yPod

Description

Times of the mobile media players are gone. Now everyone is simply using their smartphone to stream digital music from some on-line service. Maybe it isn't a distant past, but looking back at those devices I have this feeling, like it was co completely different era (Well... Maybe it was...) and I am really nostalgic about portable multimedia devices I used fifteen years back.
So... Some time ago I asked myself a question: given recent developments in electronics and all the tools/parts that are now accessible for an amateur, will I be able to build something reminiscent of 2005 iPod? I decided to simply try. ;)

Details

When finished, device will be fully functional mobile music player, inspired by the media players from first decade of XXI century, mainly an iPod. As you probably already figured it out, name of the project is a pun - you read "yPod" like "why pod" and the answer is obvious - "Because i can [build it]. ;)

Device is mounted on two layered, homemade PCB, made with a laser printer and thermal transfer method. Yes, I know there are companies that will produce small number of professional looking boards for a very small price, but I simply didn't want to wait for a package arriving from China. Anyway, this is probably one the last that complicated boards, that I ever etch by myself...

The "heart" of the device is the STM32F407 chip, which is powerful enough to handle all the heavy tasks like decoding audio streams and generating graphics, so I decided to not include hardware MP3 decoder in this project, opting for a I2S audio codec (WM8731).

Player is designed to support up to three media storage devices:

SD card connected to SPI bus (it will serve as an internal storage)
SD card connected to SDIO bus (external, removable media)
External USB storage.

The interface will be shown on 240x320 LCD screen. There is a possibility od adding touch screen later on, but main function will be controlled with buttons and rotary dial.

Of course device is powered by the battery charged with micro USB charger. To preserve power I decided not to use linear regulators. Required voltages of 3.3V and 5V (for USB) re being produced by the switching converters.

At this point hardware is nearly complete and tested. I just need to order one part to finish building USB power circuit. Then writing the software will be the only thing to do.

Components

1 × STM32F407 Microprocessors, Microcontrollers, DSPs / Microcontrollers (MCUs)

1 × WM8731 Audio ICs / Audio CODECs

1 × USBLC6 ESD and TVS Suppressors / ESD and Transient Voltage Suppression (TVS) Diodes and Arrays

1 × MCP73831 Power Management ICs / Power Supply Support

1 × TPS2500 Power Management ICs / Switching Regulators and Controllers

Project Logs

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New board from PCBWay

Marek Więcek • 05/02/2022 at 14:55 • 0 comments

It was a while since I posted an update on this project. It changed recently, when PCBWay company contacted me offering free set of PCBs for the yPod. It was an impulse I needed to move things a little bit forward with this project. My original design had some issues that required factory manufactured PCB to fix. For example due to differences in trances length I wasn't able to operate 4bit SDIO interface at full speed. Equalizing those traces required putting vias under microcontroller which is not easy (or nearly impossible) with homemade printed circuit boards. With boards from PCBWay it was an easy fix.

I also used that opportunity to slightly reduce size of the board and add FM radio module, connected to the input of DAC chip.

I uploaded gerber files and less than week later package arrived. PCB quality is great.

I was able to populate one of this board with most of elements. Unfortunately I wasn't able to get some of them due to current situation on semiconductor market. The most obvious solution would be to simply disassemble them from working prototype, but I really do not want to do this. Working device would be valuable as a reference while working with the next iteration. Moreover - PCB for yPod prototype is one of the best homemade PCBs I ever made. I do not want to destroy it by giving it thermal shock during hot air desoldering. And of course I'd like to photograph two completed boards together. :)

I will rather try to buy missing parts somwhere.