This blood alcohol calculator is designed to calculate the approximate blood alcohol content (“BAC”) for the average person, depending on a number of variables. It works by adding the amount of alcohol ingested by a person over time and subjecting the total amount ingested to an elimination factor as the alcohol is metabolized.
Please refer to the two wireframes in the attached zip file. Note: I don't know whether these arrangements and choices of controls comply with Apple's user interface guidelines and will count on you to suggest changes if they do not. The wireframes are not exact – I can make the end product prettier when the project is finished.
On the first page of the app, the user will select from variables which will become constants for this user session. These variables are:
Gender - Male or Female. If Male is selected, we will use Male Formula (see below). If Female is selected, we will use Female Formula (see below).
Height - To be entered in feet and inches but converted by the app to meters with two significant digits.
Weight - To be entered in pounds but converted by the app to kilograms with two significant digits.
The Reset button removes all data so that the user can begin anew.
The FAQ button takes the user to an html page which will explain the app.
The Next button takes the user to the second page of the app.
The second page of the app includes these features:
BAC – Will display the current BAC. When the user first uses the app (in other words, enters gender, height and weight) BAC will show 0.00. All output will be in the form [url removed, login to view] where each x is a digit.
Time – Displays elapsed time since first drink in hours and minutes. When the user first uses the app (in other words, enters gender, height and weight) time will equal zero. Elapsed time will begin when one of the segment controls (Beer/Wine/Liquor) is touched.
Recalculate – This button will cause the BAC and Time outputs to update.
Slider bar – User selects how full the user's stomach is (this affects absorption rate of alcohol). The scale between Empty and Full should be linear. The values for Empty and Full are set forth below.
Segmented control - Pick a Drink – Beer, Wine and Liquor have specific values, as set forth below.
Reset – Removes all data so that the user can begin anew and returns the user to the first page of the app.
FAQ - Takes the user to an html page which will explain the app.
When a user touches Beer/Wine/Liquor, a calculation is made of BAC. This calculation is based on the user's gender, height and weight, as well as on how full the user's stomach was when he drank each drink, what kind of drink (and therefore the amount of ethanol) he drank, and the elapsed time since each drink. Every time Beer/Wine/Liquor is touched, a new calculation is made. The BAC level for the new drink is added to the BAC level from all previous drinks and then that total amount of BAC is subjected to a decay or elimination factor to calculate the current BAC level. “Time” shows the elapsed time since the first drink.
If the user touches only the Recalculate button, the BAC is updated, with the only change being to elapsed time because no other inputs are changed.
Actual formulas are proprietary but will be supplied to winning bidder.