Design Article
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alinke
Yes that's always the problem isn't it :-) I'll be happy to shoot you a copy of ...
Max the Magnificent
Ah Ha! That clears things up -- thanks for the info. I really have to get back ...
How to build a Magic Mirror (Part 1)
Clive Maxfield
9/7/2010 8:35 PM EDT
Imagine that a guest is about to depart from your house. She (or he) pauses to check her appearance in an antique-looking mirror mounted near the front door. Suddenly, the image of your guest undergoes a Matrix-like 'ripple' and is replaced with a strange face saying…
…actually, we'll move on to consider what the face might say in a moment, but first let me introduce you to a few underlying concepts. Just a few days ago as I pen these words, I came across about a very cool website that describes a really cunning idea called a Magic Mirror (http://diymagicmirror.com).
The idea is that we first mount a flat-screen liquid crystal display (LCD) flush with the wall of our house (cutting into the drywall is the part my wife is not going to be deliriously happy about, but we'll cross that bridge when we come to it [grin]). Next, we acquire a piece of special glass that acts as a two-way mirror. If we place this special glass over a black surface it will appear to be a normal mirror; if there's a light source behind the glass, however, then that light will pass through. So the idea is to take the glass, mount it in an antique picture frame, and hang it on the wall covering our LCD screen.
All we need now is a proximity detector that determines when someone is standing in front of the mirror and a computer that we'll use to drive the display. When someone stands in front of the mirror, we want the proximity detector to send a signal to the computer, which should pause for some short delay (maybe a second or so) and then start to display whatever image, video, or other data we decide to use.
I tell you; as soon as I heard about this my first reaction was to chastise myself soundly for not inventing something like this on my own. My next reaction, of course, was to jump up and down shouting "I want one of these to play with!"
On the one hand, I have to say that the folks at the DIY Magic Mirror site have done a really good job. In addition to a bunch of "How To" videos, for example, they've also created some clever software that can display a variety of animated faces on the screen, including a text-to-speech capability so you can get the "talking head" of your choice to say whatever you wish. This software can also present information culled from the Internet such as stock prices, your local weather forecast, and all sorts of other "stuff". You can download a demo copy of this software for free, or you can purchase a full-up version for around $50, which really isn’t too bad.
From the Magic Mirror site you can also purchase a small hardware "box" into which you can plug a variety of sensors. This box connects to your notepad computer via a USB cable and triggers the software running in the notepad computer to leap into action. However, the cost of the sensor box (without sensors) and the software to run on your computer is $219, which is starting to get a teeny-weeny bit expensive…
On the bright side, we don’t actually need any special software or sensors and suchlike to construct a proof of concept. All we really require is a piece of the special two-way mirror glass, an inexpensive LCD display, and – optionally – a nice antique-looking frame just for effect. In my case, I can start off using my personal notepad computer to display videos and suchlike.
Step 1: Acquiring the special two-way mirror glass
This part was easy-peasy. In the future I might decide to create a bigger unit, but for the moment I'm simply creating a proof of concept, so I followed the advice on the Magic Mirror site and ordered a 12" x 12" sample of this dielectric glass ($19.95 plus shipping and handling) from HiddenTelevison.com.
Although 12" x 12" might not seem very large, it's sufficient to cover a 15" diagonal LCD Monitor with a 4:3 aspect ratio, which is what I'll be playing with at first. A couple of days later a box arrived containing the very carefully packaged glass as shown above.
Step 2: Acquiring an inexpensive LCD display
As you may recall from previous blogs on my hobby projects, I'm easily enthused and tend to leap into action with gusto and abandon. Thus, you have to understand that my starting this project commenced within minutes of my running across the original Magic Mirror site. As soon as I'd placed my online order for the special two-way mirror glass, I headed out to my local technology recycling center, which is located just around the corner from my office (this is fortunate for me since I spend so much time there).
Hurray! I managed to pick up a very nice 15" LCD monitor for only $45 (and there's no tax because they don’t tax recycled technology for some reason).
…actually, we'll move on to consider what the face might say in a moment, but first let me introduce you to a few underlying concepts. Just a few days ago as I pen these words, I came across about a very cool website that describes a really cunning idea called a Magic Mirror (http://diymagicmirror.com).
The idea is that we first mount a flat-screen liquid crystal display (LCD) flush with the wall of our house (cutting into the drywall is the part my wife is not going to be deliriously happy about, but we'll cross that bridge when we come to it [grin]). Next, we acquire a piece of special glass that acts as a two-way mirror. If we place this special glass over a black surface it will appear to be a normal mirror; if there's a light source behind the glass, however, then that light will pass through. So the idea is to take the glass, mount it in an antique picture frame, and hang it on the wall covering our LCD screen.
All we need now is a proximity detector that determines when someone is standing in front of the mirror and a computer that we'll use to drive the display. When someone stands in front of the mirror, we want the proximity detector to send a signal to the computer, which should pause for some short delay (maybe a second or so) and then start to display whatever image, video, or other data we decide to use.
I tell you; as soon as I heard about this my first reaction was to chastise myself soundly for not inventing something like this on my own. My next reaction, of course, was to jump up and down shouting "I want one of these to play with!"
On the one hand, I have to say that the folks at the DIY Magic Mirror site have done a really good job. In addition to a bunch of "How To" videos, for example, they've also created some clever software that can display a variety of animated faces on the screen, including a text-to-speech capability so you can get the "talking head" of your choice to say whatever you wish. This software can also present information culled from the Internet such as stock prices, your local weather forecast, and all sorts of other "stuff". You can download a demo copy of this software for free, or you can purchase a full-up version for around $50, which really isn’t too bad.
