Generated Concepts
Problem Decomposition:
- Display Type
- Balance Aids: Arms
- Balance Aids: Feet
- Sensor Types
- Sensor Placement
- Overall Placement
Display Type:
A. LCD
LCD, liquid crystal display, is good option for our display because it uses very small amounts of electric power so it won’t drain the battery.
B. LED
LED, light emitting diode, is usually a small area force often with extra optics added to the chip that shapes its radiation pattern. It is susceptible to failure causing gradual lowering of light output and loss of efficiency.
C. Auditory
An auditory reading would be beneficial to vision impaired users.
Balance Aids: Arms
A. Attached to sensing mechanism
The need for balance aids is a necessity for user’s safety. If the arm rails are attached to the sensors or sensing mechanism the user can hold on to them while being weighed. The balance aides will be adjustable to accustom a variety of users.
B. Attached to the ground.
When the balance aids are attached to the ground it provides a more stable and permanent position for the user. On the other hand, it can not be adjusted and the user will not be able to touch the rails while being weighed.
Balance Aids: Feet
A. Straight Bar
This would incorporate a straight bar foot support coupled to the weight sensor on the toilet. This adjustable support would allow the user to rest their feet while still accurately being weighed. This balance aid could be swung up under the toilet to be out of the way when necessary.
B. Separate Right and Left Foot Aids
This would incorporate two separate foot supports coupled to the weight sensor on the toilet, one for each foot. These could be adjusted separately and would allow the user to rest their feet while still accurately being weighed. These balance aids could be folded or swung out of the way when necessary.
Sensor Types:
A. Strain Gage
Strain gages are a type of resistive sensor that measures the strain of a material. Strain gages are usually incorporated into a Wheatstone bridge. Their strengths include a large linear range, high sensitivity, and a “resting” voltage near zero.
B. FSR
FSRs, force-sensing resistors, have variable resistances that change as a function of pressure. The resistance output is dependent on the area over which the force is applied. FSRs experience hysteresis and are not usually used for accuracy. Hysteresis is a type of history-dependent “nonlinearity” where the output for a given input is a function of the direction of change.
Sensor Placement:
A. Three sensor placement
Three sensors would be placed as shown below. With only three sensors it might not be able to withstand the ultimate weight.
B. Four sensor placement.
Four sensors would be placed as shown below. Four sensors would allow the scale to endure a user of larger weight.
C. Five sensor placement.
Five sensors would be placed as shown below. Five sensors will allow for even a larger amount of weight on the scale.
Overall Placement:
A. Replacement for Toilet Seat
This would involve the weight sensor being designed as a complete and useable replacement for a normal toilet seat. The sensors would be incorporated in between two layers of durable, water-resistant material. The shape would be designed in the general likeness of a toilet seat, with slight alterations in seat width and/or height to make the seat more accessible to all users.
B. Between Toilet Seat and Toilet Rim
This would involve the weight sensor being designed as a thin layer that could be placed between the toilet seat and toilet rim. The sensors would be incorporated in between two layers of durable, water-resistant material. The shape would be a thin, narrow oval ring that could be placed conveniently between the seat and rim. The system would have to be wide and strong enough to support attached balance aids.
Skecthes of Final Generated Concept:
The final concept was generated using the following options:
Display Type: LCD display
Balance Aids: Arms: Arm balance aids that are attached to the sensing mechanism
Balance Aids: Feet: Straight bar foot balance aid attached to the sensing mechanism
Sensor Type and Placement: 5 strain gage sensors placed at intervals around sensing mechanism
Overall Placement: Overall placement between the toilet rim and the toilet seat