In February 2006 Apple released the iPod Hi-Fi. A portable speaker system consisting of two 80-mm wide-range speakers and one 130mm subwoofer. It can be operated by both power adapter and battery, so that it can be used outside.
To guarantee the top inter-device integration Apple is famous for – the iPods are charged when plugged into the Dock Connector. But when Apple ceased the production of the Hi-Fi in 2007, the charging specification still used 12V (FireWire) - unlike the 5V (USB) specified in 2008. So newer devices like the iPod nano (4. Generation), iPod touch (2. Generation) or the iPhone can not be charged anymore.
But our MacLabor team came up with a solution to fix this issue. All you have to do is to use a step-down-converter to transform FireWires 12V to 5V. To make it at least somehow challenging, you have to tell the iPod or iPhone what type of charger it is connected to. This is done by applying a specified voltage to the USB Data Pins - emulating a charger.
You are going to need the following components:
- Switching regulator,16V DC→5V DC, 1A
- SMDresistors0805: 39k, 2 x51k, 75k
The +12V of the Hi-Fi’s Dock Connector are located at pin 19 and 20 with the ground on pin 15. We have to tap those in order to connect them with the inputs of the switching regulator, which then provides 5V at 1 ampere. Pin 23 (USB Power+) can now be connected to the regulators +5V output, Pin 16 (USB ground) bridged with Pin 15 (Ground).
iPhones determine the current used for charging by defined electric potentials on the USB Data ports. For 1 ampere its 2.8V on pin 25 (USB Data-) and 2.0V on pin 27 (USB Data+).
Thats what the following circuit layout is designed for:
The soldering of the tiny pins of the Dock Connector requires some practice and a microscope is certainly beneficial.
When the pins are connected, all Apple devices will be charged when plugged into the Hi-Fi – even when its powered by battery. This is also true for the brand-new generation that uses the Lightning Connector – although you are going to need a Lightning → 30-pin adapter.
Hopefully we offered an incentive to exhume your old Hi-Fis and bring it to state of the art. If you don’t like to do it yourself, we offer the whole modification for 129€.
So whats up next? We are currently working on a way to integrate an AirPort Express into the iPod Hi-Fi to stream music over AirPlay. So follow us at facebook or twitter for recent updates.
MacLabor GmbH, München, Linus