I was looking around becouse I need to simulate a OBDII device. I think about to use Arduino for that. I was reading some tutorials how to use bluetooth module but I didn't find any tutorial when Arduino is a server. Alway Android app is a server. Is there way to put SP server in Arduino and Android as a client? And do I need special shield/module for that? If you could gave me some links to tutorials or code would be grate. Interesting for me would be also possibility to send data form computer by USB to Arduino then Arduino push it forward to Android. - but that is not must have, first possibility is more importand for me.
There are two types of bluetooth devices for Arduino. Some are "slave" only and some are both "master or slave".
There is little difference in price so you should buy one that is master or slave.
This page (HC-05) describes one that appears to be commonly used but there are many and I do not have a recommendation. Some devices are in the form of small boards which connect to the pins on the Arduino (normally serial tx/rx) and some are shields that plug onto an Arduino. The article also shows the connection.
By default Android is in bluetooth master mode. This article appears to show the Android programming required to enable a bluetooth slave.