APPENDIX A - BLOCK DIAGRAMS
Figures A1 is a block diagram and general design overview of the smoke detector unit.
Figure A1 Smoke Detector Unit
Smoke Detector Unit
Transmitter
Tone Generator /
Speaker
Receiver
PIC
Microcontroller
Smoke Sensor
Temperature
Sensor
A.1
Low Battery
Sensor
APPENDIX B – FLOW DIAGRAMS
Figures B1 is the PIC microcontroller flow diagram. It illustrates the flow of the program code
and the priority status of the smoke detector’s alarms.
Figure B1 PIC Microcontroller Flow Diagram
Temperature Sensor
Temperature threshold of
125°F reached?
Yes
No
Receiver
RF signal received from
another detector’s transmitter?
Yes
No
Smoke Sensor
Smoke detected?
Yes
No
Low Battery Sensor
Battery measured below 3.5V?
Yes
No
No
PIC Microcontroller
Temperature sensor, receiver,
smoke sensor, or low battery
sensor has been set off?
Yes
Transmitter
A.2
Tone Generator /
Speaker
APPENDIX C - DIAGRAMS
Appendix C illustrates diagrams pertaining to the various modules of the smoke detector unit.
Figure C1 Smoke Sensor T-Shaped Chamber without Smoke Present
Figure C2 Smoke Sensor T-Shaped Chamber with Smoke Present
Figure C3 Smoke Sensor Ionization Chamber
A.3
APPENDIX D – SCHEMATICS
Appendix D illustrates the schematics of all the hardware components and modules—PIC
microcontroller, low battery sensor, temperature sensor, smoke sensor, tone generator,
transmitter, and receiver.
Figure D1 PIC Microcontroller and Low Battery Sensor Schematic
R1 46K
01-MCLR
32-Vdd
02-RA0
31-Vss
03-RA1
25-RC6
To 09-CD4052BN #1
From 276-143
04-RA2
24-RC5
To 10-CD4052BN #1
From 18-RMX-900-HP3
05-RA3
23-RC4
To 10-CD4052BN #2
From 02-LM235AH
11-Vdd
12-Vss
13-OSC1
5Vdc
To 13-RMX-900-HP3
To 09-TMX-900-HP3
To 12-TMX-900-HP3
15-RC0
16-RC1
17-RC2
PIC16F877A
01-Vcc
02-Out
ECS-100AC
6.000MHz
03-GND
Figure D2 Temperature Sensor Schematic
To PIC Pin 2(RA0/AN0)
LM235AH
R1
V-
V+
To Vcc
1k
ADJ
R2
10k
A.4
Figure D3 Mechanical Schematic of the Smoke Sensor T-Shaped Chamber
1.5 in.
0.6 in.
0.6 in.
Figure D4 Smoke Sensor Schematic
R1
2.6K
V1
5Vdc
Infrared Emitter
To PIC16F877A(04-RA2)
Infrared
276-143
A.5
Figure D5 Tone Generator and Speaker Schematic
V+
V-
R4
SPEAKER
R5
Timer
7
5
4
6
2
8
DSCHG
47k
OUT
3
120k
33k
R1
CV
RST
THR
TRG
R3
GND
VCC
1
15k
56k
R2
3k
LM555
Mux #2
Mux #1
R6
12
14
15
11
1
5
2
4
10
9
6
7
16
X0
X1
X2
X3
X
Y
13
3
12
14
15
11
1
5
2
4
Y0
Y1
Y2
Y3
GND 8
4052
3
EN
7
16
C4
CAP 0.1uF
13
A
B
6
EN
X
Y
Y0
Y1
Y2
Y3
10
9
A
B
VEE
VDD
X0
X1
X2
X3
VEE
VDD
GND
8
4052
C3
CAP 0.1uF
To Vcc
C1
From PIC: Pin 23 (RC4/SDI/SDA)
CAP 0.01uF
From PIC: Pin 25(RC6/TX/CK)
C2
From PIC: Pin 24(RC5/SDO)
CAP 0.01uF
A.6
Figure D6 Transmitter and Receiver Schematic
Testing Purposes Only
RMX-900-HP3
9-NC
18-DATA
17-Audio.
To PIC: Pin 5 (RA3/AN3)
16-VCC
C2
14-RSSI
2-GND
13-PDN
CAP 0.1uF
To PIC: Pin 15 (RC0)
10-CSO
R1
ANT2
ANTENNA
11-CS1
10 Ohm
C4
12-CS2
Power
1-Ant
3->8 - GND
15-Mode
GND
CAP 10uF
R2
10 Ohm
C3
CAP 10uF
ANT1
ANTENNA
TMX-900-HP3
Power
2-Ant
8-Vcc
GND
10-DATA
From PIC: Pin 17(RC2)
3-CSO
4-CS1
5-CS2
9-Mode
6-CTS
C1
1 - GND
7-PDN
From PIC: Pin 16(RC1)
CAP 0.1uF
To Vcc
A.7
APPENDIX E – PIC MICROCONTROLLER CODE
Table E1 is the actual PIC microcontroller program and code.
