Hacking ready made electronic object is one aspect of creation with an arduino. It can be done in many ways to create different effects. One way is to intervene signals within a component and use them to create something different, and another is to change signals within the object and force glitches and other effects.
There are no specific guides or rules for hacking as every electronic item is different. There is a large sense of discovery and adventuring into the unknown, many of the results will only be be clear when the devise is turned on.
There is also a high risk of damaging the object that is been hacked. This is why second hand or cheap objects are often used.
Before starting I had to find some electronic items to hack. I was looking for something with a number of buttons that could be used to interface with processing. After searching through many charity shops the most suitable item appeared to be a calculator from Poundland.
My project had now become a exploration of the object with the intention to subvert an everyday £1 object into something for creating art. "This is not a Calculator" will play with user preconceptions of interfaces and experiences.