I build a power supply based on a 7Ah Lead battery and used an Arduino microcontroller and two relays to switch between regular power supply and battery. The Arduino is programmed to detect music flowing through the Dac and than switches to battery power immediately. Between songs the Arduino waits 2 minutes before switching back to regular supply to save battery power. When the battery is almost drained while music is playing it also switches back. To compare the battery powered sound with regular powered sound I added a infrared eye to the setup so I can switch between battery and regular supply from my listening position.
To my big disappointment I don't hear any differences. So for me it was a lot of fun building but not the promissed results.
In front the main power switch, a USB connector to program the Arduino and a LCD display that shows the battery voltage, the dacs' current usage and the psu-switch status (OFF, Music or Charging).
Inside is the 12V battery, a 12V psu, an Arduino powersupply, the Arduino, two relays and a battery charger.
