Download Radio Tag For Item Tracking - Introduction

School of Electronic, Communication and Electrical Engineering
BEng Final Year Project Report
or behave unpredictably in other ways. The decoupling capacitor filters the power fluctuations
and provides a stable power supply for the chip
[14]
. Therefore, a 100uF electrolytic capacitor
was connected between the all the VDD pins and wired to ground, as shown in Fig 3-5 below.
Figure 3-5 Decoupling a PIC 16F88 MCU
The circuit design involved connecting an 8 pin DIP switch (see figure 3-6 below) to the
microcontroller. As described in Section 2.1 the DIP switch is used to input the Tag serial
number into the microcontroller.
Figure 3-6 Radio Tag Block Diagram
Since the microcontroller would read the DIP switches as individual binary numbers, the 8
8
Switches could provide us with a possible 2 – 1 = 255 different tag numbers. A pin map of
the DIP switch with the microcontroller ports and their equivalent decimal value is given in
figure 3-7 below.
Figure 3-7 Pin Map for the Tag No using 8 Pin DIP Switch
The DIP switch is connected to RA0, RA1, RA2, RA3 and RB0, RB1, RB2, RB3 pins of the
microcontroller. The input of the DIP switch is connected in parallel to the 5V Power Supply to
the microcontroller, providing 5V to each of the switches. If any of the 8 switches is turned to
Ramiz Ahmed / Radio Tag for Item Tracking
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