I'm thinking of improving my Google Glass by DIY building a micro usb to 3.5mm headphone jack with a battery connected to a neck strap out of parts from the internet.
I've already built the neck strap with gorilla clamps and a sewn in pouch at the back to house my 2600mAh USB pocket Power pack Charger External battery pack. It's nice and slim at 95mm x 25mm and round so sits on the back of the neck comfortably.
What I do want help with is the electronics. From what I have researched Google Glass uses a Maxim integrated MAX14532E chip to switch 3 functions, USB, TTY, Audio. In audio mode the pins represent the following.
- Pin 1: +5V
- Pin 2: Right audio out
- Pin 3: Left audio out
- Pin 4: Detect
- Pin 5: GND
Also I've read that a 500kΩ resister will switch audio to stereo and 1mΩ will switch to mono.
Sooo my theory is that if I connect it all up like the following I should have a wearable addon battery pack that should double the battery life and a 3.5mm stereo jack for my beats earphones ?
- Pin 1: + from battery pack
- Pin 2: Right audio out
- Pin 3: Left audio out
- Pin 4: 470kΩ 1/4W 0.25W ±1% metal film resistor (Couldn't find 500kΩ)
- Pin 5: GND (resistor and battery)
Total cost for this if it works is about £35, £70 with some good earphones ! Just I'm in the UK and don't want to brick my glass lol I can't get another pair.