Speedometer

So I'll be using Arduino uno, obd2 pin and a Bluetooth receiver(HC05). I want to take the speed data from the obd2 pin to the arduino. As the pin can be connected through bluetooth, I shall require a bluetooth receiver as well.

Here is the project which calculates the rpm of the car.

https://forum.arduino.cc/index.php?topic=149453.0

I don't need to display the speed. I just need to give output 1(or 0) from the arduino if the car is under a speed limit, otherwise the reverse.

Any idea for taking out the speed?