Not strictly tech, but trying to keep technology simple I thought it would be useful for those people with a Seat, Audi or VW to see how to change their car key fob battery. This will save you the expense of going to your dealership to change the battery when it runs flat (or like mine just refuses to unlock the doors - but lock still works)!
I have tried to cover all the risks involved so by reading this you know exactly what to be careful of and what you're letting yourself in for. This is no different to opening any other small electronic device - if you've done that before you'll be fine. Also, I've heard some VW dealers say that changing the key fob battery yourself may disable the immobiliser feature or reset your key. This is nonsense, my key still works fine and there is no electrical contact between the key part and the fob part - well at least in mine (newer keys or cars that detect key battery level may do).
Disclaimer - I take no responsibility for these instructions, you follow them at your own risk.
Following the order of the image photos (click the image to see it full size).
1) & 2) Flick the key out, wedge a thin screw driver into the key/fob divide crack at the key recess edge i.e. the edge of the nail thin line going all the way across the width (parallel to the buttons) - not the hole or groove inside the recess. With the screwdriver wedged into the edge (it should be perpendicular to the key fob) slightly twist or press the screwdriver to force the small crack open to separate the key part from the fob part. Try both the top - button side - and back side of the keyfob. This requires a fair amount of force to get the small key part lip over large fob's lip (see 2) - be careful.
3) & 4) The non-button side of the fob part has a simple clip on lid, this can be opened from the
non metal ringed end first using your nail. Note that you should not open this like a hinged lid - it is not hinged and could break a small piece of plastic (shaped like a small "u") at the metal end - see in the top right of photo 4. Note be careful to not touch the small IC (chip) when you have the key open - doing this runs the chance of blowing it with a static discharge from your hand (although 9/10 times you should be okay if you accidentally touch it).
The replacement battery is usually a cheap CR2032.
If you want to see a video of opening these keys - by hand without a screwdriver (somebody has done this a lot - I couldn't do it without a screwdriver) have a look at the "switchblade" link on
this VW page
