Article
Car Tilt Alarm
Protect your alloy wheels
The car alarm described here detects changes in the tilt angle of the vehicle in which the alarm is installed. It is set off when the change in the angle exceeds a threshold (adjustable) for too long (5 seconds). Short of cutting the power to it, the only way to stop the alarm is to put the car back to its initial angle. The change in angle to which the alarm is sensitive can be adjusted from 0 to 25°.
Materials
Gerber file
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PCB
Extra info / Update
Technical Specifications
- trigger angle: 0–25°
- operating time adjustable 0–165 s;
- two activation modes: intermittent @ 0.5 Hz or continuous
- built-in installation aid.
- trigger angle: 0–25°
- operating time adjustable 0–165 s;
- two activation modes: intermittent @ 0.5 Hz or continuous
- built-in installation aid.
Component list
Resistors
R1 = SIL array 8x 4.7kOhm
R2,R3,R4 = 1kOhm
R5 = 330Ohm
R6 = 4.7kOhm
R7 = 10kOhm
Capacitors
C1 = 470µF 25V axial electrolytic
C2 = 100µF 25V axial electrolytic
C3, C6 = 100nF
C4, C5 = 15pF ceramic
Semiconductors
IC1 = PIC16F877-20/P, programmed
IC2 = 7805
IC3 = ULN2803A
IC4 = 4N25 or equivalent
D1 = 1N4001
D2–D9, D12–D15 = 1N4148
D10, D11 = LED, 3mm
Miscellaneous
X1 = 8MHz quartz crystal, low profile
JP1–JP4, JP5–JP8, JP9–JP12 : 8-way (2x4) DIL pinheader with jumpers
S1 = 4-way DIP switch block
RE1 = relay, 12V coil, miniature, 2RT
K1,K2,K5,K6 = 3-way SIL pinheader, lead pitch 2.54mm (0.1")
Support for on/off LED, colour and diameter to personal requirements
2-axis accelerometer module with ADXL322 (Lextronic France # ADXL322)
Fuse and in-line fuseholder for vehicles
Standoffs, screws, case, etc.
R1 = SIL array 8x 4.7kOhm
R2,R3,R4 = 1kOhm
R5 = 330Ohm
R6 = 4.7kOhm
R7 = 10kOhm
Capacitors
C1 = 470µF 25V axial electrolytic
C2 = 100µF 25V axial electrolytic
C3, C6 = 100nF
C4, C5 = 15pF ceramic
Semiconductors
IC1 = PIC16F877-20/P, programmed
IC2 = 7805
IC3 = ULN2803A
IC4 = 4N25 or equivalent
D1 = 1N4001
D2–D9, D12–D15 = 1N4148
D10, D11 = LED, 3mm
Miscellaneous
X1 = 8MHz quartz crystal, low profile
JP1–JP4, JP5–JP8, JP9–JP12 : 8-way (2x4) DIL pinheader with jumpers
S1 = 4-way DIP switch block
RE1 = relay, 12V coil, miniature, 2RT
K1,K2,K5,K6 = 3-way SIL pinheader, lead pitch 2.54mm (0.1")
Support for on/off LED, colour and diameter to personal requirements
2-axis accelerometer module with ADXL322 (Lextronic France # ADXL322)
Fuse and in-line fuseholder for vehicles
Standoffs, screws, case, etc.
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