Drivers who have just received a personal breathalyzer tend to look first at the power button, the mouthpiece, and the numbers on the screen. Especially when heading to work the morning after a company dinner, or when worried about a family member's driving, you want to test quickly and reach a conclusion. But what self-checking needs first is not memorizing a button sequence; it is deciding what to check in the instructions for the device you actually have, and in what order.
A personal breathalyzer is a reference tool that lets drivers reflect on how alcohol may be affecting them. The fact that it shows a number does not automatically decide whether you can drive. When using it for the first time, read in order from confirming the model name through the ready screen, the test procedure, the result units and error indicators, and the decision about how to travel after the test, so that you do not rush to rely on a single number.
Match the device name with the manual cover first
When you open the box, compare the model name on the device with the model name on the cover of the user manual. Even if the brand is the same or the product names are similar, you cannot assume the button layout, screen display, or smartphone connection method are the same. If you apply a video for another model, or the sequence someone else remembers, as is, you may misread what the screen means.
The official product information for the AF-40BT lists the device, a smartphone application, batteries, a mouthpiece, a carrying pouch, and a user manual as components. Rather than treating the manual as a book for learning every feature at once, it is more practical to keep it as the reference for finding the screens and indicators you need before setting off.
| Item to find first | What to read in the manual | What to do after reading |
|---|---|---|
| Applicable model | Whether the model names on the device and the manual match | Do not mix in instructions for other models |
| Test flow | Indicators that distinguish the ready, testing, and complete screens | Use the device in the order the screens change |
| Results and warnings | What the number units and error indicators mean | Read the number together with the status indicator |
| How to get help | Where to inquire when the manual does not resolve the issue | Do not change settings based on guesses |
This order is not a procedure for pressing fewer buttons. It is an order for telling whether the result on the screen is the completion screen of a normal test or just a ready screen or an error indicator.
Read the ready, testing, and complete screens separately
Rather than waiting for a number to appear right after switching on, first check in the manual what indicator shows that the device has finished preparing for a test. The official AF-40BT information gives a warm-up time of within 5 seconds and an analysis time of about 2 seconds with no alcohol and about 6 seconds at 0.050%BAC. This information tells you that screen transitions can take time; it is not a basis for calculating when you can drive.
For preparation conditions, such as waiting before a test or the state of your mouth, the instructions for that model take priority. If the screen is not in the ready state or shows an error, do not interpret the number or indicator shown at that moment as a valid result. It is better to look up the meaning of the error and the next step in the manual, and if that does not resolve it, to use the manufacturer's support channel rather than repeating operations at random.
Read numbers together with their units and status
The AF-40BT can display results in %BAC, ‰, and mg/L. %BAC is a way of expressing blood alcohol concentration (BAC), and ‰ and mg/L are also units for expressing alcohol test results. So do not just remember a number like "0.00" or compare it with someone else's reading; read it as one unit together with the unit shown on the screen.
The display range in the official information is 0.000 to 0.500 %BAC, 0.00 to 5.00 ‰, and 0.00 to 2.50 mg/L. This only describes the range the device can display; it does not mean that any number permits driving. Even when viewing earlier results stored on the same device, you cannot assume that the situation then and your condition now are the same, so do not use past records or the current result as a driving permit.
In a hypothetical pre-commute situation, settle your travel plan too
As a hypothetical example, suppose someone who attended an evening gathering the day before turns on the breathalyzer before commuting the next morning. The first thing to observe is not a single result number, but whether the device went through the ready screen and completed normally, what the unit is, and whether the person is still worried about the effects of alcohol or fatigue. Concluding whether to drive based only on having slept or having tested once is not the role of this device.
If it is hard to be sure what the screen means, or the result seems doubtful and you also feel different from usual, the conservative interpretation is not to decide on driving based on that value. Possible actions include choosing another way to travel, such as public transportation, a designated driver service, or having a passenger drive, and adjusting your schedule. The completion criterion in this situation is not getting the number you want on a retest, but having a travel plan that does not depend on you driving.
The app and storage features do not widen the scope of reference
The AF-40BT supports both standalone use and use linked to a smartphone app, and the official information lists Bluetooth 5.0 LE and storage of up to 10,000 test results. If results remain in the app or on the device, you can use them to look back at the fact that you tested repeatedly. However, the information provided does not tell you how stored results display date and time or what the app's detailed history screen looks like.
If family members share the device, the results themselves can be personal information. Agreeing in advance who uses the device and how much of the stored results each person can see reduces the chance that the record feature is misunderstood as a means of judging each other's driving. It is more appropriate to see app integration and storage not as features that make results more definitive, but as supporting features that organize the testing process.
The goal of first use is not operating skill
The items to learn first are the ready screen, the test sequence, the result units, the error indicators, and where to get help. The AF-40BT also has battery and calibration reminder features, but storage conditions, calibration timing, and checks for device faults should be handled separately as maintenance. Calibration is the process of checking how the instrument's reading relates to a reference value; it does not mean the same thing as an adjustment where the user presses buttons to change settings, or a repair.
The number from a personal breathalyzer is not a reason to hurry out the door; it is reference information that makes the driving decision more careful. On days when you have not read the model-specific instructions or the meaning of the screen is unclear, the safe way to use this device is to choose a way to travel that does not involve driving, rather than pressing more buttons to force a conclusion.
※ Self-check results from our products are provided as reference information only. Actual enforcement standards and test methods may differ by agency and equipment, so self-check results and enforcement results may differ, and the company accepts no responsibility for enforcement results.
