Smart Toilet paper roll

[nickarino]

If I wanted to create a toilet paper roll that had a speaker in it that randomly spoke one of 1000 phrases each time it is turned, I think I would need a particle photon https://www.hackster.io/particle/products/photon that stored the phrases. You agree?

[adafruit_support_mike]

A Particle could do it, but a Teensy or a Feather M0 would also work.

You'll probably need an SD card to hold a thousand clips worth of audio, and a power amplifier to drive the speaker. The PAM8302 is good for small jobs like that:

https://www.adafruit.com/product/2130

Class-D amps work best with analog input, but the Particle, Teensy and Feather M0 all have built-in DACs.

[nickarino]

Thanks so much for the tip on the https://www.adafruit.com/?q=PAM8302%20& . Good stuff.
So if you wanted to build this as cheap as possible what are the parts you would choose? Here is an example: https://www.walmart.com/ip/Hallmark-Spi ... l/54804601

[adafruit_support_mike]

That kind of device has a chip designed for that exact purpose.. a motion sensor, a speaker driver, a big hunk of ROM with encoded audio, and a small amount of logic to make the sounds play.

You can do the same kind of thing with a small microcontroller:

https://learn.adafruit.com/trinket-audi ... r/overview

But data handling becomes more complicated the more audio clips you want to play. The smallest and least complicated storage option would be an SD card, which most microcontrollers can read. The smallest board with everything you need already built in would be the M0 Adalogger:

https://www.adafruit.com/product/2796

You could trim back the board cost with a Pro Trinket:

https://www.adafruit.com/product/2010

And it's possible to wire the pins of an SD card directly to the pins of a 3.3v microcontroller if you're willing to make the card a write-once device.. once you solder wires to its pads, it will be very hard to connect the card to a computer again. The Pro Trinket doesn't have a DAC, but there are external chips you can use, or circuits that can smooth PWM output down well enough to be useful as input to an audio amp.

All the standard design tradeoffs are in play.. size, complexity, cost, and effort.