Project:Festival Radio

ProjectInfoBox Festival Radio
Status:	figuring out which parts to buy
Release Date:	hopefully June 2019
Initiator:	Lukas
Team:	who else would like to help?

I want to turn an old radio into a digital music player for festivals and garden parties.

Originally I wanted to keep the old radio functions in, but will probably scrap that plan to gain more space for batteries and ease of assembly.

If you're good with audio, electronics or Raspberry Pi, I'd apreciate any help!

Major Steps

• remove unneeded hardware
• add batteries & charging electronics
• get basic functionality (e.g. 3.5 mm jack)
• convert the cassette tray into an SD card reader
• (optional) display ID3 information about current song somewhere (old tuner scale?)

Starting Points

• "Make an inexpensive lithium ion battery pack" on Instructables
• patrickweber.info (DE)
• Martin's music box

Shopping List

I got delayed with this project for a bit and wanted to get started quickly, so the sources were selected mainly for speed of delivery, not pricing:

• Raspberry Pi Zero WH
• amplifier board & digital-analog converter: JustBoom Amp Zero pHAT
• power supply considerations:
  • Amp: will work fine with 12 V -> the batteries should be selected accordingly!
  • Pi: 5 V (output included in the HAT)
    • alternatively, it may even be enough to supply power only to the Pi (hack: 12 to 5 V car USB adapter) to save energy & avoid frying the speakers(??)
  • charger: 4S battery pack needs 14.4 V (16.8 V max)
• batteries: 3S or 4S lithium pack(s)
  • 18650 holders from Patrick
  • protection/balancing/charging circuit:
    • small 4S protection/balancing board
    • "wall wart" for 4S battery
• data input: USB/SD/MicroSD to MicroUSB OTG adapter
• optional: Tuner & Aux In
  • would need an ADC to be able to sample the audio signals and output them on the amplifier board
  • alternative: an extra AUX amplifier board and switch inputs (e.g. [1])

Hardware Assembly

• how to set up the Pi & amp
• amp pHAT pinout