add height of projector in readme

README.md

@@ -24,7 +24,7 @@ Here is a quick summary of the project motivations:
 Let's start with hardware requirements before we get too excited about software setup.
 
 * 1x PC with HTC Vive with system specs capable of supporting modern VR experiences.
-* 1x projector mounted about off the ground pointing downward at the floor that makes an approximately 6' (2m) diagonal screen projection. (You can get started without this, but it won't be complete without. [A versatile starter option is the Optoma ML750ST micro-projector with 1/4" tripod mounts](https://www.amazon.com/Optoma-ML750ST-Ultra-Compact-Projector-Enabled/dp/B07GWT1MCC) which allows you to mount it with something like [this arm](https://www.amazon.com/Manfrotto-244-Variable-Friction-Bracket/dp/B000J4FONU) and [this clamp](https://www.amazon.com/Manfrotto-035RL-Super-Clamp-Standard/dp/B0018LQVIA/).)
+* 1x projector mounted about 1.5m off the ground pointing downward at the floor that makes an approximately 6' (2m) diagonal screen projection. (You can get started without this, but it won't be complete without. [A versatile starter option is the Optoma ML750ST micro-projector with 1/4" tripod mounts](https://www.amazon.com/Optoma-ML750ST-Ultra-Compact-Projector-Enabled/dp/B07GWT1MCC) which allows you to mount it with something like [this arm](https://www.amazon.com/Manfrotto-244-Variable-Friction-Bracket/dp/B000J4FONU) and [this clamp](https://www.amazon.com/Manfrotto-035RL-Super-Clamp-Standard/dp/B0018LQVIA/).)
 * 2x computers to feed the projector and scoreboard. Any OS, make or model that has an up-to-date OS and browser and can render medium-complexity WebGL scenes at approx 30 frames per second and connect to the same network as the HTC Vive PC. Most computers made since ~2015 will work for this, I use 2015 era MacBooks with no problem.
 * 2x [HTC Vive Tracker and Receivers](https://www.amazon.com/VIVE-Virtual-Reality-System-Tracker-pc/dp/B0748ZY323/)
 * 2x [Daron brand 1:43 scale NY MTA model bus toy.](https://www.amazon.com/Daron-RT8468-MTA-11-Bus/dp/B00EVQJ5I2)