fbengo:
Thank you so much for your help. I think it won't be easy to let this keyboard communicate with arduino but as you said, the silicone keyboard does certainly have a purpose because in my situation I can´t use a common keyboard because the chance of water damage. It will be better to buy a silicone keyboard made for arduino but I don´t know if they exist??? Do you know a silicone keyboard, which is suitable for arduino?Thank you so much,
Engin
I really don't off the top of my head, I would search the heck out of eBay. With that said, I disagree again that this is a hard job. All keypads like this it work the same. You connect one one side of a set of switches to the Arduino and energize them one at a time, connect the other side as inputs and poll them one at a time. The only issue here is figuring the lines into the output set that has to be switched between high and high impedance and the other input set that has to be polled. And you have all the data in front of you, you just need a continuity tester or alternately a battery, resistor and LED (i.e. make your own continuity tester). Figuring the "pinout" of this keyboard should be a 10 minute exercise.