By default , the TFMINI is outputting Binary format, in order to make it work with Pixhawk as a Lightware emulation you have to change mode to pix.
To change mode, you need to send this string = 42 57 02 00 00 00 04 06
You do a ctrl-c and ctrl-v in the app send box and hit send.
Its now in pix mode and you should confirm by reading from a serial terminal emulator.
Once mode has changed, it is permanent (until you send another command to revert).
Do these steps and you will have a functioning Lidar with pixhawk