This is a Chord Mojo portable music streamer / player with a Raspberry Pi Zero W. Stream music / radio stations, play local stored files.
Hardware cost 21 usd + microsd card + printing cost ~30 usd :-).
It's a portable version of my Chord Mojo docking station, http://www.thingiverse.com/thing:1716990 .
A universal version with a 18650 battery is here: http://www.thingiverse.com/thing:2267531 .
I use a minimal linux version from RuneAudio (http://www.runeaudio.com/) to stream music from my nas/local storage to the Chord Mojo, using my phone with bubbleupnp/webbroser/rune app to control the dnla renderer/airplay/local media player.
Of course you can use any Linux version that works with the Raspberry Pi Zero W.
Soldering experience for small parts needed, experience with the Raspberry (flash sd card, setting up, config adjustments).
Look at http://www.runeaudio.com/forum/raspberry-pi-zero-support-in-0-4-t3711.html for RuneAudio and Raspberry Pi Zero.
Size: 82mm x 60mm x 11mm
Weight: 55 gr
Boot time: ~30 sec
Runtime streaming: ~6 hours
1 micro usb cable - 2 usd
1 Raspberry Pi Zero W board - 10 usd
1 18650 powerbank - 2 usd
1 polymere lithium ion battery (max size 76mm x 27mm x 8mm) - 6 usd
1 Powerswitch - 1 usd
1 16gb/xx gb fast micro sd card with rune audio image - 8 usd - xx usd
Install the RuneAudio OS on the microsd card and test the installation, use a wall adapter and a mirco usb cable. If everything is fine expand the rune os partition to use the full space of your micro sd card (https://raspberry-hosting.com/en/faq/how-expand-arch-linux-root-partition). Use sftp to the /mnt/MPD/LocalStorage folder to transver your music files.
Print the case, test if the two case parts fits well, some afterwork may be needed (depends of the print quality). If everything fine glue the window in with superglue.
Remove the powerbank board and desolder the big usb connector and the two battery connectors. Solder two cable to the powerbank pcb - place of the big usb connector, pin 1 (positiv - orange cable) and 4 (ground/negativ - white cable) (power out to the Raspberry Pi Zero W), secure them with 2 component glue.
(Read this first and test the placment befor using the glue) - Take the Raspberry Pi Zero W and place it in the down case, should secure fit via the two micro usb ports cut outs. Use a small amount of 2 component glue and put a small ammount on the top of the camera connector. Now you take the powerbank pcb, put some glue on the ferrit part and place it so that it fit the charging micro sub cut of the case, use 2 clothes pegs, wait till the glue is cured. When the placment was right and fits well use hot glue between the Raspberry Pi Zero W and the powerbak board for a secure fit. You can now solder the two cabels to the Raspberry Pi Zero W board (google serach "raspberry pi zero pinout"), using a longer positiv cable and cut them later for connecting the power switch.
Take the Raspberry Pi Zero out and solder the micro usb cable to the underneath of the Raspberry Pi Zero W board, use the golden test points (test the lengt of the cable first). Secure the cabels with 2 component glue.
Solder the powerswitch to the positiv cable.
Solder the battery to the powerbank board and test your work, everything should work now.
Secure the powerswitch in the case with 2 component glue (only underneath). Put the battery, Raspberry Pi Zero W in the case and test if the case can be closed, if it's fine, secure the Raspberry Pi Zero W board with 4 drops hot glue in the case (so you can remove it easy if needed). Secure the micro usb cable with some hot glue. You can secure the battery with adhesive tape but it's not needed (depends on the battery size).
Close the case using superglue.
If you want to use the case for other projects/dacs, don't solder the micro usb cabel to the board, instead open the mirco usb out and/or hdmi port with a rasp, you see the size markin inside the case. Don't open the micro usb power port, you can only use this port if the power switch is off or (better) the battery is secured with a additional diode, DANGER OF FIRE DUE BATTERY OVERLOAD.