+4 votes
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asked in Product Design by (548 points)
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3 Answers

+3 votes

Design a Vending Machine for Blind People
What is the purpose of a Vending Machine – Offer a choice of pre-determined products to someone and help them make a selection and pay for the item.
Clarifying questions –
Is this a physical vending machine for snacks and/or drinks?
Does it accept cash/coins or credit card or both?
Does this vending machine need to work for blind people and normally sighted people or only blind people? – Both?
Do we assume that our blind users are 100% blind (legally blind)?
Lets say that the answers to all these questions is Yes.
What are the main needs for users of vending machines and what are the gaps for blind/visually impaired people?
1. Product Discovery – A vending machine has a stock of different (but limited categories) of snacks and or drinks. People usually “see” these selections to make a choice. People “see” if a product is in stock or out of stock. Gap for blind people – They cannot see the categories and selections visually.
Snacks are usually in the categories of chips, pop corn, bars (chocolate, granola), nuts
Drinks are usually in the categories of water, juice, soda

2. Product Selection – There are usually unique numbers associated with each product selection that a user has to key in or touch to select the product they want. Gap for blind people – They cannot see the number or the location of the product in the vending machine to key in or make a selection for what they want.

3. Complete Transaction – The user is shown the price of the product either up front or once the selection is made. They insert cash, coins or swipe their card to make a payment. Once a product has been selected and paid for, it comes out of the vending machine. The user takes the product out and goes on his/her way. Gap for blind people – They cannot see the price of the product and it may be hard for them to insert the exact cash/coins or swipe their card for payment purposes. It may be hard for them to know where the product came out once the transaction is complete.

Since blind people cannot rely on sight, they will have to rely on their other senses – touch, sound and smell. We can eliminate smell for this use case as the products will be packaged in a vending machine.
We can rely on audio and touch for helping with product discovery, selection and transaction

1. Product Discovery and Selection: Product Discovery and Selection can be done via initiating user input or by reading out a menu that’s not tedious/long to hear. When the blind person comes near the vending machine,

• A very simple way to solve this problem would be to have a visually capable human being sit next to the vending machine and help the blind person make the product selection and choice.
• In the absence of a human being, by facial recognition through cameras, the machine can detect that this person is blind or as a simpler solution – a voice could simply ask if the person needs assistance with selection
• A voice prompt near the machine could ask for – Would you like a snack or a drink today? If the user says – snack- they can be prompted for chips, bars or popcorn. When they say chips- they can be given the 4 different options within the menu and the user can make a choice via voice input. Alternatively, the user could interrupt the voice prompt to specifically ask for a particular product they like and the machine can either confirm or offer a similar product/substitute. Over time, the vending machine could get smarter by learning the user’s preferences.
• Or there could be a mobile solution: There could be integration between an app on the user’s phone and the vending machine for the user to handle these voice interactions through their own mobile phone which would then communicate with the vending machine via blue tooth. Data would be stored about the user’s preferences on the vending machine app on their phone. The phone could also help with detecting the location of the nearest vending machine through voice assisted navigation. The phone/app could even let the user know if the product is out of stock and offer an alternative.
• Once the machine has understood the user’s choice, it can confirm the choice by asking the user and by asking for quantity, amount to be paid.
2. Transaction – Getting the product from the vending machine can be done in multiple ways
a. The selected product could fall in to a mechanical arm attached to the vending machine which would then start buzzing – prompting the user to move their hand towards the arm. Once they place their arm on the mechanical arm, it could guide the user to pick the selected product from there.
b. Payment information should be pre- updated in the mobile app account associated with the vending machine or in the vending machine payment system (similar to Uber or Lyft). A friend or a relative of the blind person could help setting this account up front. The mobile app interaction of selecting the product and confirming the purchase via voice would deduct the payment amount from their account.
c. Another option is to use crowd sourced apps where the blind person can take a picture of the bill/coin they have and ask the mobile app if it’s the correct amount. A company had done this recently using Amazon mechanical turk but I like the first pre-paid option much more.
3. Prioritization
a. Product Selection – I would build the voice activated mobile vending machine app instead of creating the voice processing capability in the vending machine itself . This would make the mobile app more generic and potentially help it work with different kinds of vending machines with different product selections. (I am not going in to data set up requirements here)
b. Transaction – I would build the buzzing mechanical arm to deliver the snack near the blind person so that they don’t have to worry about pulling the snack from a difficult position in the machine.
c. Transaction – I would build the pre-paid account capability to make payment processing easier for the blind person.
This would constitute my MVP.
4. Metrics and Launch Plan
a. Adoption and Engagement– How many blind users are downloading the vending machine app (app downloads), monthly active usage (how many are using the app regularly at vending machines), how many vending machines are converting to this model and integrating with my app (app integrations)
b. Customer feedback – I would get audio NPS feedback from my blind users to see whats working and not working – are they able to select products easily, is the NLP working well?
c. I would first test it in schools or colleges with blind students to see if they adopt and engage with this vending machine – app combination product as well as collect customer feedback. I would continue rolling it out to more schools, colleges, cities across US depending on nature of feedback, adoption and usage improvements.
d. Monetization – I would like to offer these machines at a discount and get revenue from the vendors whose products are being offered in the machine as this is for a socially relevant and inclusive cause.