Table E1 PIC Microcontroller Code
/*****************************************************************************
*\
*
*
*
PREPROCESSOR DIRECTIVES
*
*
*
\*****************************************************************************
*/
//#include <18F452.h>
#include <16F877A.h> // <-- This is the type of PIC you're using.
// Other supported PICs are in:
// C:\Program Files\PICC\Devices
//#device ICD=TRUE
#device *=16 ADC=10
// Use 16-bit pointers, use 10-bit ADC
#fuses HS
// You may or may not want some of these ....
#fuses NOWDT
#fuses NOPROTECT
#fuses NOLVP
#fuses NODEBUG
#fuses NOPUT
#fuses NOBROWNOUT
#use delay(clock=6000000)
// What speed clock do you want today?
// These require use of Set_Tris_x()
#use fast_io(A)
#use fast_io(B)
#use fast_io(C)
//#use fast_io(D)
// End Preprocessor Directives
// Always a good idea to write clean code, makes changes easy
//#include "Include\Compiler.h"
//#include "Include\Globals.h"
// A/D + Buttons
#define MY_TRISA 0b11111111
#define MY_TRISB 0b11111111
#define MY_TRISC 0b00000000
#define MY_TRISD 0b00000000
#define FOREVER
1
A.8
// RX pins
#define RX_PD
PIN_C0 // out (active low)
#define RX_DATA PIN_B0 // in
#define RX_CHS0 PIN_D3 // out
#define RX_CHS1 PIN_D4 // out
#define RX_CHS2 PIN_D5 // out
// TX pins
//#define TX_CTS
PIN_B1 // in
#define TX_PD
PIN_C1 // out (active low)
#define TX_DATA PIN_C2 // out
#define TX_CHS0 PIN_D0 // out
#define TX_CHS1 PIN_D1 // out
#define TX_CHS2 PIN_D2 // out
void initADC(void);
/*****************************************************************************
*\
*
*
*
MAIN ROUTINE
*
*
*
\*****************************************************************************
*/
#pragma zero_ram
// Interesting command ....
void main( void)
{
int16 ADC_0;
int16 ADC_1;
int16 ADC_2;
int16 ADC_3;
int16 temp;
int16 battery;
int16 smoke;
int16 receiver;
ADC_0 = 0;
ADC_1 = 0;
ADC_2 = 0;
ADC_3 = 0;
temp = 665;
battery = 716.8;
smoke = 1007.616;
receiver = 40.96;
delay_ms(500);
// wait for voltages to stablize
Set_Tris_A(MY_TRISA); // Port A's I/O
Set_Tris_B(MY_TRISB); // Port B's I/O
A.9
Set_Tris_C(MY_TRISC); // Port B's I/O
Set_Tris_D(MY_TRISD); // Port B's I/O
initADC();
output_low(TX_PD);
output_low(RX_PD);
delay_ms(100);
output_high(TX_DATA);
output_high(RX_DATA);
while(FOREVER)
{
delay_us(50);
set_adc_channel( 0 );
delay_us(10);
ADC_0 = read_adc();
delay_us(50000);
// Read in the value of the ADC
if (ADC_0 > temp)
{
output_low(PIN_C4);
output_low(PIN_C5);
output_high(PIN_C6);
output_low(RX_PD);
delay_ms(100);
output_high(TX_PD);
delay_ms(100);
output_low(TX_DATA);
}
else
{
set_adc_channel( 2 );
delay_us(10);
ADC_2 = read_adc();
delay_us(50000);
// Read in the value of the ADC
if (ADC_2 > smoke)
{
output_high(PIN_C4);
output_low(PIN_C5);
output_high(PIN_C6);
output_low(RX_PD);
delay_ms(100);
output_high(TX_PD);
delay_ms(100);
output_low(TX_DATA);
}
else
A.10
{
output_low(TX_PD);
delay_ms(100);
output_high(RX_PD);
delay_ms(100);
set_adc_channel( 3 );
delay_us(10);
ADC_3 = read_adc();
// Read in the value of the ADC
delay_us(50000);
if ( ADC_3 < receiver )
{
output_low(PIN_C4);
output_high(PIN_C5);
output_low(PIN_C6);
}
else
{
output_low(RX_PD);
delay_ms(100);
set_adc_channel( 1 );
delay_us(100);
ADC_1 = read_adc();
// Read in the value of the ADC
delay_us(50000);
if (ADC_1 < battery)
{
output_low(PIN_C4);
output_low(PIN_C5);
output_low(PIN_C6);
}
else
{
output_high(PIN_C4);
output_high(PIN_C5);
output_high(PIN_C6);
//output_high(RX_DATA);
}
}
A.11
}
}
}
}
// End Main Routine
// Purpose:
Initializes ADC
// Precondition: None
// Postcondition: ADC is configured
void initADC(void)
{
setup_adc_ports(ALL_ANALOG); //
setup_adc(ADC_CLOCK_INTERNAL);
}
A.12
APPENDIX F – TEST DATA
Appendix F contains various test data from different modules of the smoke detector unit.
