Building a Crystal Clear Whiteboard


[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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3D whiteboard without the whiteboard

This one is so simple, and works so well, we’d call it a hoax if April 1st hadn’t already passed us by. But we’re confident that what [William Myers] and [Guo Jie Chin] came up with exists, and we want one of our own. The project is a method of drawing in 3 dimensions using ultrasonic sensors.

They call it 3D Paint, and that’s fitting since the software interface is much like the original MS Paint. It can show you the movements of the stylus in three axes, but it can also assemble an anaglyph — the kind of 3D that uses those red and blue filter glasses — so that the artists can see the 3D rendering as it is being drawn.

The hardware depends on a trio of sensors and a stylus that are all controlled by an ATmega644. That’s it for hardware (to be fair, there are a few trivial amplifier circuits too), making this an incredibly affordable setup. The real work, and the reason the input is so smooth and accurate, comes in the MATLAB code which does the trilateration. If you like to get elbow deep in the math the article linked above has plenty to interest you. If you’re more of a visual learner just skip down after the break for the demo video.

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Robotic whiteboard writes your wall on the wall

[Dave's] drawbot writes his Facebook wall messages on a whiteboard. The setup is pretty simple, depending on a pair of stepper motors and common household goods. As you can see in the image, the stylus is a plain old dry-erase marker held by a big spring clip (the kind that holds a stack of papers together). What you can’t see is that there’s a kick stand to hold the writing head away from the board when moving to the next plot point.

In this example a cursive font is being used, but [Dave] included two other fonts in the code. Those require the felt tip to be frequently lifted from the board, and a servo motor does this by pressing a cotton swab against the surface. This does erase any marker lines it slides past, but it’s a pretty small area that is lost. To control the motors [Dave] is using the EiBotBoard which was originally designed for the EggBot. It’s got a USB mini-b connector which lets a computer push messages scraped from the Internet. Don’t miss the video demonstration embedded after the break.

A small modification would make this into a pretty nifty light painting rig.

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Projector project bears no fruit but it was a fun ride

No matter how good the intentions or how strong your hack-fu may be, sometimes you just can’t cross the finish line with every project. Here’s one that we hate to see go unfinished, but it’s obvious that a ton of work already went into reclaiming these smart white-board projectors and it’s time to cut the losses.

The hardware is a Smartboard Unifi 35″ computer with a projector mounted on a telescoping rod. It was manufactured for use with a touch-sensitive white board which the guys at the Milwaukee Makerspace don’t have. The projector works, but all it will display is a message instructing the user to connect the computer to the white board. Since they’ve got a couple of these projectors, it would be nice to salvage the functionality.

The first attempt was to replace the video signal to the projector. A few test boards were etched to experiment with DVI input. This included several logic sniffing runs to see what the computer is pushing to get the warning message to display. Alas, the group was not able to get the device to respond. But this opens up a great opportunity for you to play Monday morning hacker. Take a look at the data they’ve posted in the link above and let us know how you would’ve done it in the comments.

Wiimote-based whiteboard lets you write on any surface


The Wiimote is a fantastic tool for hackers, given their affordability and how easy they are to work with. [Gareth] had a “eureka” moment while working on another Wiimote-based project, and with some alterations, converted it into an electronic whiteboard.

The whiteboard was built using the IR sensor he extracted from a Wiimote, which is wired to an EasyProp board to process the input. The Wiimote is aimed at a LCD screen, which can be “drawn” upon using a light pen he constructed from an IR led and a few batteries. Any movement of the pen is tracked by the Wiimote’s IR sensor and converted to an XY coordinate, which is then painted on the screen. The sensor has the ability to track up to four points at a time, so you can theoretically use up to four pens simultaneously.

[Gareth] points out that the sensor is not limited to tracking small displays, as the white board can be easily scaled up in size using any kind of rear projection device.

Continue reading to see a video of his whiteboard in action.

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Conways’ wall of life and whiteboard emporium

White board beats chalk board, LED marquee beats white board, and an LED white board trumps them all.

This hybrid lets you draw on the surface with dry erase markers while Conway’s game of life plays out underneath. [Bert] sent us this tip after seeing yesterday’s office marquee. This version is quite similar in appearance but the guts are very different. Inside you’ll find a Parallax SX28 microcontroller doing the heavy lifting. The display is multiplexed but they didn’t go with a common 595 shift register, but a beefier MAX6979 LED driver. We’re not too familiar with this part but it does have a lot of nice features like constant current, and automatic shutdown if serial data stalls for more than 1 second. This is a low-side driver so transistors are used to connect voltage to the rows; the opposite from the setup we looked at yesterday. This was built several years ago and is still working happily even though its permanent home is a breadboard. Source code can be found on this page.

Projector introduces augmented reality to reality

[Raj Sodhi] and [Brett Jones] have been working on interactive augmented reality as part of their research at the University of Illinois. What they have come up with is a stylus-based input system that can use physical objects to create a virtual landscape. Above you can see that an environment was built using white blocks. A camera maps a virtual world that matches the physical design. From there an infrared stylus can be used to manipulate virtual data which is projected on the blocks.

What they’ve created is a very advanced IR Whiteboard. There are buttons on the stylus, one of which opens the menu, made up of circles that you can see above. From there, you can select a tool and make it do your bidding. After the break there’s a video demonstration where a game is set up, using the menu to place tanks and mines on the 3D playing field. We wonder how hard it would be to do this using a projector and a Kinect.

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