From the Magic Mirror site you can also purchase a small hardware "box" into which you can plug a variety of sensors. This box connects to your notepad computer via a USB cable and triggers the software running in the notepad computer to leap into action. However, the cost of the sensor box (without sensors) and the software to run on your computer is $219, which is starting to get a teeny-weeny bit expensive…
On the bright side, we don’t actually need any special software or sensors and suchlike to construct a proof of concept. All we really require is a piece of the special two-way mirror glass, an inexpensive LCD display, and – optionally – a nice antique-looking frame just for effect. In my case, I can start off using my personal notepad computer to display videos and suchlike.
Step 1: Acquiring the special two-way mirror glass
This part was easy-peasy. In the future I might decide to create a bigger unit, but for the moment I'm simply creating a proof of concept, so I followed the advice on the Magic Mirror site and ordered a 12" x 12" sample of this dielectric glass ($19.95 plus shipping and handling) from HiddenTelevison.com.
This looks like normal glass until you hold it up to a dark surface.
Although 12" x 12" might not seem very large, it's sufficient to cover a 15" diagonal LCD Monitor with a 4:3 aspect ratio, which is what I'll be playing with at first. A couple of days later a box arrived containing the very carefully packaged glass as shown above.
Step 2: Acquiring an inexpensive LCD display
As you may recall from previous blogs on my hobby projects, I'm easily enthused and tend to leap into action with gusto and abandon. Thus, you have to understand that my starting this project commenced within minutes of my running across the original Magic Mirror site. As soon as I'd placed my online order for the special two-way mirror glass, I headed out to my local technology recycling center, which is located just around the corner from my office (this is fortunate for me since I spend so much time there).
My LCD monitor seconds before I attacked it with a screwdriver.
Hurray! I managed to pick up a very nice 15" LCD monitor for only $45 (and there's no tax because they don’t tax recycled technology for some reason).
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Max the Magnificent
9/8/2010 3:11 PM EDT
I'm really interested to hear of any application ideas you have for this little beauty...
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alinke
9/17/2010 10:59 AM EDT
cool article, one small correction, the assembled kit from diymagicmirror.com goes for $119
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Duane Benson
9/8/2010 4:49 PM EDT
You could make the 12V definitely not required and simplify the circuit a bit by using one of the common 5 volt PIR motion detectors. Adafruit and a number of other hobby electronics suppliers sell 5 volt detectors for around $10.00. You could probably also change the regulator to a TO-92 form factor to drop the cost a bit and reduce the space requirements. I've used a couple of inexpensive MAX232 type chips with ceramic caps, so that could drop the size and cost a bit more too.
It sounds like a very fun project. I could envision having one of these in the kids' bathroom that shows my face saying "don't forget to brush your teeth."
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Max the Magnificent
9/8/2010 5:15 PM EDT
Hi Duane -- that's a great suggestion -- I'll order one of those PIR motion detectors from Adafruit. The reason Joe put both 12V and 5V regulators on the board was to make my life easier -- but he told me that he's also made the board with a jumper so I can omit the 12V regulator. I'm really looking forward to getting this up and running -- watch this space for Part 2...
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Joe_UK
9/9/2010 2:15 AM EDT
Hey Duane, thanks for the comments. The reason for the component selection was twofold. Firstly, Max tends to come up with these crazy ideas when the shops are closed so I often have to make do with what I’ve got in stock, and second and probably more relevant to a project like this, is component availability around the world and never knowing exactly what constructors will have to hand. For example, those 78 regulators are as common as chips in most places and have the advantage that besides being almost bomb proof and you can bolt them to a heat sink. This is a useful feature if you’re going to be running the unit from a PSU that puts out a highish voltage; perhaps an old Laptop PSU for example; these often put out in excess of 18v. The 12v regulator feeds the 5v one to help keep its operating temperature down but there’s a jumper that can be changed to bypass the need for this regulator if it’s not required. For my own use, a nice switching regulator IC would have been ideal, but they can be difficult for some people to get hold off. The MAX232 chips are also an interesting conundrum. For readers that don’t know, the actual MAX232 is available in several flavours. All need 5 external capacitors to work, but some require 100nf and others 1uf. You can replace the 1uf capacitors with 100nf capacitors if you have a version of the MAX232 that allows it; there’s room on the board, or just leave the 1uf’s installed and they will work with any MAX232 you use.
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hphofstee
9/9/2010 1:24 PM EDT
Toshiba magic mirror with interesting
real-time morphing capablities.
http://www.ps3focus.com/archives/131
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Max the Magnificent
9/17/2010 11:55 AM EDT
Actually I'm a bit confused by this, because the DIY Magic Mirror site provides two links. The one I was talking about for $219 was the Sensor Hub available from MagicMirror.com. The one you are talking about for $119 says Magic Mirror Kit Version (Arduino Equivalent) available from SeeedStudio.com ... I'm not too sure what the difference is.
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alinke
9/21/2010 3:13 AM EDT
Sure, no problem, let me clarify: the $119 version is the assembled board + software (including the Arduino clone) with no sensors. The $219 version is the assembled board in a case with a mounted alcohol sensor for the Breathalyzer feature + software. The $219 is the turn key version meant for non-technical users to get up and running quickly. Hope that helps, thanks.
Al
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Max the Magnificent
9/21/2010 10:53 AM EDT
Ah Ha! That clears things up -- thanks for the info. I really have to get back to this ... there's just so much to do and so little time to do it all in...
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alinke
9/23/2010 1:08 AM EDT
Yes that's always the problem isn't it :-) I'll be happy to shoot you a copy of the software if you want to play around with it, just shoot me a note on diymagicmirror.com/contactus.html
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