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Automatic Hotel Check-in
and out System
PROJECT #31
Tingting Dang, Tianyuan Feng, Yuncong Hao
Introduction
Traditional Hotel Check in Check out System Problems
• Labor Cost
• Time Consuming
• Privacy Issue
Objective
• Less front desk employees needed
• Reduce hotel costs
• Reduce guests waiting time to get checked-in
• Protect Personal information
Functions & Features
• Keypad for user input
• Green LED lights when entering correct key input
• Lock opens when entering correct key input
• Red LED lights when entering wrong key input
• Buzzer sounds when entering wrong key input
System Overview
System Overview
• User enters keycode through the
keypad into the microcontroller.
• Microcontroller determines the
correctness of the keycode.
• Microcontroller generates a square
wave to the power management circuit
for 2s after keycode is entered, and give
out control signal to LEDs, speaker, and
motor (lock).
• If the keycode is correct, the lock
(motor) opens and green LED lights.
• If the keycode is incorrect, the buzzer
sounds and red LED lights.
Microcontroller
• Recognize key stoke from keypad.
• Send control signals to green LED, red LED,
speaker and motor (lcok).
• Generate a Vpp =3.3 V 60 kHz square wave to
power management circuit.
Microcontroller
RESET pin ( Pin 16) is active low.
Microcontroller keeps at reset state,
unless drive the RESET pin to high
voltage.
square wave
Connect Vcc with RESET ( Pin 16) by a
1 kΩ resistor.
GND
1k
keypad
keypad
controller signals
Microcontroller
Requirement:
1. Output high voltage (logic-1): 3.3+/-0.1 V
2. Output low voltage (logic-0): less than 0.1 V
3. Generate a Vpp =3.3+/-0.1 V 60+/-5 kHz
square wave to power management circuit.
Result:
Period: 16 µs
Frequency = 1/period = 62.5 kHz
Vpp = 3.3 V
Software
Keypad
• 4*4 matrix keypad
• User enters keycode by keypad.
• Keypad sends keystrokes to microcontroller.
Keypad
8 pins: 4 pins for row wires (input) and another 4
pins for column wires (output)
The column wire and the row wire isn’t in contact,
if no key is pressed. If a key is pressed, the
corresponding column wire and row wire are in
contact.
The keypad is controlled by a microcontroller.
The outputs of the microcontroller go high one by
one in cycle.
http://pcbheaven.com/wikipages/How_Key_Matrices_Works/
Keypad
Requirement:
1. Output logic-1 voltage should be within
the range of 3.3+/-0.1 V.
2. Output logic-0 voltage should be below
0.3 V.
Result:
V = 3.30 V (left figure)
V = less than 0.3V ( right figure)
Speaker
• Controlled by microcontroller.
• If the keycode entered isn’t correct, the
speaker gives out beeping sound.
Speaker
If the control signal is logic-1, the BJT is on.
Consequently, the speaker is on.
Control signal
If the control signal is logic-0, the BJT is off.
Consequently, the speaker is off.
A 1 kΩ resistor and a diode is parallel with the
speaker to protect the speaker from reverse
current.
Power
Speaker
Requirement:
1. Current go through speaker should be
within the range of 5+/-1 mA and the sound
produced by speaker should be within the
range of 70+/-5 dB when the controller is
giving logic-1.
Result:
Current: 13.9 – 9 (current through red LED) =
4.9 mA
Loudness = 70 dB
Speaker
Requirement:
2. Current go through Speaker should be
below 1 mA and the sound produced by
speaker should be below 10 dB when
controller is giving logic-0.
Result:
Current: less than 1 mA
Loudness = less than 10 dB
Motor
• Motor: lock style solenoid.
• Controlled by microcontroller
• If the keycode entered is correct, the
lock (motor) open.
Motor
Power
If the control signal is logic-1, the BJT is on.
Consequently, the lock (motor) is on.
If the control signal is logic-0, the BJT is off.
Consequently, the lock (motor) is off.
A diode is parallel with the lock (motor) to protect
the lock (motor) from reverse current.
Control signal
Motor
Requirement:
1. Current go through motor should be
within the range of 1+/- 0.15 A when
microcontroller is giving logic-1.
Result:
Current: 0.998 A
Motor
Requirement:
2. Current go through motor should be
below 0.2 mA when microcontroller is
giving logic-0.
Result:
Current: less than 0.2 mA
LED
• Controlled by microcontroller
• If the keycode entered is correct,
green LED light.
• If the keycode entered is incorrect, red
LED light.
LED
If the control signal is logic-1, the MOSFET is Control signal
on. Consequently, the LED is on.
If the control signal is logic-0, the MOSFET is
off. Consequently, the LED is off.
A 270 Ω resistor is in series with the LED to
reduce.
Power
LED
Requirment:
1. The LED turns on and the current
through the LED should be within the
range of 9+/-1 mA when controller signal
voltage at logic-1.
2. The LED stays off and the current
through the LED should be below 1 mA
when controller signal voltage at logic-0.
Power Management
DC-DC Buck Converter (12V – 5V)
This module will convert a 12V DC input to a 5V
• Controller: M430G2553
DC output. This 5V voltage will be used as the
• Gate Driver: IRS 2184
input voltage of our speaker and LED modules.
• Cin : 47 uF
• D1 : 1N4001
• Inductor: 300 uH
• Cout: 10 uF
•
• Load: 215 +/- 35 ohm
•
• Efficiency: 80%
•
Power
Requirements:
• 5 +/- 0.3 V voltage output at current load of 65mA
• Voltage ripple less than +/- 0.15 V
• Efficiency greater than 75%
Test Result:
• 5.08 V voltage output mean value at load of 65mA
• Voltage ripple 0.181V
• Efficiency (80%,86%)
Battery Life
Buck Converter
Linear Regulator
Daily loss during sleeping mode
W = 0J
P = (12 – 5 ) * 3m = 21 mW
W = 21m * 3600 *24 = 1814J
Daily loss during running mode
W = 12V*65mA *2s*20/0.75 W = 12 *65mA*2*20/0.25
= 9J
= 27 J
Overall Daily loss
W=9J
12 V battery of 55 mAh (20times/day) 7 days
W = 1841 J
1.5 days
Functional Tests
https://www.youtube.com/embed/wXHN6aMug2Y
Success and Challenge
Success:
All modules are worked well.
Missing the Wifi function.
Challenge:
CC3200 lanuch pad
Metal pin output 12V, the power indicator LED is not luminated.
Power efficiency
Failed Verifications and Reasons
Failed function
Engineering reason
CC3200 Chip on board
Programmer
Wifi function
The replaced MSP 430 has no wifi module
Acceptable size
The conflict between power efficiency and size
Future Work
• Add the Wifi function
• Optimize the circuit, reduce the size
• Contact local hotel, adjust depend on their request