EMR
Last updated
Last updated
EMR technology was introduced to drawing tablets by Wacom. And they held all the core key patents to EMR. Those core patents have expired and now other manufacturers can build increasingly sophisticated EMR designs which are begin to rival Wacom products.
Powering the pen - With Passive EMR the pen gets power from proximity to the tablet. However with Active EMR: The pen gets power from a battery inside. More here: Active EMR vs Passive EMR
Position detection - The basics of how the tablet detects position are described here: EMR position detection.
Hover (i.e. proximity detection) -
Pressure detection - See this document for details on EMR pressure detection. It also contains a clarification of pressure detection in the video below (which depicts a very old way of doing pressure detection).
Tilt detection - more here: EMR tilt detection
Barrel rotation detection - very rare in EMR pens
Communication of button press information
Think of the EMR design illustrated in the video as a baseline example that demonstrates the fundamental concepts, different manufacturers can tweak this design in their implementation.
The exact resonant frequency used by the pen will vary.
In the case of the Wacom Bamboo Fun tablet (CTH-661) the frequency is around 750KHz. Source: the last 10 seconds of this scanlime video: https://www.youtube.com/watch?v=oKVCwPn6OPI
We don't know.
We suspect this is MUCH faster than a typical pen report rate of 200Hz.
Even though EMR is used in drawing tablets, there are many other pen technologies in the market, such as AES, Apple Pencil, etc. More here: Digital pen tech
The Apple Pencil does not use EMR. Apple uses a proprietary protocol for their pen. If you are curious about what is inside an Apple pencil, see this video: https://youtube.com/shorts/M9sArtVjRps?feature=share
More here: EMR technical resources