DIY Portable Pocket Music Player Using ATtiny85 micro-controller(from SD-card)

I made a portable Pocket BOOMbox some days before. It contain a music player and an emergency light system. Here I explain about it. Basically I am a music lover. So I planed to made a music player fully made by me (full circuit). So I search about it. Then I find a website, in which explain a music player work based on the ATtiny85 micro-controller. I plan to make it. I am not more familiar with programming. So I copy the same program which is given in the website. The link is given in the last portion. But I modify the hardware and design a new one with some extra features and the whole circuit is place in a good cover. This is the project over view. Now we going to its details.

Product Details

Finished Pocket BOOMbox

The image in the left side indicate the finished music player. In the frond side there are two speakers and one small push switch to move to the next song and one small SMD preset resistor for controlling the music volume. In the bottom side there is the SD card port, headphone port and a mini USB port for charging the in-built battery(Li-ion cell). In the top white top side there is 3 LEDs Which are used to work as an emergency light system. The music player and the light are controlled by using the SMD slide switch which is placed at the side.

Circuit Details

The full circuit is given below. The micro-controller ATtiny85 is the brain of this circuit. It is an 8pin SMD IC. It read the data from the memory card and it decode it and provide the music as analog signals in its output pin. It generate the analog signal by using the PWM technique. So the output PWM signal is demodulated to the normal audio signal by using a passive RC low pass filter.

Full circuit diagram

Then the filtered audio signal is given to the famous LM386 low voltage amplifier IC. It boost the signal and provide a powerful signal to drive the two small mobile speakers. Connecting the speakers in the right polarity only other wise the destructive interference decrease the volume. The push switch is used to navigate to the next song. The preset is used to control the volume. The capacitors act as decoupling capacitors. It decrease the noise and provide a stable voltage. The LED1 indicating the music player power on status. The LED for emergency is connected to the LED wires in the above diagram. It is protected by using a low value resistor. It limit the current flow. The Li-ion cell charging is done by using a single diode and a resistor. It reduce the charging current by dropping the extra voltage across it. It give a good charging condition for the battery. The Li-ion cell protection circuit is present on the top of the cell itself by the time of manufacturing. the inbuilt speakers are automatically cut off when the headset is connected to the port. It is by usage of the switches in the headset port.

Making

The making process contains two parts first is the PCB making then the cover making. 
The PCB layout is given in the right side.  

These are printed in a photo paper and done the etching by the help of the etching solution FeCl3. The proceed the soldering process. By completing a successful soldering we going to program the ATtiny 85 micro-controller. For this connect wire from the Attiny85 program pins (reset, sck, mosi,miso) and by the use of USBASP programmer board and software AVR burn-O-mat. By this method burn the HEX file and then burn the fuse bits. Then remove the wires and test the circuit by inserting a SD card. Before it copy the music files to it. Ensure that the music files are in the .wav format. 

Completed PCB

For converting the music files I use  NCH 'switch file converter' application. then test it. After completing a successful testing connect all the wires, speakers and battery permanently.

Then make a cover and put the whole circuit into it. For cover I use a small tictac (mints) box. 

The full detailed step by step making process is given in my Instructable page, Please visit it, Link given below,

The necessary files are given in my instrctable page, download from it.

For details about the Program, visit the given link,
http://elm-chan.org/works/sd8p/report.html

For more projects visit my YouTube , Blog, Instructable pages.