Specifications

45
events are taking place. The more attention we can bring to the box the more better it is
in the safety and well being of the individual using it as well as the machine itself.
Adding a speaker will be very inexpensive as well as very valuable in the event of failure
as well as in the event of important events that might take place.
4.2.3 Displays
Our display will be programmed using C/C++ programming language. There will be
many functions to control different types of messages that will be displayed to the user.
One of these functions will show what the status of the battery is. This function will be
called by main and will be used when the mode button is pressed. It will also cycle
through other functions, which will control different things. This function will contain an
algorithm that will calculate how much time is remaining until empty. The chart below
will explain the method we are using to show where the battery is. Since we are using a
car battery it is a 12 Volt battery and will be following these specs to get the percent of
the battery left.
Percentage of Battery Charge Remaining
Battery Terminal Voltage
0
10.5
5
10.63
10
10.76
15
10.89
20
11.02
25
11.15
30
11.28
35
11.41
40
11.54
45
11.67
50
11.8
55
11.93
60
12.06
65
12.19
70
12.32
75
12.45
80
12.58
85
12.71
90
12.84
95
12.97
100
13.1
Figure 34 - Voltage vs. percent of charge left
When the battery is full it will be a little above 12 volts. As the battery loses charge the
voltage will drop causing the percent of battery left to change. This will be sent into the
microcontroller in real time such that the microcontroller can display that on the LCD