Instructables
Picture of Analog LED Table
This is my instructable on building a simple LED table that works and responds in an analog manner. It was to be built of individual pods with 4 LED's with there own photo-transistor to detect movement, or rather a disturbance in the light/wave patterns above them. It seemed simple at first, hook up a couple LED's & a resistor to a power source that is interrupted by a photo-transistor to act as a switch and voila, right? place foot in mouth here.

Please rate me, it just takes a click.  Thanks!

Weeks later of googling, and reading forum after forum I came up with a circuit that I was happy with. Realistically this would have been easier using a micro controller but I was rich on time "or so i thought" and low on cash. Total cost of this panel including the wood frame has been around 35$ Now of course I did have to scrounge, look for freebies and of course use eBay. I live in a quite remote section of Northern British Columbia, so sadly there was no quick run to an electronics supply store. This table was to go to my best friend for a Christmas present but sadly, I ran out of time. He got an radiant ceiling mounted heater for his garage instead. So the LED pods I built, sat in bin being bounced around for a year and a half. They looked so sad and neglected, all they need was a home, some 12V juice and a little love, See what they needed for a happy home on the
next pages

ADDITION:
  1. I forgot to mention, this table was built as a panel. That is why the power is on the side. The panel can easily be moved about, it can be placed on my coffee table, kitchen table or even the wall as interactive wall art. I believe this is important as my family likes to be able to mix up our furniture arrangement and may not always want such as large piece to be hard to move around . In pictures and videos the table is sitting on top of my living room coffee table. It would be simple to add permanent legs or even cheat a little and pick up a cheap used table and buck the legs to the desired height
  2. I have added a new circuit diagram in step 4, feel free to comment, give advice and poke holes - its how we all learn, and I have a lot of learning to do!
  3. Added the write-up on building the frame, guess I didn't save it properly when I wrote it the first time.  Live and learn...
  4. See step 11 for some pictures with a paper diffuser added!  This optional but it does soften the look.  This is fire resistant paper, the kind used for lamp shades, I thought this prudent as the power source could potentially spark or heat up
  5. Wife's friend they sell similar tables to parents with children with sensory seeking Autism.

Before building this table, remember your are using dangerous power tools, exposing yourself to potentially lethal doses of electricity, cutting yourself with broken glass, burning yourself with solder, dealing with nasty paint fumes and in general annoying the crap out of those you live with, and danger unto its own! So be warned!
 

 
 
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pepehdez3 years ago
Last post was almost a year ago, but I just stumbled upon this project and I really like it, I hope my 2 cents get to you on time, how do you feel about adding a fadeout effect to the LEDs ? I think it would make it look even better, and is fairly easy to do, you just need to add a capacitor to the circuit.
FadeOut.jpg
iminthebathroom (author)  pepehdez3 years ago
NICE, i am going to make this the featured comment so others can learn from it, including me! Awesome
iminthebathroom (author)  pepehdez3 years ago
exactly, I hope the last 3 commentors at the top look for this!
krzysztof212 years ago
Welcome to the attached diagram fotce is where you should slowly dim lights, slow fading depends on the capacitance

Yours Christopher
F4Z9P7VGO6UXY3S.SMALL.jpg
zupyo222 years ago
wow you are a genius
so i am working on a bike project that i want to replace the 3 old head lights with 3 leds and i want them to be hooked up to 3 toggle switches
the nly problem is that i am a newB at lighting and circuits so if any one could give me any ideas i would greatly appreciate it.
thanks.
121ck,43 years ago
Dose it work with IR phototransistors? or some else photo tranzistors .
I have conected everything but it dosent work jus leds lights and nothing more and i used IR photo tranzistor. Plz help me . my email riciuksss@gmail.com
Atvaizd0043.jpg
iminthebathroom (author)  121ck,43 years ago
That sucks! I'll dig up the exact photo transistor i used. Off the top of my head though, it wasn't a IR photo transistor, unless i am confusing my terminology. i have run the same circuit using a standard 2 leg photo diode, the type you can find at most radio shacks bundled in an assortment bag of 3-4. I used the 3 leg photo transistor as it was mega cheap on ebay for a large amount.
I tryed with 3 leg photo tranzistos and it vas the same
iminthebathroom (author)  121ck,43 years ago
Rats, thought it might have been something simple. It will be a couple of days to be honest, but I will try to get to it. i work 6 days a week, 12 hours a day so I am a little bit of a zombie by the end of the day -

Just a thought though, have you brought the completed powered circuit into a room of complete darkness? It might just be the sensitivity level of the photo diode/transistor you are using. when i first did the circuit, it wouldn't work. In frustration I left it where i was working during the day, in my back sun room. Later that night, i went to retrieve something from the sun room and low and behold the leds were one, as soon as I flicked on the lights it went out, flicked them off again and it began to glow. Keep in mind, the only lights that will keep the leds in the off position is sunlight, halogen or conventional. Fluorescent lights will have no effect. The photo transistor used in the instructable had a different sensitivity level and made all the difference.
no I had that in my mind but I didint try something like that but I don't think thats the problem becouse ven I conect to power source the leds jus turns on and stays like that no mater the photo diode is conected or not ... I used this circut...
F4Z9P7VGO6UXY3S.MEDIUM.jpg
iminthebathroom (author)  121ck,43 years ago
Any Luck? Biggest problem I had was on several of the pods i had wired the poles on the transistors wrong, which produced LED's on, all the time. Look at the hand drawing of the circuit, and try to visualize that circuit and yours, could one of the transistors be wired wrong, is the schematic different from what you see then in the drawing. I'm curious. If you do figure it out, make sure to include the fix here, to help others who may be having a similar problem
yes about that hand drawing I noticed that the poleritys c and e are
diferent from schematic that I whas bulding I will try soon and I will
tell you about it.
121ck,4 121ck,42 years ago
I tryed to swich poliarites of tranzistors and the same problem led's are glowing ://
I used http://www.evita.lt/show_doc.php?id=10920
an 3 kindes of photo tranzistors http://www.evita.lt/?pid=catalogue&action=search&keyword=fototranzistorius&submit=Ie%C5%A1koti
And the same ...
iminthebathroom (author)  121ck,42 years ago
That is so frustrating, sorry its not working for you. When i built this, I built the prototype much larger for visualization purposes. I will try to dig it out, just out of curiosity, where are you from? Reason I ask, is someone else was having problems and I ended up sending them a version of the circuit to use as a guide. Took a while though as they were from Pakistan, and I am from northern British Columbia, Canada
I am from Lithanian I would be wery thanful if you would help me to solwe this problem...
iminthebathroom (author)  121ck,43 years ago
Hmmm, perhaps it is the addition of the capacitor, all though in theory it should work. In step 4, I did right this spiel - Ah yes, its pod building time! Now you will have to bare with me as I built the actual circuits over a year and a half ago. Little embarrassed to say that I never properly learned how to draw a circuit diagram and it is next on my list. So I have included my bizarre 3d representation of the circuit picture #8 along with many photosPerhaps take a look at the hand drawn picture, second to last photo in step 4.  As all "real looking" circuit drawings were added after.  The diagram with the capacitor added, was from another instructable member.
dominic693 years ago
Nice instructable!

Just a question, how many milliampere is used?

Thanks
iminthebathroom (author)  dominic693 years ago
you would think i should know that... I'll have to look into it
I want to use another type of power source and I would like to know how the table consumes milliamps.

Maybe you can read information about your power source?

Otherwise it's ok, I'll test.

Thanks for your fast answer.
iminthebathroom (author)  dominic693 years ago
well, as in the instructable, i pretty much destroyed any information about it, when removing the case of the computer power supply to fit in the table. In theory though you could just add up the draw of however leds you plan on using, the draw of the other items used ie transistors should be negligible. use this as a basis, and give it a bit more power then you think you will need, the resistors will negate any issues of too much power
VISI3 years ago
nice work but look on you tube -panou cu senzori optici -that looks interesting
splazem3 years ago
Amazing!
aliberkman3 years ago
Great Instructable. Thank you for sharing. I have a question. With what type of phototransistor we can increase the distance of perception for phototransistor?
thank you
iminthebathroom (author)  aliberkman3 years ago
I am not sure to be honest, the phototransistors used are all ready very sensitive. Enough so that I had to add the black silicone tubes as sensitivity reducing sleeves, "its towards the end of the instructable" Reducing the height or removing the sleeves all together will increase the sensitivity.
1up3 years ago
I really like this, especially because I was going to make something exactly like this a while back. I had a circuit prototyped up that would light up the LED and fade it out when you waved your hand over it. I never got around to building enough to put in a table, though. Great job!
mpep3 years ago
Great Instructable. Love the idea.

As a thought, if slow turn-on was required (to make it look more analogue ;-)), a capacitor could be added across the first 2N3904's Collector and Emitter.
The 22k would charge it when the photo sensor detects darkness.

Just a thought. Haven't tried it yet, but should work okay.
mhkabir3 years ago
I suggest you add an opaque acrylic cover on top, instead of glass so that the LEDs are diffused and provide a better effect.
iminthebathroom (author)  mhkabir3 years ago
tried that several ways, it didn't work as well as i thought it would. I'll post some pictures one of these days
What about filling the panel with light diffusing material, like polyester quilt batting or something more flame-retardant, perhaps?
iminthebathroom (author)  broach3 years ago
Not sure if you noticed or not, but if you go down the comments i actually posted a picture of it when the glass had a sheet of velum under it. After a while i returned it to the raw leds though
iminthebathroom (author)  broach3 years ago
maybe, dunno
sdtacoma3 years ago
In the videos there is a pod of LEDs that always seems to be on. Is that the pod that is mentioned in Step 10 or is that pod on for some other reason?

Great work and great ible!

iminthebathroom (author)  sdtacoma3 years ago
Pretty sure it is, some of the other pods would do the same thing though from time to time. Different location different pods. It all depended on the lighting, this table really is susceptible to it the ambient light around it sometimes. Where we live there is a large aluminum smelter "alcan". The power is fed locally from a hydro power dam "kemano". Anyway sometimes when things happen there unexpectedly we get crazy power surges. Clocks speed up, lights brighten, but the table displays it in waves. Hard to describe, have to try to get it on video one day. Almost like a sine-wave
corkey1233 years ago
Awesome! Great instructable & idea :D
iminthebathroom (author)  corkey1233 years ago
Thanks!
ProCactus3 years ago
Th example video simple does not work, Segments don't light ?
I cant hear it as well, Sound is very bad.

No Interest in reading further.
iminthebathroom (author)  ProCactus3 years ago
thanks for the awesome and constructive comments
JermsG3 years ago
Typo note: In number 1, step 3, 'the non descript one on the left' should be 'the non descript one on the right'.
=8-)
iminthebathroom (author)  JermsG3 years ago
whoops yup, maybe I meant my other left!
Maybe someone has already said this, but if the switches are light sensitive and are hooked to led's, won't the turn themselves on and off? Maybe opaque walls between "cells" would be a good idea.
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