EDA DesignLine Blog
What light through yonder window breaks?
Clive Maxfield
2/8/2013 12:48 PM EST
With regard to my recent blog Danger Will Robinson! (Walk towards the light), I've been making some progress on the "prop" to accompany my forthcoming presentation as to how radiation can affect embedded systems at the DESIGN West 2013 Conference and Exhibition.
As a starting point, my inventor friend, Brian LaGrave, who is a master of rooting interesting things out on the Internet, led me to a rather interesting wood-and-leather decorative case from Amazon. This really does look rather tasty from a distance.
The next step was to add some switches and light covers as shown below. I used three antique telephone switches (I'm thinking circa the 1960s, but they could be earlier) that I picked up off eBay some time ago. I also used three antique faceted light covers (from top to bottom we have green, amber, and red) with chrome finishings that my chum Rick Curl sent me a couple of weeks ago on the off-chance that I'd find something useful to do with them.
One thing that surprised me was how long it took me to add these little scamps. The actual process of cutting the holes took only a few minutes – the real time-consuming part was deciding where things should go. One problem is that I've never done any sort of industrial design course (I'll add that to my "wish list"). I do vaguely recollect hearing that odd numbers of items are generally more pleasing to the eye, and also that things look more interesting of they aren’t all centered.
The other side of the coin, of course, is that things don’t look very nice if you just randomly scatter them around. As you can see from the image above, I ended up mounting the switches with 1/2" clearance from the dark wood at the top and 1/2" clearance from the leather strap on the side. In the case of the faceted light covers, I mounted these vertically in the space on the right of the case. Also, for aesthetic reasons, the mid-line of the upper-most light cover is centered on the pivot point of the switches.
All in all I think it's looking rather good so far, but now I've run into a slight problem…
Ideally I would like to use LEDs as light sources, because I can easily control these and generate special effects (like "breathing," where they gradually brighten and then dim again) using a microcontroller. The problem is that I need to use jolly bright LEDs, and these appear as sharp point sources behind the covers.
I tried picking up a small LED flashlight (we call it a torch in England) that has three LEDs and a metal reflector, but that just ended up looking like three point sources. I want something that has the sort of look-and-feel you would get using an old incandescent bulb, but using LEDs.
Next Monday morning on the way into work, I'm going to drop in to a local store called Mock Electronics (sadly they aren’t open at the weekend), because they have all sorts of weird and wonderful electronics equipment hanging around. In the meantime, any ideas you have would be very gratefully received.
If you found this article to be of interest, visit Programmable Logic Designline where – in addition to my Max's Cool Beans blogs – you will find the latest and greatest design, technology, product, and news articles with regard to programmable logic devices of every flavor and size (FPGAs, CPLDs, CSSPs, PSoCs...).
Also, you can obtain a highlights update delivered directly to your inbox by signing up for my weekly newsletter – just Click Here to request this newsletter using the Manage Newsletters tab (if you aren't already a member you'll be asked to register, but it's free and painless so don't let that stop you [grin]).
As a starting point, my inventor friend, Brian LaGrave, who is a master of rooting interesting things out on the Internet, led me to a rather interesting wood-and-leather decorative case from Amazon. This really does look rather tasty from a distance.
The next step was to add some switches and light covers as shown below. I used three antique telephone switches (I'm thinking circa the 1960s, but they could be earlier) that I picked up off eBay some time ago. I also used three antique faceted light covers (from top to bottom we have green, amber, and red) with chrome finishings that my chum Rick Curl sent me a couple of weeks ago on the off-chance that I'd find something useful to do with them.
One thing that surprised me was how long it took me to add these little scamps. The actual process of cutting the holes took only a few minutes – the real time-consuming part was deciding where things should go. One problem is that I've never done any sort of industrial design course (I'll add that to my "wish list"). I do vaguely recollect hearing that odd numbers of items are generally more pleasing to the eye, and also that things look more interesting of they aren’t all centered.
The other side of the coin, of course, is that things don’t look very nice if you just randomly scatter them around. As you can see from the image above, I ended up mounting the switches with 1/2" clearance from the dark wood at the top and 1/2" clearance from the leather strap on the side. In the case of the faceted light covers, I mounted these vertically in the space on the right of the case. Also, for aesthetic reasons, the mid-line of the upper-most light cover is centered on the pivot point of the switches.
