To use the Bolt with the Raspberry PI, all you have to do is connect the UART tx and rx pins of the Pi to the rx and tx pins of the Bolt. (Remember to use a common ground connection)
On the software side, you can use modify the serial port code of WiringPi, to send and receive data from the Bolt.
On the cloud side, you will need to use the Bolt UART API, the link is given below
We do have an Arduino library, so if you can interface your sensor to an Arduino, you will be able to easily connect it to the Cloud using the Bolt.