Is there a sensor to measure a distance between 2 point as in range [0-2 meter]?
You can use a lot of different methods with advantages/disadvantages:


Use an IR LED/receiver and calculate the distance of travelling of the lights. Disadvantage: you need a very precise timing mechanism (light is fast), also take latency into account for non-light parts, and hardware needs to be in visible range and pointing to each other with LEDs)
Use an ultrasonic sensor like SR-HC04. Disadvantage: devices must point to each other in a small precise angle.
Using an RF method and sending/receiving e.g. via nRF24L01+ 2.4 GHz trasnceivers, to check the difference in time between sending and receiving when very close or a few meters apart. However, there might be aspects that might distort the result (other receivers/transmitters, what kind of material is in between, nRF antenna placement/direction etc). Using lowest speed (most reliable), highest power.