This video explains how it works:
Step 1: Parts and tools you need
A microcontroller (I use a Picaxe 18x)
A few resistors might come in handy
Solder, cutters, tape etc.
Oh, and another working cellphone.
Step 2: Making it
My setup uses four outputs (four different keys on the phone) and one input on the microcontroller. It allows me to send a SMS text message (or call) to my hacked phone and it then cycles through the code, clicking its way through the menus, taking photos and returning them to me.
I was optimistic about the joystick and quickly soldered up the wires. The joystick has up, down, left, right and center as possible connections. I had to crack open another joystick to figure out the connections. "Making a "right" or "left" requires many different pins to be connected in a certain manner and order, e.g;
First; yellow + black + blue + brown
then; purple + orange
I experimented and found that I could rationalize by always keeping some wires connected. This worked but made the joystick on the phone immobilized. For "Right" I ended up using two relays:
on relay 2
on relay 1
off relay 1
off relay 2
Relay no.1 is the top left button on the key pad ("Select" and "capture"). Relay no.3 is the top right button on the key pad ( "more" and "send").