Hi! I'm new here (and to Arduino) and I'd like to make a musical greeting card that plays a custom song when opened. I'm aware that this is not an original idea, but I didn't find any builds when searching.
Can anyone point me to some parts to get started, and/or a guide to what components I would need?
I picked up a dfrobot beetle to tinker with and got it to receive inputs and send outputs. I'm familiarizing myself with the programming language. This seems like a very simple project, once I know what parts to get.
I figure I need:
an arduino capable of playing audio and storing an audio file (maybe this?)
a slim speaker (this?)
a slim microswitch that the paper card can hold in the closed position until it is opened
a coin battery that can keep the arduino powered long enough to do its job
perhaps a battery holder
If all of this has been addressed and I'm retreading old territory, I'd be happy to know of someone else's solution. Thanks for reading!
To achieve very low current so the the battery will last, you will probably have to put the processor in your project to sleep and design the system to use very little current. Pretty challenging.
As to an audio recording chip if you wish to roll your own then there are plenty of chipcorder modules out there to work with. There is no need for an Arduino or any uC (micro-controller). These chips can be powered by a simple set of contacts and a coin cell battery. The contacts have for example a sliver of non conductive material between them which is pulled out when the card is opened.
The first and original chip corder integrated circuits were originally developed by ISD and the design was bought by Nuvoton. The early chips were limited to about 20 seconds recording time. Today Nuvoton offers a wide varity to work from. Again I see no need for a uC. Not for your planned project anyway.
A Google of ChipCorder should get you a few dozen hits.
Thanks for the suggestions. Would the DF Player Mini require another board to function, or is it standalone? The description suggested that it needed a separate microcontroller.
Great idea about the light-dependent resistor, very small.
I looked into sleep mode and waking the board using an interrupt. I wasn't successful with my Beetle board, but that is probably a me problem.
I appreciate your feedback. Here's a little more about my project and why I think it requires a bit extra.
I'd like this device to play a song of my choosing on a loop until the battery dies or it is destroyed. I'd also like to embed lyrics in the form of commented code in the event the recipient is clever enough to download the code from the controller. I'd also like the experience of building this project using arduino, as I've been looking to get into it for many years, and I sort of "need" a reason. This project is a good reason, to me at least.
In post #3 I linked to the DF Robot page on the mini. It looks like you can add a few buttons and a speaker (and power) and use it without a microcontroller.
The DFPlayer Mini MP3 Player For Arduino is a small and low cost MP3 module with an simplified output directly to the speaker. The module can be used as a stand alone module with attached battery, speaker and push buttons or used in combination with microcontrollers such as Arduino, ESP32, Raspberry Pi and any microcontrollers with Uart
Yes, it can be run stand alone or control it with a uC.
I doubt it will be an easy fit into a greeting card though. If you take apart a greeting card which uses a pre recorded audio you will fiind what looks to be a black blob which is a custom made chip like I covered in post #5, commonly called a chipcorder. Anyway a DFPlayer will run fine standalone. You just add buttons.
Even if you do, they're not readable in compiled code. What goes into the microcontroller looks nothing like what you wrote on the screen. It all gets turned into hex code. If you want to include a puzzle think elsewhere.
That's also good to know. There probably isn't a way to make that Hex code representative of text characters or anything useful either. That's too bad (for my original plan).
Someone who really really knew what they were doing and had lots of extra time on their hands and a large enough incentive could go and find the text if they already knew it was there. It would be the worlds most grueling word search puzzle though. Definitely not something one could stumble upon.