Figure F1 Smoke Sensor Resistance at 100 ohms
R1 = 100 ohms
Voltage @ Collector = 4.994V
5.2
5.15
Volts
5.1
5.05
5
4.95
4.9
-0.0003
-0.0002
-0.0001
0
0.0001
0.0002
0.0003
Seconds
Figure F2 Smoke Sensor Resistance at 470 ohms
R1 = 470 ohms
Voltage @ Collector = 4.97V
5.04
5.02
Volts
5
4.98
4.96
4.94
4.92
-0.0006
-0.0004
-0.0002
0
0.0002
0.0004
0.0006
Seconds
Figure F3 Smoke Sensor Resistance at 750 ohms
R1 = 750 ohms
Voltage @ Collector = 4.967V
5.04
5.02
5
Volts
4.98
4.96
4.94
4.92
4.9
4.88
-0.00000003 -0.00000002 -0.00000001
0
Seconds
A.13
0.00000001 0.00000002 0.00000003
Figure F4 Smoke Sensor Resistance at 2.6K ohms
R1 = 2.6K ohms
Voltage @ Collector = 4.88V
4.96
4.94
4.92
Volts
4.9
4.88
4.86
4.84
4.82
4.8
4.78
-0.00000003 -0.00000002 -0.00000001
0
0.00000001 0.00000002 0.00000003
Seconds
Figure F5 Smoke Sensor Resistance at 5.1K ohms
R1 = 5.1K ohms
Voltage @ Collector = 4.77V
4.88
4.86
4.84
Volts
4.82
4.8
4.78
4.76
4.74
4.72
4.7
4.68
-0.00000003 -0.00000002 -0.00000001
0
0.00000001 0.00000002 0.00000003
Seconds
Figure F6 Transmitter and Receiver Wireless Range Data
RSSI
3
2.5
RSSI
2
1.5
Series1
1
0.5
0
0
10
20
30
40
Distance
A.14
50
60
70
APPENDIX G – COST
Appendix G delineates the cost of the smoke detector unit and the cost of labor.
Table G1 Cost of Parts and Overall Cost of the Smoke Detector Unit
Part #
Manufacturer
Description
LM235AH
National
RMX-900HP3
TMX-900HP3
ANT-916PW-LP
PIC16F877A
276-142, 276143
PVC Pipe
MN1604B1Z
Duracell
LM555CM
National
74ALS253AN
ECE Parts
Store
CUI
ECE Parts
Store
GC0401K
Misc.
(resistors,
capacitors,
etc.)
Price
Linx
Temperature
Sensor
Receiver
Module
Needed For
Temperature
Sensor
Receiver
Linx
Transmitter
Transmitter
$29.45
Linx
Antenna
$1.79
Microchip
Radio Shack
PIC
LED and
Phototransistor
PVC Pipe
Receiver /
Transmitter
PIC
Smoke
Sensor
Smoke
Sensor
Smoke
Detector
Tone
Generator
Tone
Generator
Speaker
Testing
Purposes
TOTAL
$100.64
Home Depot
9V Alkaline
Battery
Timer
4-to-1 Dual
MUX
Speaker
Resistors
Table G2 Cost of Labor
Hourly
Rate
$50 per
hour
Total
Hours
140
hours
Number of
Persons
2 persons
A.15
Total Labor
Cost
$14,000
$5.49
$43.40
$4.94
$3.29
$2.99
$1.99
$0.64
$0.79
$2.99
$2.88
APPENDIX H – PICTURES
Figure H1 shows a photo of the smoke detector unit in its completion and entirety.
Figure H1 Final Smoke Detector Unit
A.16
REFERENCES
[1]
M. Brain, “How Smoke Detectors Work,” June 1995, http://home.howstuffworks.com/smoke.ht
m.
A.17