answered by (135 points)
Hi NapsPM,

Thanks for submitting your answer. I have a couple feedback on this:

– I think you take the right approach of thinking about the customer journey to discover pain points. I would have kept the pain points brief (e.g. user cannot see the location of the vending machine, user doesn’t know if the vending machine supports blind users, user cannot see the menu, user cannot see where the drink comes out from, user cannot see total, user might have difficulty taking out money out of their pocket)

– I think you can describe a bit more clearly how each feature solves a particular problem. For example, for the mobile app idea, I would have said something along the lines of “A mobile app that helps user find blind people supported machines.” or “A mobile app that is connected to the user’s credit card and auto-charges user for their orders from vending machines” The second part of your mobile app idea mentions saving user preferences and informing user if a particular product is out of stock. If you think this is an important benefit, I think you should mention mention its associated problem in the pain points section. Otherwise, you can enter into the listing designing features that don’t solve a problem

– I would have listed a few more ideas to give you more room for prioritization. Couple examples: button in side of the vending machine for blind people to press and start “blind mode”, option to read out Credit Card number loud, Braille digital reading.

– In the prioritization step, I would first list my criteria for comparison (e.g. LOE, revenue, impact to user, risk, etc). Then I would explain how each feature stands against my criteria.

– I think on Metrics, you will want to include a couple metrics that indicate user adoption (e.g. what % of first timers continue using this feature)

I like the idea of starting the test in schools with kids with special needs. It provides a great opportunity to fine tune the product before rolling it out to large number of users.
Loved reading this. It might also be helpful to mention some of the other users in this scenario. We know we’re building for blind people but there are also service technicians, and inventory managers that may need to come restock the machine.
0 votes

1. Is it a physical vending machine?
2. The blind people we target are totally blind, but can hear and speak?
Assuming the answer is YES.

Identify User Groups
Blind people, but also technicals and operators, and for business purpose, we also need to support normal people.
I will focus on blind people since it’s our goal.

Report User Needs
1. When blind people pass by, they need to know where is the vending machine and how to get there
2. When they are in front of the vending machine, they need to know the items on sale, name, price and stock
3. They ‘choose’ a specific item and pay for it
4. Then pick up the item they bought
5. They can leave the feedback

Cut Through Prioritization
I guess 1, 2, 3 user needs are essential, while 4 could be the same as normal ones, since not that much hard to get it, and 5 might be considered in the future.

List Solutions
1. App for the blind people, it will notify them when there is a vending machine nearby, and ask whether they would like to have some snack or drink via voice and vibration
2. The vending machine can detect there is a blind customer there via App, or there is a big physical button for blind people to wake up the vending machine
3. Automatically introduce the items by voice, including name, price and stock, blind people can respond to it
4. Blind people can directly say what they want via voice input, vending machine give them voice feedback
5. Pay by the credit card or app without inputting password (normally no password required under $200)
6. App can be voice controlled in advance with a specific item or the user preference

Evaluate the Trade-offs
1. Impact 5, Cost 4
2. Impact 5, Cost 2
3. Impact 4, Cost 3
4. Impact 5, Cost 3
5. Impact 5, Cost 2
6. Impact 3, Cost 3

I will choose 1, 2, 4, 5 solutions to provide a vending machine with voice and app support for the blind people buy some snack and drinks.

answered by (30 points)
–5 votes


– What type of vending machine? Food/Snack?
– Assuming this is for Google, what is Google’s motivation behind building such a product?

answered by (206 points)

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