The Kick Buttons will be designed for residents who have partial mobility of their legs and can use their legs to kick objects. The kick button panel will have 5 kick buttons, allowing the resident to control the entire home automation system using them. We will be creating this kick-button system for someone who uses a wheelchair and has limited leg motor control. The buttons will be designed so that the caretaker can shift their location (by sliding) to a position that is convenient for the resident.

Figure XX: Figure title

Requirements

Initial Design Requirements:

1. The kick buttons must be easy to activate, requiring minimal force to be kicked.
2. They should be mounted on a raised platform that can be positioned within easy-kicking distance from the resident’s wheelchair.
3. The buttons need to light up whenever they are kicked.
4. The buttons must transmit data wirelessly to the connected smart mobile device.
5. The power usage for the button system should not exceed 12 V or 200 mA.
6. The button system should be powered with a 12V input.

After discussion with the product development team, the initial design requirements were broken down into the following technical requirements:

Technical Design Specifications:

Setup:

• The button system (5 buttons and the circuitry) shall be powered using a 12 V supply
• The 5 buttons shall be on a custom slanting mount/footrest.

Mechanical Design Requirements:

Figure XX: Figure title

• The metal strap should not hit the surface of the optical switch.
• The metal strap shall cut the laser of the optical switch once the button is pushed
• In the equilibrium position, the metal strap should not be cutting the laser of the optical switch.
• After pressed, the button shall return to the equilibrium position
• The button shall be able to hold the LED driving circuitry.

Electrical functionality:

Figure XX: Figure title

• The optical switch, whose voltage is regulated by LM 7805, shall not receive more than 5.5 V.
• The current in the LED driver circuit shall not exceed 40 mA.
• The GPIO input to the microcontroller shall not be more than 3.8 V.

Individual Button Functionality:

• On pressing the button, the microcontroller shall detect a logic high.
• On pressing the button, the LEDs on the button should light up.
• On pressing the button, the microcontroller should transmit “ON_buttonNumber” message to the tablet via bluetooth. The default message for each button on the tablet should be “OFF_buttonNumber”

Overall Requirements:

Figure XX: Figure title

• The microcontroller shall compile a complete string indicating the state of each button: ON_1 OFF_2 OFF_3 OFF_4 ON_1
• The microcontroller shall transmit a complete string (as defined in the above point) over Bluetooth to the tablet.
• The system shall be responsive to rapid button presses.

General Requirements:

• The kick buttons must be easy to activate, requiring minimal force to be kicked.
• The power usage for the button system should not exceed 12 V or 200 mA.

 

Test Plan

Mechanical Design Requirements

1. Interaction with Optical Switch Surface (T1)

• Requirement: The metal strap should not hit the surface of the optical switch.
• Test Method: Visually inspect and measure the clearance between the metal strap and the surface of the optical switch in all button positions.
• Acceptance Criteria: There should be a minimum clearance of 1 mm (to be defined as per design) between the metal strap and the optical switch surface in both pressed states.
• Test Equipment: Caliper or other precision measurement tool.
• Result: PASS/FAIL

2. Laser Interruption upon Button Press (T2)

• Requirement: The metal strap shall cut the laser of the optical switch once the button is pushed.
• Test Method: Press the button and monitor the optical switch to confirm that the laser is interrupted by the metal strap.
• Acceptance Criteria: The laser of the optical switch should be interrupted once the button is fully pressed. (See change in output from the button)
• Test Equipment: voltmeter.
• Result: PASS/FAIL

3. Laser Continuity in Equilibrium Position (T3)

• Requirement: In the equilibrium position, the metal strap should not be cutting the laser of the optical switch.
• Test Method: Set the button in its equilibrium position and check if the laser beam of the optical switch remains unblocked.
• Acceptance Criteria: In the unpressed/equilibrium state, the laser of the optical switch should not be interrupted by the metal strap. (See that output from the button is unchanged)
• Test Equipment: voltmeter.
• Result: PASS/FAIL

4. Button Return to Equilibrium Position (T4)

• Requirement: After being pressed, the button shall return to the equilibrium position.
• Test Method: Manually press the button multiple times and observe whether it reliably returns to the equilibrium position each time.
• Acceptance Criteria: The button should return to its original (equilibrium) position after release.
• Test Equipment: Manual testing, caliper for measurement if needed.
• Result: PASS/FAIL