All in all I think it's looking rather good so far, but now I've run into a slight problem…
Ideally I would like to use LEDs as light sources, because I can easily control these and generate special effects (like "breathing," where they gradually brighten and then dim again) using a microcontroller. The problem is that I need to use jolly bright LEDs, and these appear as sharp point sources behind the covers.
I tried picking up a small LED flashlight (we call it a torch in England) that has three LEDs and a metal reflector, but that just ended up looking like three point sources. I want something that has the sort of look-and-feel you would get using an old incandescent bulb, but using LEDs.
Next Monday morning on the way into work, I'm going to drop in to a local store called Mock Electronics (sadly they aren’t open at the weekend), because they have all sorts of weird and wonderful electronics equipment hanging around. In the meantime, any ideas you have would be very gratefully received.
If you found this article to be of interest, visit Programmable Logic Designline where – in addition to my Max's Cool Beans blogs – you will find the latest and greatest design, technology, product, and news articles with regard to programmable logic devices of every flavor and size (FPGAs, CPLDs, CSSPs, PSoCs...).
Also, you can obtain a highlights update delivered directly to your inbox by signing up for my weekly newsletter – just Click Here to request this newsletter using the Manage Newsletters tab (if you aren't already a member you'll be asked to register, but it's free and painless so don't let that stop you [grin]).
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elizabethsimon
2/8/2013 1:18 PM EST
I think what you need is a diffuser between the LEDs and the light covers. Maybe some wax paper or something similar would do...
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Max the Magnificent
2/11/2013 4:51 PM EST
Thanks for the suggestion, but I've not had much success with wax paper in the past.
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vvc
2/8/2013 4:39 PM EST
Opal glass would provide excellent diffusion (producing a Lambertian distribution of the light source), but might be difficult to work with in your lamps. You might try a fabric shop for translucent synthetic fabrics, a photo shop for diffusion film, or Amazon (see http://www.amazon.com/Rosco-Roscolux-Diffusion-Diffusing-Material/dp/B000B73OQY) for some material used in theater lighting.
best regards,
george vernon
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Max the Magnificent
2/11/2013 4:52 PM EST
Thansk George -- that material might be the way to go
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Ryan Tennill
2/8/2013 4:56 PM EST
I've heard half a ping-pong ball works well for diffusing LEDs
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Max the Magnificent
2/11/2013 4:53 PM EST
I've tried that in the past for another project -- it didn't work as well as I had hoped/expected
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David Ashton
2/8/2013 7:08 PM EST
HI Max
"...things look more interesting of they aren’t all centered."
In my case, for "interesting" read "Drive me scatty"... I'm a symmetrical kind of guy I'm afraid. But hey, whatever turns you on, baby....
"Ideally I would like to use LEDs as light sources..."
You do realise you can get Led "bulbs" in almost any form factor now - you'd probably be able to get some for whatever fitting your lamps used. Get onto Element14 (new Farnell) and look under Optoelectronics and Displays, then Lamps, then Led Replacement. I just had a fossick on the Australian site and there are heaps, single led, multi led, extra bright, with and without diffusers, etc. Most of them are pretty expensive though. You could make your own diffuser with a disc of greaseproof paper.
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Max the Magnificent
2/11/2013 4:54 PM EST
My first stop will be Mock Electronics on the way into work tomorrow (I didn't make it today)
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Rcurl
2/8/2013 8:18 PM EST
I've got some frosted mylar sheets that should do the trick nicely. I'll drop a couple in the mail to you.
You might also check out LED reflectors and lenses on Digi-Key. Go to Product Index, Optoelectronics, Optics - LEDs - Reflectors.
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Max the Magnificent
2/11/2013 4:56 PM EST
Hi Rick -- that would be wonderful -- also my Chum Alvin suggested sanding the outside of the LED because this would diffuse the light -- and also maybe putting a blog of silver / reflecting paint right on the tip of the LED to block the intense point source...
