What a creative idea! ! !
First of all, the market is not a problem because there is demand. Nowadays, many people write on the whiteboard with a pen, but it just has a taste.
Step 2, you need to examine the cost comparison between your mechanical blackboard eraser and ordinary cotton blackboard eraser.
The third step, and the most important, is to find people who need this concept of blackboard eraser, or in other words, he is more of a person who needs your dust-free concept.
In fact, it all depends on human effort. The key depends on how you promote it.
To say the least, if it cannot become a product, it would be fun to apply for a patent.