Hi Folks,

I'm new to the forum here, but it seems like the ideal place to seek help with my new project.

Essentially what I'm trying to do is build a cool Halloween costume. My idea is to make a jumpsuit that is covered in LEDs that light up when loud noises happen. I'll be at a concert this Halloween and my vision is to have all of the LEDs light up whenever the bass hits.

The general idea is that the sound will hit a microphone which is attached to an amplifier. The amplifier will send output to a circuit with a couple of transistors that are wired so that they will only allow current through the circuit when the amp puts out a large enough signal. When the amp puts out a big enough signal, the transistors allow current to pass from a battery pack to a large ribbon of LEDs that are attached to a jumpsuit that I am wearing while dancing/drinking/scoring-with-innumerable-chicks.

The amp has a volume control potentiometer so that I can fine-tune it according to the volume of the sound that the mic needs pick up for the LEDs to work as desired.

Here are my materials so far:
One Jumpsuit
Two Electret Mic Amps
Two Electret Computer Mics
This LED-control circuit diagram

I still have to buy:
Two 16.4 ft waterproof LED strips
Two 8-D Cell Battery Holders

My problem (and the reason that I'm seeking help on this forum) is that I know just enough about electronics to be dangerous without actually understanding the precise details what is going on...

I have two of all of the electronics components listed above because I'd like to build one independent sound reactive circuit for each LED strip, then attach them both to the jumpsuit. That way if one of them fails, I'm still in business.

Right now the plan is this:

Remove the electret mic that comes attached to the Electret Mic Amplifier and replace it with a 3.5mm stereo headphone jack. This way I can plug a computer mic (that's affixed to my head with a headband or something similar) directly into the board. Then I'll attach another 3.5mm stereo headphone jack to the speaker output leads on the amplifier circuit board. From this output 3.5mm jack, I'll run a cord to the input of the LED-control circuit.

Next, I'd like to build the LED control circuit shown at the circuit diagram link above. Slight modifications will be necessary, of course. (This is one area that I'm going to need help with.) The first thing I'll change is replacing the male 3.5mm plug that is shown in the diagram with a 3.5mm female jack for input from the amp. That way, if something goes awry and things start getting yanked/dropped/separated-from-the-other-components, the male to male cord that is used between the amp jack and the LED-control circuit jack can be easily separated from either component without damaging soldering points, etc... (I plan on drinking quite a bit while I'm wearing this suit and I want to be prepared for as many contingencies as possible.)

Next, I'll figure out exactly how to connect the LED strips to the LED control circuit and the battery pack. I've ordered the LED strips, but the company (LEDwholsalers) is taking their sweet time shipping them to me. Once they arrive I'll be able to tell if they're wired in series or parallel, how the power supply is supposed to be connected, etc... I'm sure that I'll need some kind soul on this forum to help me with this as well.

After I've figured out how all of this can fit together and I get it all working as desired, I'm going to start figuring out ways to attach it to the jumpsuit. Already, I'm fairly sure that I'm going to wind up cutting the ends off of the LED strips and attaching the leftover portion of the strips to my arms (they are made for cutting like this). I'll probably need help with figuring out how to attach the power supply and LED control circuit to both the long portion of the LED strips and the shorter portions that were cut off and attached to the arm of the jumpsuit. The battery packs, LED control circuits and mic amps will go in a waist pouch (or pouches) to minimize their vulnerability to spilled drinks, errant concert food, and the wildly flailing arms of my fellow concert goers.

Right now, I would love any general advice or critiques on the project. Are there any glaring problems with the LED control circuit diagram that I linked to above? Should I know something about the wattage or amperes of the LEDs or circuit or the compatibility of the two (specs are listed on the links provided above)? And most importantly, is there an easier, cheaper, or better way to do this?

I appreciate your time in reading this. Thanks in advance.

 

Hello,

The circuit you gave will not work properly.
I made a sound to light some time ago with (our member) fenris.

The lamp can be replaced by the leds with the corrosponding current limiting resistors.

Bertus

 

Thank you for the reply and advice, Bertus. I searched the thread that you referred to and found it. It looks helpful, especially with respect to figuring out which resistors to use in this project.

My main problem right now is the simple fact that the schematic that you posted far exceeds my comprehension level and my abilities at the moment. This is the case with 99% of the other schematics for this type of project that are posted across the internet as well.

