How does an Alcohol Detector work?
Hey gadgeteers, Happy Wednesday!
Let’s look at how Breathalyzer (Alcohol detector) works this week. I aim to write my newsletter issues in a way one can follow them while traveling on a bus, having a coffee, waiting for food, etc. Let's jump in!
How it works: 15-second answer
Breathalyzer technology measures blood alcohol concentration (BAC) by analyzing exhaled air. After drinking, alcohol is absorbed into the blood and eventually evaporates into the lungs, and finally, it's exhaled as vapor. Fuel-cell sensors with platinum electrodes react with ethanol in exhaled breath, producing electrons proportional to alcohol concentration. This current is converted to a BAC reading displayed digitally.
Answer to the question I posed last week
Last week, I asked what different types of life vests you have come across or know about. These are automatic inflation jackets that use water pressure to detect, manual inflation jackets with a pull cord that releases gas, and hybrid jackets that use a combination of two.
Recommend a gadget for me to write about?
Some of the popular newsletters in the past have been gadget recommendations from the awesome readers I have, you all! So if you have any gadgets that you'd like to learn about, please take a few seconds of your time to fill out this form below, thank you.
How does a Breathalyzer work?
What is a Breathalyzer?
It is a device where you blow air through a straw-like mouthpiece and a sensor processes it chemically to tell how drunk you are by showing the percentage of alcohol in your blood on a digital display.
Figure 1: Breathalyzer device
Why do we use the exhaled air to tell if a person is drunk?
Here is what happens when you drink.
The blood absorbs alcohol through the stomach (20%) and small intestine (80%).
As the blood circulates through the body, a small amount of the alcohol evaporates and enters the lungs during the respiration process.
This alcohol vapor in the lungs is then exhaled when we breathe out. The more alcohol you consume, the higher the concentration of it in your breath.
Thus, we can tell how drunk a person is by analyzing the breath.
How does a Breathalyzer work?
The most accurate sensors in the market used by cops and others, in general, today use a simple technology called fuel-cell sensors. Fuel cell sensors used in Breathalyzers have platinum electrodes placed in them.
A keyword definition before we proceed.
Electrode: An electrical conductor used to make contact with a nonmetallic part of a circuit like exhaled air in our example.
As exhaled air passes through the mouthpiece and comes in contact with these platinum electrodes placed inside, a chemical reaction happens with the ethanol in our breath as follows. I have simplified this process for a better understanding.
Figure 2: Ethanol vapor in our breath reacts with platinum electrodes in the device to produce electrons. The more electrons, the higher the concentration of alcohol
The higher the alcohol concentration, the more electrons produced from this reaction. Through basic physics, we know that current is the flow of electrons. So the more electrons, the higher the current in the circuit detected.
This current is then mapped to a concentration of blood in our alcohol that is already pre-calibrated, finally displaying the concentration as a number on the display. This is how a Breathalyzer works! The legal limit for driving in the US is 0.08% alcohol in the bloodstream.
Thus, the cops can catch us and put us in jail. Just kidding, it depends on how drunk we are.
Question of the week
What are some ways by which you can cheat the Breathalyzer? Reply to this email with your thoughts, and we’ll discuss.
Note: By no means am I promoting this, and the discussion is only for elevating our appreciation for the wonders of technology :)
Gadget of the week
Baby Monitor: Maxi-Cosi developed a baby monitor to stay connected to your child even when you’re apart using a live streaming monitor with night vision and two-way talking capabilities. It has an AI feature called CryAssist that detects a child’s cries and translates them to understand if the baby is sleepy, fussy, gassy, or hungry. This feature sounds really cool, from a technical standpoint.
That’s all folks. Thank you for reading!
Have an amazing rest of the week, and take care!
Until next to next Wednesday,
Chendur
