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

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. Connect Vcc with RESET ( Pin 16) by a 1 kΩ resistor. square wave keypad controller signals 1k GND

Microcontroller Result: Period: 16 µs Frequency = 1/period = 62.5 kHz Vpp = 3.3 V 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.

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.

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 Power Control signalIf the control signal is logic-1, the BJT is on. Consequently, the speaker is on. 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.

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 Control signal 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.

Motor Requirement: 1. Current go through motor should be within the range of 1+/ A when microcontroller is giving logic-1. Result: Current: 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 Power Control signal If the control signal is logic-1, the MOSFET is 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.

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 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 +/ 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 = 9 J W = 1841 J 12 V battery of 55 mAh (20times/day) 7 days 1.5 days

Functional Tests

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 functionEngineering reason CC3200 Chip on boardProgrammer Wifi functionThe replaced MSP 430 has no wifi module Acceptable sizeThe 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