5. LED Circuitry Accommodation (T5)

• Requirement: The button shall be able to hold the LED driving circuitry.
• Test Method: Insert the LED driving circuitry into the designated compartment within the button. Check for proper fit, alignment, and secure positioning.
• Acceptance Criteria: The LED circuitry should fit securely within the button, with no movement or obstruction.
• Test Equipment: LED driving circuitry module.
• Result: PASS/FAIL

Electrical functionality

1. Optical Switch Voltage Regulation (T6)

• Requirement: The optical switch, whose voltage is regulated by LM 7805, shall not receive more than 5.5 V.
• Test Method:
  • Measure the output voltage from the LM 7805 voltage regulator to the optical switch under both idle and active states.
  • Repeat the test under different load conditions and environmental variations (turning the system on or off).
• Acceptance Criteria: The voltage supplied to the optical switch should not exceed 5.5 V.
• Test Equipment: Digital multimeter or oscilloscope.
• Result: PASS/FAIL

2. LED Driver Circuit Current Limitation (T7)

• Requirement: The current in the LED driver circuit shall not exceed 40 mA.
• Test Method:
  • Power the LED driver circuit and measure the current flowing through the circuit under standard and maximum operating conditions (maximize base current, i.e. i_b = 4 mA).
  • Measure the current in voltage across the 300-ohm source resistor and calculate the current.
• Acceptance Criteria: The current in the LED driver circuit should be ≤ 40 mA in all tested conditions.
• Test Equipment: Digital multimeter
• Result: PASS/FAIL

3. GPIO Input Voltage Limitation to Microcontroller (T8)

• Requirement: The GPIO input to the microcontroller shall not exceed 3.8 V.
• Test Method:
  • Measure the voltage at the GPIO input pin on the microcontroller in both idle and active states.
  • Test under various input signal conditions to ensure stability.
• Acceptance Criteria: The voltage at the GPIO input should not exceed 3.8 V.
• Test Equipment: Digital multimeter or oscilloscope.
• Result: PASS/FAIL

Individual button Functionality:

1. Microcontroller Readings (T9)

• Requirement: On pressing the button, the microcontroller shall detect a logic high.
• Test Method:
  • Monitor the GPIO input pin on the microcontroller while pressing the button.
  • Program the microcontroller to turn on the built-in LED if the button is pressed.
• Acceptance Criteria: The microcontroller should register a logic high signal when the button is pressed.
• Test Equipment: Oscilloscope.
• Result: PASS/FAIL

2. LED Illumination on Button Press (T10)

• Requirement: On pressing the button, the LEDs on the button should light up.
• Test Method:
  • Press the button and visually confirm that the LEDs in the button turn on.
• Acceptance Criteria: The LEDs should illuminate immediately upon pressing the button and remain on while pressed.
• Test Equipment: Visual inspection.
• Result: PASS/FAIL

3. Bluetooth Message Transmission on Button Press (T11)

• Requirement: On pressing the button, the microcontroller should transmit the “ON_buttonNumber” message to the tablet via Bluetooth. The default message from each button to the tablet should be “OFF_buttonNumber.”
• Test Method:
  • Pair the microcontroller with the tablet over Bluetooth.
  • Observe the message log on the tablet’s receiving application or terminal to confirm that pressing the button sends an “ON_buttonNumber” message.
  • Verify that the default “OFF_buttonNumber” message is sent when no buttons are pressed.
• Acceptance Criteria:
  • Upon pressing the button, an “ON_buttonNumber” message is received by the tablet.
  • When no buttons are pressed, the default message “OFF_buttonNumber” is received.
• Test Equipment: Tablet or computer with Bluetooth receiving capability, terminal software for message logging.
• Result: PASS/FAIL

System level integration (involves 5 buttons):

Setup:

• Power the button system (5 buttons and the circuitry) using a 12 V supply
• Place the 5 buttons on a custom mount/footrest that is comfortable to use when a person is in a wheelchair. 