Also, the circuit that you posted is entirely self-contained. Of course, this is good design philosophy, plain and simple; however, because I'm not very experienced at building circuits, I figured I'd be better off buying as many pre-constructed components for this thing as possible (the mic amp, the LED ribbons, the 12v battery pack), building a simple LED control circuit myself and then linking them all together. This way, I cut way down on the complexity of the project and keep it all within the scope of my abilities. There's no reason for a fool like me to try to reinvent the wheel (or the Electret Mic Amp, in this case) when there's a perfectly good one for sale for cheap on the web. While I may be able to build what you have posted after much studying/trial/error/headache/heartache (and, yes, ultimately, it would be better than what I proposed above), I know that it wouldn't be done in time for Halloween and it would probably end up being more expensive for me in the end due to my inexperience and lack of knowledge.

Looking back at the LED-control circuit diagram that I linked to in my first post, I realized that it didn't include any details about the transistors involved. They are both TIP31 NPN Silicon transistors. Here's the data sheet for them.

Is there any way that I can keep the Electret Mic Amp components that I already have and modify the aforementioned LED-control circuit (or build a different, but equally simple one) to control the LED ribbon? I need to preserve as much simplicity in this thing as possible.

Thanks for your time and help with this.

 

If you're looking for simple look at this:
http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=VS1
I don't know what your load (leds) but we can work around it.

 

Hello and welcome, 73 fat chick.

Replace your parts list with a bib, put it on, and see:

----> http://www.dealextreme.com/search.dx/search.t s shirts

 

Externet and gerty,
Ya'll are awesome! These are the exactly kinds of things that I'm looking for.

gerty,
You read my mind. Last night I found a similar product and I purchased it. I think the one that I found might need less mods for the load required for my LEDs.

Here are the specs for the LEDs:

LED Type: SMD 3528

Number of LEDs: 300

View Angle: 120 degrees

Lumen: 900-1100 Lumens

Watt: 24 Watts

Input Voltage: 12 Volts DC

Current: 2 Amps


Here are the specs for the relay circuit that I bought:

Supply Voltage: 9 - 15 Vdc (e.g. CFE002)

Current Consumption: 2 - 60mA

Input Signal: 10 - 300 mV

Frequency Response: 30 - 17,000 Hz

Output: 1 x SPDT Relay

Maximum Output Load (Resistive): Up to 240Vac or 28Vdc @ 5 Amps max. (Relay Datasheet)

Relay Connections: NO, NC, C (Relay FAQ)


I figured that because the LEDs required 3 Amps to work and this device's output was up to 5 Amps, they might be compatible right out of the box. What worries me is that the specs for the relay circuit also state that the output is "up to" 28Vdc and the LEDs require 12V. If it'll work at "up to" 28Vdc, does that also mean that it'll work "down to" the 12Vdc that I'll have powering my LED ribbons?

If you can somehow tell that these two devices won't be compatible from the specs and/or link provided above, please let me know and I'll see about canceling my order and start looking into buying the circuit that you posted above. Also, I really, really, really appreciate your offer to help guide me through the necessary mods. I'm not great at figuring these kinds of things out on my own yet, but with a little help and guidance, I'll be golden.

Externet,
The link you provided is great! I've seen similar products advertised across the net, but they were all prohibitively expensive and typically incorporated crappy/cheesy designs. The stuff at this site, however, is cheap enough and some of the designs are cool. Originally, my idea was to make the LED ribbons on my jumpsuit function like a VU meter, but I quickly realized that this was going to be far outside of the realm of possibilities until I gain MUCH more experience with building circuits. Now with the bibs listed at this site I can still incorporate a couple of small VU meters onto the jumpsuit to add yet another dimension to the LED-ribbon light show without much hassle or expense at all. I'll probably put one on my back and one on my chest.


Thanks for both of your responses. I was getting a little discouraged about the whole project until I read this.

 

I think it might work, why don't you sort of clip-lead together a trial run of it to see what happens?

After all it sounds like a plain audio amp with a microphone input and instead of the output driving a speaker it drives a SSR

 

Thank you for the vote of confidence, Marshallf3.

The relay circuit is still in the mail at the moment, but when it arrives I'll do your suggested clip-lead setup and post the results.

I do, however, have a few questions stemming from the instructions I found in the online user's manual. Correcting for the manual's broken English, it states:

"When installing, the distance between the sound source and the relay circuit must be as short as possible and a maximum of 30 cm. More over, you must use a low frequency shielded cable. The input signal could be supplied by auxiliary inputs from mixers, tape-decks, etc.. but it must be less than 300 mV at maximum."

