The VuPoint PDS-ST410-VP Magic Wand is a portable scanner. Probably how Harry Potter chooses to scan his Hogwarts documents. This device can scan A4 pages with resolutions up to 600 x 600. It will scan a full resolution A4 page in about 28 seconds or a black and white page in less than 4 seconds.
You can also save scanned color or black and white documents on the microSD card. It will cost you $99.99 and it’s compatible with both Mac and Windows platforms.