# Stronger Glasses

I made a pair of light up Kanye West glasses for New Years!

Firstly, I want to say that I completely ripped off this idea from my very talented friend Jordan.  The electrical design is mine, but the fashion design is all hers.  I highly recommend you pay her blog a visit to see what kind of other stuff she’s cooked up.

## Electrical Design

This was my first time dealing with audio from scratch.  I have designed a few filters in school, but never carried them all the way out in a real world application.  You can see my schematic here (click to zoom):

The audio signal path has a few stages:

### Gain

Right off the microphone, the signal is given a half-rail bias (provided by U1D) and sent through a gain stage.  I used an inverting amplifier because it will provide an “infinite” input impedance to the extremely weak microphone audio signal.

Having never dealt with an electret microphone before (besides my ch00f-o-scope which hardly counts), I didn’t know how much gain I was going to need.  Being lazy, I simply configured a single 10k pot so that the brush contact connected to the inverting input of U1A and it alone provided both resistors.  This is a good lazy solution if you need a gain of 10 or 20.  For a gain of 200 though, it proves difficult because you need to carefully turn the pot until the resistance on one side is 1/200th the resistance on the other.  Basically, if you split the 270 degrees of turning motion of my pot into 200 segments, you need to turn it to just one segment before the end without touching the end.  This is basically impossible, so I did a last minute re-work to make it as you see it in the schematic.

### Low Pass Filter

This stage is pretty straight forward.  The passive LPF’s cutoff frequency is determined by:

Freq = 1/(2*pi*R*C)

In this case, that’s around 50Hz. This way, the glasses will only “hear” the base.

### Envelope detector

The goal of an envelope detector is to give a voltage output that is proportional to the amplitude of the waveform input.  As you can see in this graph, the green waveform is the audio, and the blue waveform is the envelope:

Fun fact, AM (or Amplitude Modulation) radio uses an envelope detector to turn the amplitude of an EM wave into the audio waveform that you hear (the actual carrier frequency is much much higher than the audible band).

A passive envelope detector simply passes the audio through a diode and into a capacitor/resistor pair.  The idea is that as the waveform voltage increases, it will charge the capacitor through the diode, but when it decreases, the capacitor will be unable to discharge through the diode, and must instead slowly discharge through the resistor.  The time constant of this pair needs to be fairly long or you’ll end up with another waveform instead of an envelope.

EDIT: I noticed during the construction of my LED Jacket that the RC pair I have here is actually pretty darn big.  As is, the time constant is .5 seconds.  This means that after an impulse (a beat), it might take over two seconds (5 time constants) for the lights to die down!  Actually, this isn’t quite true.  If I had tied the capacitor to the VCC/2 rail, that would be the case.  Because I’m tying it to ground, I never give the cap a chance to discharge all the way.  It will drop very sharply from its peak voltage down to VCC/2 and then stay there.  The cap will discharge most quickly while its voltage is high, so instead of taking 5 or so time constants, it really takes less than one.  To compensate, I needed a very large RC time constant in this circuit.

Here I am using an active envelope detector.  The only difference is that the diode is placed inside the feedback loop of the opamp.  This prevents you from having to deal with the .7v drop across a standard diode.  The opamp will compensate for that.

The output of the envelope detector is no longer an AC waveform, but rather a DC-ish voltage level that will be somewhere between 1/2 rail voltage (silent) or full rail voltage (really loud).

### Comparators

The output of the envelope detector is passed to six comparators that compare it to a threshold value set by the tree of resistors.  All of the resistors in this tree are 10k except the top one which is 100k.  Because of the limited voltage swing of opamps, the envelope waveform (and the audio waveform for that matter) will never reach the top rail, so I wanted to drop the highest threshold down to a more manageable level.  It didn’t really matter anyway because I could always change the gain on the gain stage to compensate.

The output of these comparators is open collector meaning that they are high impedance when off and a current sink when on.

