| Specification: |
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| The process should register the input signal and therefore control different light sequences. It should be able to create a number of sequences responding to how many claps have occurred in a certain time span.
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| Alternative Design: |
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| Using the input system it can control different light sequences using logic. The use of three flip flops will count the number of claps and therefore control, which light is on. An idea for the circuit is shown below.
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| However this circuit is unnecessarily complicated when a pic can be used that will control the outputs with a simple program. The pic will also allow the LED�s to flash in different sequences at different speeds allowing a more aesthetically pleasing product.
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| Final Design: |
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| Using a counter the number of claps can be counted from the input of the microphone system. The counter outputs shall be connected to the inputs of the pic. The pic then shall be programmed to produces four different light sequences, as shown on the following page. There shall only be four light sequences due to the limited number of input pins on the pic and the limited number of lines on the pic program. However a larger pic would increase the number of inputs but there is still the limited number of lines on the pic program. The pic shall be programmed using chip factory software and then downloaded to the pic via a serial port. The outputs of the pic will then control the output system of LED�s. One output shall be taken to reset the counter after a certain time, which is shown on the following program. This enables the person to clap the exact number to determine the program number.
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Chip Factory Program
Title: Fibre Optic Christmas Tree
Written by: Adrian Townsend
PIC Type: PIC16F84a
00 high 1 Key:
01 wait 020 Output 0: Reset For Counter
02 low 1 Output 1: Blue Led
03 high 2 Output 2: Yellow Led
04 wait 020 Output 3: Red Led
05 low 2 Output 4: Green Led
06 high 3 Output 5: White Led
07 wait 020
08 low 3
09 high 4
10 wait 020 Light Sequence 2
11 low 4
12 high 5
13 wait 020
14 low 5
15 if 0 on goto 84 Input check at the end of
16 if 2 on goto 21 each sequence to either
17 if 3 on goto 48 carry on with same sequence
18 high 0 or move to a different one.
19 low 0
20 goto 00
21 high 5 Light Sequence 3
22 wait 010
23 low 5
24 high 3
25 wait 020
26 low 3
27 high 2
28 wait 010
29 low 2
30 high 1
31 wait 020
32 low 1
33 high 4
34 wait 010
35 low 4
36 high 5
37 wait 020
38 low 5
39 high 1
40 wait 010
41 low 1
42 if 0 on goto 84
43 if 1 on goto 00
44 if 3 on goto 48
45 high 0 Resets Counter using output 0
46 low 0
47 goto 21
48 high 1 Light Sequence 4
49 wait 010
50 low 1
51 high 3
52 wait 010
53 low 3
54 high 2
55 wait 010
56 low 2
57 high 4
58 wait 010
59 low 4
60 high 5
61 wait 010
62 low 5
63 high 4
64 wait 010
65 low 4
66 high 3
67 wait 010
68 low 3
69 high 1
70 wait 010
71 low 1
72 high 2
73 wait 010
74 low 2
75 high 1
76 wait 010
77 low 1
78 if 0 on goto 84
79 if 1 on goto 00
80 if 2 on goto 21
81 high 0
82 low 0
83 goto 48 Light Sequence 1
84 high 1
85 wait 030
86 low 1
87 high 5
88 wait 040
89 low 5
90 high 3
91 wait 030
92 low 3
93 if 1 on goto 00
94 if 2 on goto 21
95 if 3 on goto 48
96 high 0
97 low 0
98 goto 84
99
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| Reasons For Choice: |
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| The second design was chosen, as it was simpler to design and produced a better end result. The pic allowed the ability to make flashing and continuously changing light sequences. The first design only allowed the change of the outputs, which was not aesthetically pleasing.
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| Testing: |
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| The counter and pic were built separately to the input source therefore allowing the use of a push switch to test the process. The input pin on the counter was connected to the push switch. If the input was taken from the input system and any problems occurred this meant the input system would also have to be checked. To test if the counter was working a logic probe was used to test if the pins were high or low according to the count.
The pic was tested on the chip factory program and on a test board before inserting on the circuit. The pic was positioned and LED�s were added to the outputs to visually check the full circuit was working. However one problem was found. When the counter and pic were fully set-up the counter was not resetting properly. Using a multimeter it was found that when the counter reached the forth count it would not reset itself, as there was not enough voltage reaching the reset pin. An attempt to solve the problem was using a transistor to increase the voltage however this only increased the voltage fractionally. More complicated attempts of a logic system would solve the problem however a simple solution of placing a push switch to the reset allows one to manually reset the counter. The problem is not severe as the pic resets the counter after a short time period therefore the manual reset is not entirely necessary but improves the practicality of the circuit.
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| Contents |
Research |
System Designs |
Design Specification |
Input Sub-System | Process Sub-System |
Output Sub-System |
Final Circuit Design |
Evaluation |
The Project. |