1. Button State Detection and String Composition (T12)

• Requirement: The microcontroller shall detect the state of each button and compose a complete string indicating whether each button is ON or OFF (e.g., “ON_1 OFF_2 OFF_3 OFF_4 ON_5”).
• Test Method:
  • Press each button individually and in combinations, then observe the microcontroller’s generated string by printing the result over a serial port.
  • Confirm that the microcontroller correctly updates the state for each button in the output string.
• Acceptance Criteria: The generated string accurately reflects the current state of each button in the format “ON_1 OFF_2… etc”.
• Test Equipment: USB cable for implementing serial print.
• Result: PASS/FAIL

2. Bluetooth Transmission of Button States (T13)

• Requirement: The microcontroller shall transfer the complete string indicating the state of each button (e.g., “ON_1 OFF_2 OFF_3 OFF_4 ON_5”) to a tablet via Bluetooth.
• Test Method:
  • Connect the tablet to the microcontroller via Bluetooth.
  • Press each button individually and in various combinations, then verify the string received on the tablet matches the current state of each button.
  • Test the system under rapid button presses to confirm accuracy.
• Acceptance Criteria:
  • The tablet consistently receives the correct button state string for every possible combination of button presses.
  • The format matches the specified pattern (e.g., “ON_1 OFF_2 OFF_3 OFF_4 ON_5”).
• Test Equipment: Tablet or computer with Bluetooth receiving capability and logging application.
• Result: PASS/FAIL

3. Stability and Responsiveness Testing (T14)

• Requirement: The system must accurately report button states in real time under rapid button presses.
• Test Method:
  • Rapidly press buttons in various sequences and observe the transmitted string on the tablet.
  • Test responsiveness by pressing multiple buttons simultaneously and check for correct updates.
• Acceptance Criteria: The system should not miss any button press events or provide incorrect button states. 
• Test Equipment: Logging software.
• Result: PASS/FAIL

User Utility Requirements:

1. Kick Button Activation Force (T15)

• Requirement: The kick buttons must be easy to activate, requiring minimal force to be kicked. The experiments have to be done while the person is in a wheelchair.
• Test Method:
  • Ask 5 participants if the kick buttons are easy to kick, given that each of the participants is in a wheelchair.
• Acceptance Criteria: More than 90% of the people should say that kick buttons can be easily activated.
• Test Equipment: None
• Result: PASS/FAIL

2. Power Usage Limitations (T16)

• Requirement: The power usage for the button system should not exceed 12 V or 200 mA.
• Test Method:
  • Connect the button system to a power supply set to a maximum of 12 V.
  • Measure the current draw of the system, (by using a multimeter) under idle conditions and while buttons are being activated.
• Acceptance Criteria:
  • The current draw should not exceed 200 mA under any operating condition, given that the input voltage is 12V
• Test Equipment: Adjustable power supply, digital multimeter.

Result: PASS/FAIL

 

Test Table

Requirement Type

Requirement No.

T1

T2

T3

T4

T5

T6

T7

T8

T9

T10

T11

T12

T13

T14

T15

T16

Mechanical

1

X

Mechanical

2

X

Mechanical

3

X

Mechanical

4

X

Mechanical

5

X

Electrical

6

X

Electrical

7

X

Electrical

8

X

Individual Button

9

X

Individual Button

10

X

Individual Button

11

X

System Integration

12

X

System Integration

13

X

System Integration

14

X

User Utility

15

X

User Utility

16

X

 

Budget

Component	Description	Quantity	Cost per unit	Total Cost
Optical Switch	Omron EESX3173	5	3.57	17.85
Switch Cable	EE-5002	5	5.61	28.05
Voltage Regulator	L7805	5	1.46	7.3
Op-amp	LM 324N	10	0.39	1.95
Micro	Pi Pico W	1	25	25
Protoboard	Prototype Kit	1	9.99	9.99
RGB LED	WP154A4SUREQBFZGC	10	1.91	19.1
Transistor (NPN)	BC 548	10	0.18	1.8
Foot stand	Foot stand (kick button mount)	1	200	200
AND Gate	74LVC1G08GV,	10	0.13	1.3
Sub Total				312.34
Buffer Budget for PCB				100
Cost for custom printing buttons				200
Total				612.34