A very curious device that I found in every apartment when I originally moved to Brooklyn, was this white circle shaped plastic protuberance hanging from the ceiling in almost every room. I must mention that back then, I also moved in with my own black circle shaped metal device also known as a “comal”. A comal is a cast iron flat plate to cook everything from tomatillos, cecina to tortillas and everything in between. It was not long until I discovered that both of them didn’t like each other. Every time I turned the comal on to prepare a midnight quesadilla, the white protuberance on the ceiling started howling as if I was a thief. What was so important to guard that couldn’t wait for my midnight snack to be ready? Now I know, it was my own life.

I was about 8 years old on a christmas family reunion when I discovered the smell of kitchen gas (I figured later, that smell was added on purpose). I remember standing there in the kitchen inhaling what I assumed was a delicious toast bread smell. My aunts rushed in and made a big deal because gas was leaking, opened the windows etc. Additionally they decided, that it was a good moment to give little R a good life lesson and proceeded to give me a bunch of facts on how dangerous gas was, how many people die every year from poisoning, etc. From that moment on, I became obsessive about it, always (literally every day) checking whether the stove was not on before going to bed or when coming home. The irony is that all this time I’ve missed the main cause of death for this kind of accidents: Carbon Monoxide. Assuming no explosion, Natural gas kills you the same reason water kills you when you drown: Lack of Oxigen to breath. You’ll get drowsy before it is lethal. On the other hand, Carbon Monoxide kills you because it attaches to your red blood cells resulting in your body not being able to capture the right amount of oxigen for a prolonged amount of time (1). In the former, the risk stops as soon as you leave the room (on time), the latter: it’s a death sentence if you are not treated fast enough.(3)

If you search for CO sensors on the internet you’ll realize they are extremely affordable. So, if CO is easy/cheap to detect, why are there still horrible accidents happening? 

Burning Natural Gas (properly) does not produce Carbon Monoxide. That means you can cook a soup for 4 hours straight in the middle of the winter with the windows closed at no risk. However, a bad flame (usually other color than blue) or preparing quesadillas in a comal, using an iron cast skillet or a poorly maintained gas water heater indeed produce CO (1).

What to do about this? First of all, get a couple of those white rounded plastic protuberances (CO sensors) and install them in the kitchen and rooms. However, detecting CO is half of the solution. A smart home should be able to do something about it in addition to sounding the alarm. My proposal is to remove the human from the loop. Same as AirBags in a car that just act when there is danger to protect the passenger, something in the kitchen or room should just act upon the threat of excessive Carbon Monoxide. 

Following: a far fetched concept on how to solve this problem, we need to start somewhere right?

Basic Idea

When you’re in a gas station, pay attention to what’s on the ceiling. A massive installation of something that looks like Medusa’s hair, it is a series of hoses pointing to you that will throw fire extinguishing foam to you and your car in case of fire. The point I’m trying to make is that in emergencies, everything is valid: Even soaking your client with foam (sounds like a Punk’d episode). What I’m proposing as a concept is something a little bit radical: To suck all the air in the room instantaneously and expel it out of the kitchen replacing it with fresh air from outside. It doesn’t even matter if outside is 0 Celsius (32F), what matters is that the room got detoxed and you’ll be fine.

Plan of Action

In a nutshell what I’m proposing is to have a return air fan and a set of separate dampers that will open at the dangerous CO levels event to let toxic air out and fresh air in. The fan needs to be big or powerful enough to recycle the room’s air fast enough. A better option is to be a little less radical and have the system detect CO early on and start moving air out before it becomes dangerous. In either case I need to make a hole on the wall or on a window for the air to flow in/out without having to depend on a sack of flesh (the human) to open the windows.

Regarding the actual CO sensors, I’m not a big fan of reinventing the wheel (although that’s what we do in this blog all the time), for that reason, it would be ideal to reuse the already commercially available ones. Maybe we could have a microphone that detects the loud alarm sound, to trigger the air flush sequence. As usual, humans (like me), will press the “silence” button in the alarm and keep preparing the quesadillas however, by then the CO Flusher would have already started the sequence of opening the dampers and start the exhaust fan. That way we get the best of both worlds: The human has been notified, and there is an actual automated action going on to clean the air.

In commercial buildings you have two independent air ducts: One for AIR IN and another one for AIR OUT. Additionally, there are cooling and heating coils in the air return to remove humidity from outside air and to heat/cool the air before it is returned to the room. However in this case, we use the same duct for IN and OUT intermittently to avoid the hassle of installing two ducts.

Design Notes

• The most basic setup consists of a fan microphone and orchestrator, the dampers are optional but needed to keep the room insulated from external weather.
• The internal CO sensor is used as a backup and to validate the alarm.
• The orchestrator is needed to translate the sound into an event that will trigger the servo controller to open/close the dampers and for the drive controller to start the fan. Additionally, it approximates how much air flow has passed through the duct and reverses the motor for it to bring in fresh air.

Further Improvements

+ A set of temperature sensors and cooling and heating coils for incoming air to be at room temperature

+ A set of humidity sensors for outside air to be dehumified

+ A smarter orchestrator that could turn this prototype into a mini HVAC system.

Top of Mind Conclusions

Installing a system like this into an existing house or apartment would be a little bit complicated, however in new constructions it could be part of the default installations making it transparent to the user. This system could also be useful in small houses that require indoor fire burning (stoves, fireplaces, etc) and in any kitchen in the world where quesadillas are prepared…

This idea follows the Zombie Home Manifest

Read More

(1): https://www.mayoclinic.org/diseases-conditions/carbon-monoxide/symptoms-causes/syc-20370642

(2): https://www.healthline.com/health/gas-leak-symptoms

(3): http://ipcblog.org/2009/12/15/know-the-difference-between-carbon-monoxide-and-natural-gas/