The Ignition Interlock Device:
What if machines performed a test for impairedness instead of a police officer? The ignition interlock device is an in-car alcohol breathalyzer. When the driver first turns on the car, he/she is required to blow into the device. If the device finds the driver’s BAC above the legal limit, the car will be prevented from starting. Once the vehicle has started, the driver is asked to provide breath samples randomly. If the samples are found to have a BAC higher than the legal limit, the vehicle sounds the horns, turns on the lights, and uses other indicators. The event is also recorded onto the ignition interlock device.
Problems with the Ignition Interlock Device:
- A passenger or another item (fan) could provide the sample
- Very expensive for the driver ($150 installation, $50 removal, $105/month monitoring fee)
- Maintenance checks are tedious and frequent
- Random checks could be hazardous to the drivers as their concentration could be broken. This could potentially cause accidents
- Long waits for the data to initialize and record
- Car doesn’t stop when alcohol is detected; damage could still be done
The purpose of this project was to create a device that is an improvement from the ignition interlock device. Like the ignition interlock device, if the driver’s BAC was above the legal limit, it would signal the car’s computer. However, the device created would slow down the car and turn on indicator lights. The car would eventually come to a stop.
In order to gain accurate readings of the driver’s BAC, alcohol sensors would be placed around the driver. Those places would be the driver’s seatbelt, the dashboard, on the driver seat, and other strategic places. The airflow in a car goes from the front to the back which means passengers seated in the back wouldn’t be sensed accidentally. The sensor on the back of the seat would be able to use that air to check for the driver’s BAC. The dashboard and steering wheel are good choices because when a driver breathes out, his/her breath would move to the steering wheel and dashboard. Slowing down the car to a stop would let the car behind have enough time to slow down or move around the car. Also the intoxicated driver wouldn’t be able to cause damage to themselves and/or others in a stopped car.
We tested our alcohol sensor using different sources of alcohol. We used beer (5%) because it is one of the most common types of alcohol in modern society. Wine (13%) was also used to check if the sensor was working. Isopropyl alcohol (rubbing alcohol), hand sanitizer, perfume, and mouthwash were used to check if common alcohol-containing products could set off the alarm.
When we were coding our alcohol sensor, we found that calibrating the sensor to sense actual blood alcohol levels was difficult. In order to do that, we would need a pre-programmed breathalyzer so that we could expose our sensor to an exact amount of alcohol. Using a better alcohol sensor would make the breathalyzer more accurate. The breathalyzer we built is very much still a prototype.
But there are several pros to our breathalyzer as well. Our breathalyzer was very cheap and the materials were easy to find. The breathalyzer requires 5V to operate, making it very efficient. The sensor works as wanted to; testing for alcohol consistently and preventing the motor from turning on if a certain amount of alcohol is detected. It would be fairly easy to install and would be discreet, so it would not be embarrassing.
The breathalyzer we made was an improvement from the ignition interlock device in some areas but needs some further refining in others.
To improve the breathalyzer, we would need to use a sensor that is even more sensitive to alcohol. Also the sensor must be calibrated to check BAC instead of the percent of alcohol. To improve this project, we could also put different types of alcohol sensors in the car to make results even more accurate. There are transdermal...Read more »