### TRIACS

As you’ll read later, EL wire operates on a high-voltage AC supply.  TRIACs are switches used for switching (often high-voltage) AC signals on and off.  They are switched on by a current passing into or out of their gate, and they switch off again once the current through the TRIAC is zero (this happens twice a cycle).  In complicated applications, they can be used to attenuate AC signals (like PWM can attenuate DC signals), but in simpler applications, a continuous current out of the gate will keep the AC running, and no current will stop it.

Most TRIACs require some kind of opto-isolator part to prevent any high-voltage stuff from accidentally frying your more sensitive components (an opto-isolator is literally an LED and a photodiode in a single package.  There is nothing conductive connecting the input and output).  I found a part that claims that no isolation is needed.  It’s a non-stock part on Digikey, but incredibly useful while they’re in stock.  As long as current is flowing from the common node out of a gate, this TRIAC will allow AC current to conduct from the common node to the output node.  They’re also three TRIACS to each chip, so that’s nice too.

It’s kind of hard to see what’s going on in the schematic because of how I split up each gate, but you can see on the right side that the outputs of the comparators connect to the gates of the TRIACs.  On the left side of the schematic, you can see that the common node is connected to the positive voltage rail.  This is to ensure that the comparators can exert a negative voltage on the gates and suck current out of them.

### Power supply

Each strand of EL wire that I ordered came with a power supply.  Rather than trying to build my own, I figured I’d keep the supply intact and simply use my circuit to switch it on and off.

I connected the live terminal of the supply to the “LIVEFROMPSU” terminal and the neutral end to the “LIGHTNEUTRAL” terminal (the VCC rail).  Technically, I could have just connected the live terminal straight to the EL wire, but I wanted the opportunity to place a very large resistor between the terminals of the power supply.

I believe these supplies are resonant supplies, and without some kind of load, they will build up a charge somewhere and eventually break down (think of that video of the bridge resonating and exploding).  This added resistor provides a dampening effect that will prevent damage.  Expecting there to be times when my glasses are totally off (when it’s quiet), I wanted to provide some minimum load to protect the supply.

I’m not sure if this is entirely necessary, or if 470k is even the correct value, but so far the supply still works.

## Mechanical Design

Unlike most of my projects, the mechanical assembly of these glasses was more of a pain than the circuit itself.  This is mostly due to the EL wire.

### EL Wire

EL wire, or “ElectroLuminescent wire” is weird stuff.  There are two conductors separated by some kind of fluorescent material.  The two conductors act as a long capacitor, and passing a high frequency, high voltage through this capacitor causes the phosphorescent material to light up.  Unlike most light-producing components, DC current doesn’t really pass from one terminal to the other.  They stay isolated throughout the entire length.  You can see a cross section here:

There are a limited number of colors for the phosphorescent layer, so some of the colors (like the red and pink) just have a blue inner layer with a colored outer layer that reacts with the blue to produce the desired color.  Think of how some pigments react with UV light.

Let me just say that stripping EL wire is a pain in the ass. I developed a few techniques, but never really mastered it.  The real issue is stripping the clear layer carefully enough to keep the outer conductors intact and not strip the coating off the inner conductor.  I found that heating the wire with a flame could sometimes help loosen or soften the coating, but it still typically took me at least three tries every time.  I recommend investing in WAY more EL wire than you plan on using.

### Glasses

For mounting the EL wire, I simply drilled some holes in the glasses and slipped the stripped ends of the EL wire into those holes.  A single dot of super glue keeps the wire from sliding around on the shade.

EL wire operates at around 100V or so.  The current is low enough to prevent injury, but that high of a voltage can produce a rather painful shock.  I had to be careful when designing the glasses to not allow both conductors to touch my skin.

