Design a calculator for the blind.

A: For this exercise, I am going to ask you to build it as an standalone product. We are targeting for really undeveloped places where internet or phone are not affordable.

I am going to make some assumptions that the blind person using this calculator has brail skills.

There are two sets of users 1) Complete blind and 2) Partially blind, may be able to see the large display.

The general assumption is that the only handicap we are dealing with is blindness. So our focus will be limited to enablement for blindness, and no attempt will be made for other deficiencies.

User needs:

1) Since it is a calculator, it needs to be portable.

2) Should be able to work independently without internet and battery-powered.

3) Large display so partially impaired people can read the display. The input key needs to be equally large.

4) Braille input options.

5) For faster and easier usage, one can talk to it & have read-back capability.

Let me prioritize the requirements for this project. The MVP should have

1) Portability 2) Braille Inputs 3) Large Display and 4) readout 5) No internet requirement.

I am deprioritizing the voice inputs as it is complex & will require internet capability to offload this

FeaturesImpact to userCost to implementTime to buildReasoning

Probability	H	L	L	The person can carry with him
No internet	H	M	M	Given the direction for undeveloped segment, impact to user is high but it will take more time to build some featues and need local processing power
Large Display	H	M	L	Allows for quiet mode and partially blind people
Braille input	H	L	L
Voice input	H	H	H	Without internet, this is a expensive deal, so it is cut out of the MVP
Voice output	H	M	L	Can have headphone for quietness requirement

Solutions :
1) Build the product with a General-purpose CPU for faster time to market.
2) Build a custom ASIC for long-term, low-cost products but high initial investment & a long development cycle.

Option 1) is quick to market & low initial investment but high unit cost.
Option 2) is high initial cost & a long time to build with a low unit cost.

I am considering the pros and cons. I recommend Option 1) as MVP. It helps to weed out bugs and learn the market and user needs. There will be learning of how the power situation will be there and others.

Summarizing my plan:
We are designing a simple calculator for the blind. The consideration for this exercise is limited to blindness only and the operation of the calculator. It assumes someone will help them out with setup.

The product design is optimized for time to market and the low initial cost of development. It offers braille inputs option and two methods of display. Large Screen if one can see and audio readout of the inputs and then the answer.