After the review, I was suggested to the following future directions:
1. The form of the device can be further explored and designed. Right now it might be still too discrete for home setting.
2. The hearing range for different age groups are different. It might be interesting to explore the possibilities of receiving different audio memories for different audiences at home (child, adult, elderly, or even pets!)
Is this a good/useful/informative piece of content to include in the project? Have your say!