A German startup called Lernstift is now launching a revolutionary pen that will alert you if you make a spelling mistake or a grammatical error when handwriting on paper. The pen does not offer the answer to your error, it simply vibrates to alert you that something is wrong and you have to think again.
"Der Lernstift is not at all a cheating pen! After all, it doesn’t give you the correct answer, it merely points your attention to a mistake. It’s like a reliable friend tapping you on the shoulder, saying: "Wait a minute! Something’s not quite right. Think again." Kids will still have to learn orthography and grammar, but that’ll be much faster and much more fun."
The pen can be used in two modes. In calligraphy mode it vibrates if you write illegibly and in orthography mode it vibrates once for a spelling error and twice for a grammar error.
The company is appealing for help to finance further development so if you have some spare cash you might consider investing!
Here's a demonstration film. It's in German but even if you don't understand what's said you get an idea of the product.