First of all, my blog
Second of all, the original
Third, files needed
Well, you can read my blog about my rant about proper citation.
Ever since I got started with microcontrollers, I always wanted to know how to build an MP3 player, or just something that could play music. My first electronics projects (and a lot of them) were audio amplifiers, VU meters, etc.
Well, digging around on the web, I found elm-chan's awesome WAVE player that uses an SD card!
External storage is perfect.
Here is a video of it working. It's a comparison of SD audio and regular computer audio.
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Step 1: Parts and Tools Needed
Besides from the soldering iron, PCB, etchant, etc. There are a few specific things you will need...
- SD card (FAT 32)
- Audio plug
- LPF (optional, I was lazy so I didn't)
- ATtiny85 (HEX files is pretty big!)
- Stereo/Mono plug and speakers (in this project I will be using a stereo layout)
- 100nf capacitor (104)
- SMD LED (optional)
- 270 ohm resistor (optional)
- 4.7k resistor
- male and female headers
Now those are parts.
There is a tool I use in order to easily use modified SD cards with my Arduino/ breadboard projects.
In the picture you will see I bought a $5 SD to USB adapter. We will have to modify it a bit to fit our modified SD.
There are two switches that the SD connects when you plug it in. One switch is to indicate whether there is an SD or not, another is to indicate whether you can write to the SD or not. Short both of them to the case/ground
Later in this instructable I will show you how I recharge my Ni-Cd battery.
Step 2: PCB
Nothing more than etching a PCB.
I cut grooves in the side where my SD card socket will be. All PCB files are in the TSJWang's stuff folder. I use Robot Room Copper Connection.
Step 3: Programming It
I did NOT write the code. I am just a curious person writing replicating this project.
If you look in the hex file you will see that the fuses are at the end. If your programmer does not support that, just remove it
Write the fuses AFTER you upload the hex.
I am assuming you all are familiar with AVR programming.
In order to program the SMD chip I plugged in wires to the SD socket. One wire was left, so I just held that one wire down while programming.
It worked fine.
Step 4: Finished!
Now that you programmed it, all you have to do is load some WAV files onto your SD with your modified adapter, and..
How do you recharge the battery?
Simply use an old USB connector and add a 4001/4007 power diode from USB to the battery.
Give it an hour to charge (and no more).
I'm using 400mAh. I probably am overcharging it, but it didn't get hot yet.
Consider your battery and how long you should charge it.
And of course, after it is charged, plug it in (I had an idiot lamp to tell me whether I plugged it in backwards or not), and it should automatically play. press the button to move onto the next file.
And of course, while we are in the mood, this can definitely be implemented into halloween projects. Just add a relay on the button switch or the power supply to play audio files.
For example, an IR sensor that players a spooky sound when someone passes.
Or a part of your costume.
I just use it to listen to music :)
Please note that SD Cards operate at 3.3 v logic. I am using a 4 volt battery (which claims that it is 3.6v)
Please note this, as you may need a logic level shifter.
Thanks, and please upload pictures to show us how you built your WAV player, or to ask any questions.