The concept of having a digital gaming table got stuck in [RobotGuy’s] mind over the weekend and he managed to whip this up in no time using materials on hand. He already had a ceiling-mounted projector which just happens to reside immediately above the space occupied by his coffee table. By swapping that piece of furniture out for a white Ikea table, and adding a mirror to the projector he now has the virtual gaming surface he was looking for. The mirror mount is nothing more than a desk lamp that includes a spring clamp and flexible neck. He hot glued the piece of mirror to this, and attached it to the projector’s ceiling anchor. Since rear-projection screens are common, all digital projectors have the ability to mirror and rotate the image being displayed so that it appears on the table in the correct orientation.
We love the look, but this is really only one portion of a digital gaming project. We think the table needs some interactivity. We often see this done using infrared light processed by a webcam. That multi-touch option is not going to work with a standard table since the camera needs to be on the opposite side of a translucent surface. But if you don’t mind using a stylus this IR whiteboard technique would work.
This mirror has a large monitor behind it which can be operated using hand gestures. It’s the result of a team effort from [Daniel Burnham], [Anuj Patel], and [Sam Bell] to build a web-enabled mirror for their ECE 4180 class at the Georgia Institute of Technology.
So far they’ve implemented four widget for the system. You can see the icons which activate each in the column to the right of the mirror. From top to bottom they are Calendar, News, Traffic, and Weather. The video after the break shows the gestures used to control the display. First select the widget by holding your hand over the appropriate icon. Next, bring that widget to the main display area by swiping from right to left along the top of the mirror.
Hardware details are shared more freely in their presentation slides (PDF). A sonar distance sensor activated the device when a user is close enough to the screen. Seven IR reflectance sensors detect a hand placed in front of them. We like this input method, as it keep the ‘display’ area finger-print free. But we wonder if the IR sensors could be placed behind the glass instead of beside it?
Continue reading “Cloud Mirror adds Internet to your morning ritual”
In a project that only spanned about three weeks [Lars] built this laser light show projector using parts scavenged from his junk bin. We’ve seen the concept many times before, all you need is a laser source and two mirrors mounted on a spinning bases. The laser diode for this project was pulled from a recordable DVD player. That beam passes through the optics from a laser printer to give it the focus necessary to get a good projected image.
[Lars] played around with the mirror angles until he achieved just the right look. The first mirror is mounted about 4 degrees from being flat with its motorized base; the second is off by about 6 degrees. This introduces slight oscillation in the beam direction when the motors are spinning. By adjusting the speed of each motor you get different patterns. Adjustments are happening completely at random thanks to the BasicStamp2 microcontroller which hadn’t been used in years. Fifteen lines of code were all it took.
Want a laser that’s not controlled at random? Check out this addressable galvanometer-based show.
[Ben Krasnow] is working on a project that uses an extremely expensive specialty mirror. He needed to cut curves into it, taking care not to chip or shatter the material. He’s found a reliable way of doing this with a CNC mill and is sharing his methods.
The material he’s working with is a cold mirror; it reflects visible light while allowing infrared light to pass through. He had to custom order it, breakage is not acceptable. [Ben] explains that the biggest risk when milling glass is the clamping method used. He built his own jig and uses shims, rather than clamps, to secure the material along the X and Y axes. It is held down on the Z axis using a bar of acrylic spanning from one side to the other with rubber feet on the bottom.
A diamond burr cutter does the work, spinning at 3000 RPM. [Ben] recommends moving the head at the slowest rate possible in order to give the cutter time to do its work. And of course the material needs to be kept cool by pumping cutting fluid across it. As he shows in the video after the break, what you get is a piece of glass that comes out with clean and smooth edges.
In case we’ve sparked your curiosity, this mirror will be used during an MRI scan. The patient looks at a monitor reflected in the mirror at a 45 degree angle. At the same time, an infrared camera records the patient from the other side of the mirror to monitor where they are looking.
Continue reading “Milling curves into mirrors and glass”
The image you see above is the result of a simple analog projection clock. It shows the time on the ceiling. We have one in our bedroom but it’s a red digital display which we don’t think is nearly as fun as this clever hack. Grab a cheap analog clock, a mirror, and a white LED and you can build your own.
The mirror is going to reflect light from the LED onto a ceiling or other surface. It acts as the clock face. The tick marks for each hour were made by scratching the reflective material (often called the silvering) from the back of the mirror. A hole is drilled at the center of the class and the analog clock is mounted with its hands on the business side. The one problem with this setup is that since the light is being reflected, the clock will appear to run backwards. Not a problem, if you just reverse the polarity of the coil which moves the clockwork the projection will move in the expected clockwise direction.
[Gordon] sent us a tip about this simple laser trip wire system after reading yesterday’s post on a more complicated laser security unit. That build did a lot to provide functionality, such as a system to disarm the trip wire, and a robust light detection circuit. This time around there’s more happening with smoke and mirrors than with electronics.
[The Timmy] built this simpler version based on a laser trip system from Afrotechmods (video of that one is embedded after the break). He had a bag full of small square mirrors which he attached to a wall with some poster putty. A laser module shines a beam of light onto a cadmium sulfide sensor after it bounces around the optical network for a while. That CdS sensor controls an N-channel MOSFET, switching it off when light is detected and on when the intensity of the laser is absent. This example just turns an LED on and off, but since it uses logic-level voltages you can choose to add a microcontroller to the mix if you have other plans in mind.
Continue reading “Laser trip wire – the bare essentials”
By and large, the standard household mirror is one item that has not made much real progress over the years. They hang on the wall reflecting light, and that’s about it.
A few years back, some students studying in the Department of Interaction Design at Chalmers University sought to enhance their morning routine with an interactive mirror. Their project was constructed using a two-way mirror with several Arduino-driven LED displays embedded behind the glass. Once a hand is swiped past the pair of embedded light dependent resistors, the display is activated. Subsequent hand swipes trigger the mirror to toggle between the different modes, providing the user with the current time, weather information as well as a toothbrush timer.
The project writeup is quite thorough, including plenty of source code and information on some of the components they used. You can take a look at their work here (PDF).
Check out the interactive mirror we featured that served as inspiration for their project.
Continue reading “Bathroom mirror HUD displays time and weather”