If you recall from before, for each wire, one of the conductors is traveling straight to the power supply while the other is switched on and off by the TRIACS.  Those going straight to the supply are all tied together, while the others are tied individually to my board.  At first, I thought there was some importance to the polarization of the EL wire and tried to maintain the polarization used in the power supply I was provided.  With this orientation, the inner conductors were all tied together while the outer conductors were connected to the power supply individually.

Mechanically, this was an issue because the outer conductors are extremely fragile, and any sort of tugging on the wires going to my circuit would break them.  To fix this, I reversed their roles. I tied all of the outer conductors together, so that all of the strain was going to the stronger inner conductors:

The connections on the inner conductors were wrapped safely in electrical tape to prevent electrocution of my face.

Here’s a schematic doodle:

To bridge the nose, I simply connected the inner conductors of the wire on one side to the inner conductors on the other.  All of the outer conductors were tied together for stability and redundancy.

All of this wiring is out of my field of view (as if you can see anything out of these glasses anyway), and above the nose piece, so I actually can’t feel it at all.  I’m a little weary of folding the glasses though as the wiring on the right side is a little tight.

## Conclusion

I was in a super big hurry to finish this project before New Years, so I was a little hasty with the design.  There are numerous ugly reworks of my circuit, and as you can see in the image above, I wasn’t too concerned with aesthetics when cutting a hole out for the gain adjustment knob.  The circuit will sometimes enter a mode where all of the lights turn on regardless of incoming audio which can only be fixed by power cycling.  I’m not entirely sure why that is, but if I was planning on using these again, I would just redo the circuit entirely.  After all as I said before, the glasses were the hard part.

The sound reactive effect of the glasses is really a sight to behold.  I’m super impressed with myself.  Enjoy!

## Edit:

So it’s “Maximum UV Protection” for the parts that are actually…opaque.

Well, it was a wild and crazy night.  I got a lot of compliments and one guy offered to buy them off me for a whopping $20! Here’s a pic of my friend and I right before heading out (she’s got pretty cool glasses herself): ## Bill of Materials For those of you who want to try making these on your own, here’s a bill of materials. All you really need are the “DIGIKEYPARTNO”s. It’s in .csv format. I had several requests for photos of the circuit board, so here they are: Relevant Reader Mail: EL wire circuits advice Schematic Stronger Glasses For more on EL wire power supplies, click here. For more on EL panels and dimming EL materials, click here. Project files can be found here: Stronger Glasses package v1.0 ## 146 thoughts on “Stronger Glasses” 1. you guys are joking, right? he just explained in detail how to make one. you have all the information you need! go forth and make! 2. Many of us are not electrically inclined, so we pay others for their talent. He should patent this and they’d sell like hotcakes! 3. I need 6 of them!! Pleeease.. 4. nice keyboard! 5. hi, im looking at doing something very simlar to this with EL, but on a very short time frame, do you possibly have a pcb file for these i could have? 6. Wow! Please let me know if you would ever be able to make these for a price. I would pay a lot of money to have these designed. Thanks! 7. That’s a brilliant design! I think I might be a bit jumpy though, with 100V waiting to nip me on either side of my face. 8. wow these are pretty nice, email me if you do start hawking these at a fair price 9. You need to create a kickstarter project to sell these. I would very much like to give you money for a pair. • Came here to say this. Put this on Kickstarter and make some money if it catches on and don’t lose anything if it doesn’t. I’m pretty sure there are more people out there that aren’t as tech savy as you are and would still appreciate some fun party glasses. Go for it, you’re on to something great here! 10. Also, a guy offered$20? I bet you could sell them for upwards of $100. Easy. Sell em for$60 and you’ll rake in over a million.

11. Same here. Selling these would make you a LOT of money. Also, I would buy some.

12. Great Job, great explanation, thank you
If you decide to build your own EL inverter, it can be done using a square wave generator (555 timer) at 1.2Khz, and putting the ~5V output signal through a transformer in a step-up configuration. The 42TU003-RC tranformer from Mouser works perfect

• great help!

• I put together a pair of these recently, and they are incredible.