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David Ashton
2/10/2013 12:33 AM EST
BTW Max
"Ideally I would like to use LEDs as light sources, because I can easily control...."
You can very easily drive an incandescent bulb from a uP port via a transistor. If you use (say) a 12v bulb from a 12V line to a transistor to ground, when the Tr is on it will be at 100% brightness. You can pulse width modulate the Tr to dim it - it won't be as linear as a LED but it would be quite acceptable.
Just a comment - couldn't you find an old meter (preferably a round face type) to complement your switches and lights? I guess it would not be as visible to an audience though...
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Wnderer
2/11/2013 1:43 PM EST
Looks like he went for Star Trek OS retro with switches, buttons and lights. The three switches in a row remind me of the transporter room controls. Dials and knobs are more Buck Rogers/ Flash Gordon.
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Max the Magnificent
2/11/2013 4:59 PM EST
I don't know why, but I'd simply never thought of using PWM to control an incandescent bulb -- I was thinking that the bulb wouldn't be fast enough to respond, but at the end of the day a PWM ration of 1:1 (for example) equates to 50% of the power...
I thought of adding an old meter (I have a bunch here in the office) but you couldn't see it in a large room -- which is also why I decided to leave out the geared clock -- but I think it will look great just the way it is (once I've got the lights working :-)
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David Ashton
2/11/2013 6:05 PM EST
Lamps (because of their coiled filaments) are a bit inductive, so if you PWM them at a very high frequency you just might get strange things happening. But anything in the KHz region shouldn't worry them. They are after all usually fed with 50/60 Hz...anything above that you shouldn't get any flicker.
I once used an auto bulb as an RF dummy load. At 40 MHZ it was quite good, but at 80 MHz it needed a trimmer cap across it to null out the inductance. Cheaper than buying s proper load.
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ndancer01
2/11/2013 5:23 PM EST
The ultimate machine, of course, is something about the size and shape of a cigar box with one switch on the front. When you throw the switch, there's an angry buzzing inside, and a few seconds later, this mannequin hand 'ratchets' out, and turns off the switch. Then the hand pops back inside, the lid closes, and the buzzing stops.
This is the ultimate machine--almost human. The only thing it does, is turn itself off.
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Max the Magnificent
2/11/2013 6:10 PM EST
I think it's called a "Useless Machine" ... I have one sitting here on my desk
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ndancer01
2/11/2013 5:25 PM EST
I believe it was invented by Claude Shannon
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ndancer01
2/11/2013 5:30 PM EST
When I was at Boeing, there was a rumor going around that there was a box for the uninitiated. It was welded metal and had one button--and a sign that said, "Do not press this button."
It generally sat there for less than half an hour before somebody pressed it. Contents? A battery, a latching relay, and a klaxon. In that metal box, it was loud. I was told that more than one went into the Duwamish River (which ran close to the plant).
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Max the Magnificent
2/11/2013 6:11 PM EST
LOL
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E-Unit
2/13/2013 3:38 AM EST
Your switches look like "Kellog Keys", they were standard telephone switches here in the UK until the "Ericcson Keys" came along. The BBC (Our national radio) had an AEI (I think!) built control room from the early 60's which htey ripped out in the 90's. It had hundreds of these, some of which were never even used. I think they were replaced by the flimsier Ericcsons shortly after.
For Lamps, you can drive bulbs or LEDs from the old ULN200* family ("ULN2003" suits TTL) which will take PWM etc. And yes, bulbs will integrate the pulses mech better than LED's, especially for migraine sufferers!
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David Ashton
2/13/2013 3:52 AM EST
The nice thing about these keys was that you could get 6, 8 or even more sets of contacts on a key. The most you can easily get with today's toggle switches is 4.
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Max the Magnificent
2/13/2013 12:43 PM EST
You are correct -- mine each have a bunch of contacts -- some of them are "switch to make" and others are "switch to break" -- plus one of the switches works as a momentary switch if you press it down (when you release it it returns to the center position) and toggle if you switch it up.
They are very, VERY tasty!
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Greg.Brent
4/8/2013 10:25 AM EDT
My p&p uses polyethylene for an LED diffuser on its vision system.
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