Keypad playing sounds - Recommendation for design

Hello everyone!
This is my first message in this forum and I really appreciate your help.

I want to design a gadget for my uncle who can not speak, just move her fingers. As I don't have an electronic profile (i am software developer), I am asking you for assistance in order to design the best cost-effective solution for this idea

Functionality: A keypad (colorful) that can play sounds associated with their own keys.

Idea-components:
*Speaker - Q1. As the gadget probably will go on a wheelchair, it should be a rectangle (not too high). Where can I find it? Q2. What are the main characteristics of a speaker? What potency? Vats?. It has to be enough strong to let her communicate in the street. I do not know how to measure it.
*Mp3 player - Q3. Is it required? or maybe it has to be integrated with the PCB/microprocessor?
*Microproccesor/PCB - Q4. I know abut raspberry, elegoo and Arduino. However, I think these are overpowered for the simple functionallity to receive an order from the keyboard and play a sound. Maybe they consume more energy? What is your recommendation for this component?
*Keyboard - Q5 It has to be something like a matrix keypad but with color in the keys. I have not found anything on aliexpress related to a full matrix 3x3 or 4x4 with colors. I have found only normal keyboards with numbers. Maybe buy the keys separately and with their custom color?
*Battery. A thin battery. Q6. Will you design using standard batteries or use external battery than can be recharged with energy/power. Q7. What power is required for this design taking into account the gadget should be located on the arm of the wheelchair (it can not be so big).
*Case. Q8. Would you buy a standard box case and after receive it make some customization to place the keyboard and the battery connection charger? Q9. If it is a custom case, where will you get it? I will design it using SketchUp or some software in order to send it someplace.

Additional questions:
Q10. Is it my design correctly? Or will you recommend something else? A new better design idea?
Q11. Any cheap place to buy those components if I have to buy it for more people (to make between 30-50 gadgets for the nursing home)?
Q12. What is the cost per component you estimated?

Thank you a lot! Feel free to ask whatever you want.

Where is the schematic which this design refers to?

Btw, welcome to ETO!

Great project. There are a lot of different ways to approach this and, as you refine what you want to do, you can search out all of the examples that have been done before and that is probably a good way to start to refine the project specifications.

At this point, I don’t think that you have a design – do you? You do seem to have a good idea of the components that you want to use. Those seem reasonable to me, but again, there are different approaches.

Take a look at this example, which uses an inexpensive Arduino and **broken link removed**. Even though you don’t want to design that particular board, it basically shows all of the components and the code for the functionality you do want. Some will be definite considerations for your project (like the DFPlayer) and some less so (like the custom manufactured case).


You are a software developer with specialties in Analog IC Design, FPGA Design – maybe you have the skills to avoid the controllers in the example and come up with a cheaper way? Do you want one for your Uncle or 30-50 for the entire nursing home? That might also have some bearing on how you approach the project. Do you have a budget?

DrG said:

Great project. There are a lot of different ways to approach this and, as you refine what you want to do, you can search out all of the examples that have been done before and that is probably a good way to start to refine the project specifications.

At this point, I don’t think that you have a design – do you? You do seem to have a good idea of the components that you want to use. Those seem reasonable to me, but again, there are different approaches.

Take a look at this example, which uses an inexpensive Arduino and **broken link removed**. Even though you don’t want to design that particular board, it basically shows all of the components and the code for the functionality you do want. Some will be definite considerations for your project (like the DFPlayer) and some less so (like the custom manufactured case).


You are a software developer with specialties in Analog IC Design, FPGA Design – maybe you have the skills to avoid the controllers in the example and come up with a cheaper way? Do you want one for your Uncle or 30-50 for the entire nursing home? That might also have some bearing on how you approach the project. Do you have a budget?

Click to expand...

Hi, thanks for the reply! I have the idea but I am looking for a better design than mine (I could say now Arduino R3 + DFPPlayer + LoudSpeaker +keypad matrix 3x3). As I posted, I have lots of doubts... like what the speaker should I use? (keeping the gadget not too high...like a rectangle block in horizontal or just 2 small with holes in the case).

lauracastellana said:

Hi, thanks for the reply! I have the idea but I am looking for a better design than mine (I could say now Arduino R3 + DFPPlayer + LoudSpeaker +keypad matrix 3x3). As I posted, I have lots of doubts... like what the speaker should I use? (keeping the gadget not too high...like a rectangle block in horizontal or just 2 small with holes in the case).

Click to expand...

The DFPplayer seems like a reasonable choice (<US$2). There are tons of project examples in that regard. You probably could do with a smaller Arduino clone than a UNO. But you did not answer these questions:

DrG said:

Do you want one for your Uncle or 30-50 for the entire nursing home? That might also have some bearing on how you approach the project. Do you have a budget?

Click to expand...