scent of Mystery, which featured a device called Smell-O-Vision.

You probably could make small vaporizing heater elements out of the thin nicrome wire like below.

Thanks everyone, good suggestions. Grumpy_Mike's suggestion seems the best (read: safest) bet. I found this which looks like a good starting point:

Well a 7805 running off 12V gives off more power as heat than it supplies as electricity.... I measured the temp of one a while back and it got to 110C in no time flat. :roll_eyes: