Mirror Turns Webcam Into Document Camera

September 17, 2020 by 12 Comments

This is one of those so-simple-I-wish-I-invented-it hacks. Professor [Michael Peshkin] is teaching his engineering students remotely. While he has a nice second camera that he can use to transmit whatever he doodles on paper, most of his students just have the single webcam built into their laptops.

The solution is to put a mirror in front of the laptop cam, and flip the image left-to-right in software. They use Zoom, which has a mirror mode. Done.

The trick is making a nice frame. [Michael] has bent one out of wire, but suggests that a mirror compact works about as well in a pinch. It’s super important that his students can ask him questions backed up by drawings, and this reduces the startup cost to nearly nothing, making it universally useful.

[Prof. Peshkin] is not a stranger to mirror-based pedagogical hacks. Seven years ago, he showed us how to make a transparent whiteboard for video lectures, and it blew up on Hackaday. Since then, there are hundreds or thousands of Lightboards in the wild. We hope this idea catches on as well!

Building A Crystal Clear Whiteboard

November 22, 2013 by 76 Comments

[Michael Peshkin] teaches mechanical engineering at Northwestern University. He likes to use diagrams to illustrate his point, but he also likes to face his students when doing so. His solution was to develop this clear whiteboard which ends up unlocking a lot more than just some hand-drawn schematics.

It’s a bit hard to see what he’s written on the board in the image above but squint and see if you can figure out what’s wrong with this style of teaching? Everything he’s writing is backwards. That’s not actually a problem in this case as [Michael] uses flip teaching. He records and posts all of his lectures online. Classroom time is then used for question and answer on the lecture subjects. In order to get the text to read the correct way he just bounces the camera off of a mirror.

The board itself is a huge sheet of tempered glass attached to the metal frame using bolts through holes in the pane. This leave the edges free. He added extruded rail to the top and bottom to embed strips of LEDs. They light the inside of the glass, and excite the fluorescent dry erase marker ink making it much more visible. [Michael] didn’t stop with the board, he  also rigged up a lighting system that gives him a lot of options, and uses a monitor for dealing with digital overlays. He can put up a diagram on the computer, watching the monitor to see where his marker is making annotations. All this happens in real-time which means no post production! See a demo of these features after the break.

This could all be done without the glass at all, but that would make it quite a bit more difficult for the person doing the writing.

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