Decided to make my own frames with my 3D printer and just published them to thingiverse. check it out: http://www.thingiverse.com/thing:16008

the nice thing is that the holes are built into the frame, and the bars that run along the glasses are recessed to allow the EL wire to sit flush with the frame.

The circuit i put together used the LM3914 bar display driver IC, which does a similar thing to your circuit. its a constant current device designed to drive LEDs, since optocoupler use LEDs it worked perfect.

thanks again!

• I’ve actually never heard of an LM3914. Very interesting part. You probably don’t want to feed your audio signal directly into it though because it might behave sporadically at certain frequencies. For example, if you play a 1.2kHz tone (same frequency as the EL wire’s AC), you might be turning a TRIAC on at the same point in the AC wave every period and end up with an odd aliasing effect.

For an application as simple as this, it’s probably not a big deal, but in the future, you should at probably include an envelope follower like the one I made.

13. The market for these glasses are huge!! You better patent the design before someone else takes it and makes millions off it (if they haven’t already sprung into action)

14. Hi, Amazing job on those glasses by you and the design of your friend!
If I were any good at electronics I would be making it myself right now.

I’m good at writing software not at making cool hardware like that.

You could probably mass market this at 20 Euro/Dollar per piece. I would be willing to buy one now for 50 dollar if you are up for making another one.

If you are up for it, give me a way to contact you for payment and shipment please!

15. Can you take some snapshots of the actual wiring? The inside of your hammond? Part # and list would be awesome. I don’t know which model U1D you’re using, the blog says all 10k resistors except one 100k resistor but I see﻿ some 50K, 2.5K 20K, 30K entries on your schematic, as well as the bleed resistor. Obviously 2 of those non-stock TRIACS pieces per glasses pair… in the final pic is that a 9volt, a 2-AA power supply, and the Hammond?

• If you look closely at the opamps and comparators, you will see their part types. For example, U1D is an LM324. And it looks like you caught a typo. The highest resistor in the resistor tree is supposed to be 100k instead of 10k. I made this change while I was tweaking and forgot to update the schematic. It’s fixed now.

And you are correct about the last picture.

• Hey just a few more questions and I will be okay (for now!)

I found no C2 or R4 entries, I’m assuming this is just a numbering accident.

Out to VCC is Negative terminal on the AA PSU? and out to VCC/2 would be going to the negative terminal on the 9v?

Can you explain the M1 entry? the symbol looks similar to a capacitor, but I’m unsure of what I’m supposed to do there.

Lastly, I can see the op amps and comparators and your pot there in the schematic, It seems the mic input should enter the circuit before the op amps, but i don’t see a line in from the mic anywhere in the schematic. Possibly a model on your electret, because i’m not sure if the type matters?

• I guess C2 and R4 went to component numbering heaven. You’re not missing anything there.

The AA PSU is AC, so it really doesn’t have a polarity, but you can call one terminal “live” and the other “neutral” if you like. The important thing is that whichever one you connect to the circuit is connected to the positive terminal so that the comparators can guarantee negative voltage and pull current out of the TRIAC.

Think about your last two questions together, and then try to figure out what “M”1 is 😉

I used a standard -44dB, 2.2k electret.

• Well spend money, this is going viral!
I’m studying at a technical college in Sweden and your work is really inspiring!

Looking forward for more cool stuff in the future!

16. Eu quero um desse, quantos que vc cobra pra enviar aqui no Brazil ?

17. Very nice indeed!! I’m quite interested in doing this myself. Is there any chance that you have a “grocery list” of the different components laying around? 🙂

Keep up the good work!!

18. nice post!
thanks being so clear!
I’ve never tried to play with ElectroLuminescent wires but this is a good workaround!

19. Those are sweet! If you are looking to create and sell pairs please email me!

20. AWESOME !!!! Do you sell them somwhere or what? I would like to buy 10 pairs for my close friends! (email me)

21. I saw this on television and I hope you are going to sell this, because I definitely want a pair 😀

22. Where did you get the EL wire? I’m trying to find it online and I can only find individual colors

• I’m not certain I understand what you mean. I purchased five 10-foot strands of EL wire and cut them down to length. I have tons of extra that I might use for other projects.

23. I hate to bombard you with questions, but as someone who would love to try this project out I have a few. First is easy, what thickness EL wire did you buy.

Second is there any chance you may be able to do a tutorial on how to wire up the circuit for those of us who are less electrically apt than you? It would be much appreciated. I’m loosing you on how to connect the Triac arrays.

Awsome project, I hope I’ll be able to end up with something close to that cool.

• Not at all. I appreciate you taking the effort to understand. Most people just want to buy it off me completed.

The EL wire is 2.3mm.

The TRIAC wiring is a little confusing because of how the chip splits up the individual TRIACS. Usually a TRIAC has three nodes: the AC current passes through two of them, and the third is the gate. The TRIAC is switched on when current is pulled out of the gate. Because it is assumed that all three of the TRIACs in this circuit are on the same supply, there is a common node among them. This was hard to represent in EAGLE, so I ended up making each TRIAC chip into four components. Each individual TRIAC is a two terminal device (the gate and one side of the TRIAC), while the fourth component is the common node which can be found on the left side of the schematic connected to the positive power supply. If you look at the datasheet of the TRIAC from the digikey page, you’ll find an example circuit that should help you out.

As far of the rest of it goes, it should be pretty straight forward. Just make sure you read your datasheets and pay attention to the pinouts. I’ve never really believed in straight up tutorials, because half of learning engineering is learning how to problem solve, and you’re not going to do that by just following instructions.

Good luck!

24. How much time do you spent to make these glasses ?

And is it diffelcute to make these glasses ?

• Took me about two days.

It’s pretty hard if you’ve never done any work with PCB layout, PCB etching, or surface mount soldering.

• I don’t believe in tutorials. If you’re going to make a pair of these, I think it’s best that you first understand how/why they work. My post along with thousands of resources out there should help you to understand them, make your own, and even improve on the design!

25. if you dont market these you are missing a massive trick they will sell shitloads otherwise someone else will nick your idea and make shitloads
(it happened with the airbag inventor!)

26. Hey, I’m a second year electrical engineering student and I’m really impressed with your design! I’m assuming you are an EE, or have had EE course experience, and I was just wondering what level of coursework prepared you enough in order to make a schematic like that from scratch? I ask because I’ve taken intro to circuit theory/digital design, and I feel like even though I’ve technically been exposed to many of the parts you’re working with, I wouldn’t know how to apply them very well. What do you think?

• The secret is lab classes. Everything I needed to know to make this circuit, I learned from a power electronics lab. In fact, everything I remember from college I learned in some kind of lab class. TRIACs were part of our course curriculum, and just getting anything to work required some fundamental understanding of op-amps.

The icing on the cake is that I deal a lot with audio as part of my new job. For a lot of circuits like this, there are just “right ways” to solve problems. If you were to rip apart one of our products and look at the VU meter, you would find a very similar circuit. That isn’t to say I just copied it. You still need to understand how something works to make it work for yourself.

Try taking some analog signals classes and start playing around with LTSpice. I actually modeled this whole circuit in LTSpice before starting.

27. I’m hoping to do this project, possibly as a good present for one of my friends. After that (if I pull it off and learn a little more electronics to understand), I might make a step by step guide and post it (I might change some parts).

Would this be ok if I give credit to you and Jordan?

• Absolutely. Maybe then you can take on some of the oodles of people asking me to do the same!

• Hodge, I’d love to tag along and learn what ever you do from making this project. Aside from which way to plug in a battery I really have no experience in how this was made haha! If your ok with it lets share contact info, I’d love to learn how this was done.

ch00f, do you hold any copyright on this design or are you planning to? It’s clear there is a market for it, and with a bit more tweaking you could make a sleeker design that intrigues investors and could lead to a marketable product. If this is something you’re considering please comment below. Thanks to you and to Jordan for adding some usefulness to Shade Sunglasses haha

• The design does have a Creative Commons license held by Jordan, so you can make your own, but you cannot profit from the design. Anyway, there is nothing particularly clever or complicated by the design, so I have to think that if there was any kind of market for this device, it would already be saturated.

Besides, I just do this stuff for me. I have a day job which provides me with all the funding I need.

• Sorry for the late reply, school has started up and I’ve put some things on hold. I’m thinking this will be a good spring break kind of project. I’m not sure if I’d share contact info though :(. My hunch is that it would be ok, but I’m still really want to be cautious in general (especially since others could see the info in this post if I posted it). If I manage to pull it off though I’ll definitely post it somewhere 😀

Sorry that I can’t be much help, but good luck with everything 🙂

28. One week of research later, I think I understand the bulk of the circuitry.

Two more quick questions though. First off what exactly is the VCC? From what I can tell it’s the power for the opamps, but where is that coming from. Is that an power source external from the inverter? Right now I’m assuming that you have a power inverter powered by whatever it happens to be, and a 9volt battery that powers the opamps. If this is true, why is there a connection on the schematic between the VCC and the ultralight?

Second if you wouldn’t mind sharing, from where did you purchase your EL wire? I’ve found several places, but you mentioned getting an inverter with each segment of wire, which is a sweet deal.

Thank you for this write up and continuing to answer so many questions. Working through this over the past few days has been a truly rewarding experience.

• You are correct, the opamps are powered by a 9v battery (VCC). VCC is connected to one of the inverter lines because otherwise, it would be impossible to turn on the TRIACs. TRIACs are weird because unlike most components, they are current controlled instead of voltage controlled. A TRIAC is turned on when current is pulled out of its gate. If there was no connection between the inverter and VCC, you could not guarantee that the comparators could pull current out of the TRIAC’s gate. The TRIAC would be “floating” in that case. You can see an example circuit for the TRIAC set in the data sheet.

Keep in mind that the comparators have “open collector” outputs so they are either pulling their output to ground or not exerting any potential on it. They cannot pull up.

As far as the EL wire goes, shop around Amazon. Mine was even Amazon Prime elligible.

29. You advised in the build details to use a
311-50KGRCT-ND – 50k 0603 resistor 5%
I couldn’t find this on digikey. Do you mean
311-51KGRCT-ND – 51k 0603 resistor 5%

Charles

• Haha, indeed I did. I just noticed that bug in my library yesterday when I tried ordering parts for a new project. Nice catch!

30. Dont worry I thought I was going crazy trying to find the parts.
Any chance of getting a pic of the finished circuit layout? Keen to try and build one of these

And 1 other thing on the sheet if anyone is trying to work out the part numbers
B1551LBK = 1551LBK
Digikey Part# HM909-ND

• Sorry, but I actually don’t have a layout to go with that schematic. A lot of the schematic was changed after I printed the board, and I applied the changes as hand-reworks. Besides, the original layout was never very spectacular to begin with. I was sort of in a hurry to finish this damn thing.

31. hi i am Rene(26) from Slovenija. i like it very much,i try to find something similar in all cinese web shop but nothing,
did you start to produce it?

• Sorry, I will not be producing these glasses and they are not for sale. If you would like a pair, try to make them!

32. If I’m trying to build it as a through hole board instead of surface mount, I should be fine as long as I match the specs of each component to one of equal or better values right?

• Ha, I don’t really know what you mean by “better”, but it shouldn’t be a problem. Nothing on the board is terribly high frequency that would cause issues with through hole. You’ll just have to find a different TRIAC because mine is surface mount only.

33. By “better” I meant that the capacitors I found with the same capacitance and tolerance have a higher voltage rating, but as far as I know with capacitors you’re fine as long as your desired voltage is under that which it is rated for.

34. Oh I really love this blog. I’m going to make a pair of these with my father. I hope this works because i really love the design. Thx you’re a real boss

35. I want at least one pair of these glasses! I can buy few pairs if that helps. What you think?

Cheers from Finland 😉

36. Hello,
Just a question. You say you used a LPF to detect the bass frequency of around 50Hz. However from what I can see you used a resistor of 30k and a capacitor of 1uF which would give 5.3Hz according to the equation. Is this a typo or am I missing something.

37. Love these glasses and am working on prototyping a set for my hip hop group. Looking at your schematic I’m unclear as to the value of Vcc/2. I would think it is half the input voltage but I’ve also hear it could mean -Vcc?

38. i was going to try to build a pair of these as a project, but after reading this i have discovered that the building process is A LOT more complicated than i thought it was, i would love to know how much i would need to pay you to build me a pair.

39. On the schematic, the PSU from the EL wire goes through a 470k resistor and into the positive voltage rail, (and I assume the VCC for the chips is that 9V battery in the pics?), but won’t that voltage be AC if it’s coming from the EL wire PSU and damage the comparators and the LM324? I’m sure i’m just missing something really simple, my understanding of circuitry is far from good.

• Keep in mind that the PSU’s ground is not connected to my circuit’s ground. In fact, when it comes to the AC signal, there really isn’t a “ground” per se because the signal is constantly changing polarity. There’s a “live” and “neutral” (arbitrarily chosen by me). The “neutral” is tied to my circuit’s +5v rail.

The TRIACs are switched on when current is drawn out of their gate, and the only way I could ensure that would happen is by keeping the average EL wire voltage higher than my circuit’s ground so that my comparators pull the gates lower. I essentially “grounded” the EL wire to my positive rail.

Furthermore, a 470k resistor is pretty darn big. 100 volts across a 470k gives you .2mA of current, so there really isn’t any danger of messing up the circuit. This .2mA of current (I think) is enough bleed to keep the resonant circuit in the power supply from blowing up.

• Ah thank you so much! This is the first circuit i’ve looked at using AC so i wasn’t sure, but that completely makes sense! Thanks! One last question, where the schematic asks for a VCC/2 rail, i can put 2 resistors between +9 and 0 (of the battery) and that will give me that 4.5V at the junction between the 2 resistors right?

• It will, but you need to buffer that 4.5V signal. Otherwise, as soon as you pull any current out of it, the 4.5v voltage will sag.

Take a look at R1, R2, and U1-D in my schematic.

• So R1 and R2 splits the voltage and the buffer amp keeps it at VCC/2? So then on the schematic where it has the arrow going to VCC/2, is that indicating THAT part of the circuit is at VCC/2 or is that saying that needs to go to another VCC/2 point and that’s created with another voltage divider with a buffer amp? Sorry for all the dumb questions!

• Sorry, I can’t reply more than 5 deep, so I’m replying to your comment farther down.

The all of the VCC/2 arrows are connected together. There is no need for another voltage divider/opamp buffer.

40. Heya there!
I would -love- to get one of these pairs. If you could toss me a e-mail to Hannesahlvin@hotmail.com , I’d be willing to pay $300-500 + postage if you could hook me up with a pair. I’d like to “disect” it and try to figure out how to build it that way. I’m just a freshman in high school, so the schematic that was published is a bit hard for me to understand since I’ve never done any technique. 41. What did you use to combine the common nodes on the glasses? It looks like a straightened paperclip that everything is soldered to. Is that right? Correct me if I’m wrong, but I’m assuming that the bottom line of el wire corresponds to Light 1 on the diagram • It’s just a piece of solid-core breadboard wire that I stripped the insulation off of. And, you are correct. The bottom most light is the lowest light on the diagram (it takes the smallest amplitude to illuminate). • Thanks for answering! I have a couple more questions, hope you don’t mind. Does C8 just act as a peak rectifier in the envelope detector? So the opamp right beside it (U1C) just acts as a buffer? Also what is the voltage rating on the electrolytic caps that you use? I think the digikey part number you suggest is at 16V, but the ones in the picture look like 35Vs? Thanks again! • The digikey part numbers I listed are the parts I used. What about the schematic leads you to believe that they are 35V caps? Also, I don’t know what you mean by “peak rectifier”, but C8 and R5 together create an RC filter that acts as a low pass filter. There are more details in the section called “Envelope Detector”. 42. <> So you say that inner and outer conductors can be inverted and it sitll works the same ? Even with dealextreme inverters ? • Yep, it should work fine. I only chose my orientation because it helps take the strain off the fragile outer conductors. 43. It’s May and you still don’t have a Kickstarter project for this. Why? At$120 a pop you’d get several hundred thousand dollars. Easy.

Make it happen.

• Sorry, I’ve got a job. Don’t really need any more money. Too much work. Besides, I’d rather spend my time solving new problems rather than rehashing old ones.

44. I don’t even know how I ended up here, but I thought this post was good. I do not know who you are but definitely you are going to a famous blogger if you aren’t already 😉 Cheers!

45. those glasses look wicked, I am going to make them. I got my el wire soldering tips from elwireinfo.com, that had some pretty good info and tips.

46. Pingback: EL Wire Glasses. « NU wild hacks

47. i know you wont sell these… and i am willng to make these myself, i just need some help… i am not an electrical engineer or have any experience in that field… i am still in school u see… it would be really a big help if u could reply with the list of things needed to make these glasses, i’ll get them and start making them from scratch.

48. Hey, awesome project. I was wondering what changes would need to be made for just one string of EL wire? I am a simple man, just want a wire that pulses to the music (and those pre-made sound activated drivers are pretty bad).

49. Hey, dumb question. Why is the “threshold” voltage going into the positive input of the comparators? From my tenuous grasp of these things I was under the impression that the positive input going higher than the output triggers the comparator to output the voltage. So I guess in my head I figured the positive should be the one that is changing with the audio value, could you explain?

Thanks

• The output of the comparators are open collector meaning that a “low” output pulls the output to ground while a “high” output does nothing. The triacs are activated when current is pulled from their gates, so you want to activate them by pulling them low.

• Ah ok I gotcha. One more question, I am looking to use through-hole parts, so I guess I should get one of those optocouplers, although most of the ones seem to be in the same package with a TRIAC output, so I wanted to make sure that would work as long as I match the specs with the TRIAC you listed?

• If the TRIAC built into the opto-isolator can handle 120+ Volts, it should work just fine. Though I think some of those opto-isolators have low-voltage/current TRIAC outputs meant to drive the gate of a larger TRIAC, so be careful with that.

50. Hey, sorry but I do have one more question that I just can’t figure out. I built the circuit, everything worked great, but then after a while the EL wire would just always be on, and I tested the comparator and it was constantly outputting the full voltage, and would decrease a little with input from the mic (from the ~9V to 8 or so), but never drop to the 0V which is needed to pull the current through the TRIAC gate right? I have changed out the comparators and it still happens, even rebuilt the circuit a few times with brand new parts a few times. I am using the same TRIAC you specified, so it shouldn’t be getting fried from the AC right, since it has the built-in overvoltage protection?

Any suggestions? Thanks again for the help, I have learned a lot attempting this project.

• Hmm oh ok, thats interesting. I’ll have to acquire some more parts and try again. Thanks for putting up with me haha. I think I’m finally learning the stuff I probably should have learned in mechatronics.

51. HI, WOULD LOVE TO GET A PAIR MADE FOR MY SHOW. DO YOU OR YOUR FRIEND MAKE THEM? OR A NYTHING ELSE FOR MY LIVE SHOWS? 🙂 THANK YOU