This confuses me. Could they actually mean that the electret mic that I'm going to attach to this thing should have a cord less than 30 cm long? Is it possible that this could really matter?
I certainly hope not. I hope that they mean to say that the actual sound source (the human voice or speakers or whatever is actually making the sound) should be close to the mic. If this is the case, it shouldn't be a problem for me because I'll be at a concert with LOUD music which I'm fairly sure that the electret mic will have no problem sensing.

If there is a problem with the circuit being able to pick up the sound from the electret mic that I'm going to attach, I imagine that I could hook up a small amp between the mic and the input. But from the looks of the excerpt above, it seems like I'd have to find an amp that produced an output signal of 300mV or less. This, however, seems minuscule... Am I understanding this correctly?

Also, is it possible that I'll really need to connect a "low frequency shielded cable" to the electret mic for this thing to work? For what? To prevent it from picking up radio waves? Really??
I was hoping to simply use a cheap computer mic for the job, but if it's really possible that 'll need a special wire from the mic to the unit, where would I find a "low-frequency shielded cable"? I've googled this term, but gives me a hodge-podge of all kinds of different crap. Is there a different term that I can use to search for this kind of cable?

Your thoughts are greatly anticipated and appreciated.

 

Just ignore all that for now, but remember that electret mikes need a power supply to operate. Most have a simple coin cell inside.

 

How are you planning on powering this?
How much run time are looking for?

 

I plan on using an 8 D-cell battery pack for each of the 2 LED ribbons.

Here's a link to the kind of battery packs that I've been considering.

My hope is to get about 5 to 6 hours of use out of 8 alkaline batteries before I have to change them.

As I stated earlier, I'm planning on having two identical, yet separate circuits attached to the jumpsuit (one for each LED ribbon.) Both will be controlled by a separate relay circuit (I bought two of the relay circuits that I provided a link to in my previous posts.)

It's my understanding that a D-cell battery has about 12000 mAh. If there were 8 of them wired in series, it would create 12Vdc and 12Ah. Since the LED ribbons are listed at 2A, and the relay circuit that I bought runs on something minuscule (2-60mA), the circuit should last for about 5-6 hours.

Am I mistaken in my calculations here?

If I have to change them once or twice through the night, it's not a big deal. If, for whatever reason, they aren't going to last a practical amount of time, I'd welcome any suggestions about what type of power supply would be best to use.

Thanks.

 

It's my understanding that a D-cell battery has about 12000 mAh. If there were 8 of them wired in series, it would create 12Vdc and 12Ah. Since the LED ribbons are listed at 2A, and the relay circuit that I bought runs on something minuscule (2-60mA), the circuit should last for about 5-6 hours.

I think that's off a little, this is what I found : http://www1.duracell.com/oem/Pdf/new/MN1300_US_CT.pdf

Discharge characteristics chart show a 2 amp load lasting approx 1 hr.

Of course the "off time" will increase the battery life. Where did you locate your battery info?

 

I got my info from the first chart on this Wikipedia page:

http://en.wikipedia.org/wiki/List_of_battery_sizes

But now I see that you're correct. The third chart on the second page of the pdf you provided (the "Amp Hours" vs. "Discharge Current (Amps)" chart), shows that a D-cell alkaline battery can maintain a 2 Amp discharge for slightly more than an hour.

Off time will help extend this, but probably not by much. I'll do this if it ends up being my only reasonably priced (and relatively portable) option, but I'd prefer something that lasted longer. I'd also like to use something that's rechargeable, simply because using this many disposable batteries seems a tad wasteful.

I do have a brand new 12Vdc, 7Ah, Lead Acid Alarm battery that I bought for a different costume last year, but never used. It's a bit heavy, but I know it would work and it would (hopefully) last longer. before I used it, I'd need to try to find a similar chart to the one you posted for the D-cell alkaline.

Do you have any alternative/better ideas for a power supply?

 

I don't have a chart for the 7ah battery, but 7ah is 7 amps for one hour, or 1 amp for 7 hours. That would translate into 2 amps for 3.5 hours, in a perfect world. I think you're on the right track with that battery, but like you said it's heavy. That plus the fact you only have one means once it's dead you lights are too. Turning the sesitivity down will yield less on time thus a longer run time.
Another possible alternitive is borrowing a pair of 12v batteries from a cordless drill and, having both of them charged, maybe get you through the night. You would have to fabricate some sort of connection to the batteries.

 

A 7Ah lead-acid battery supplies 700mA for 10 hours or 350mA for 20 hours. It might supply 7A for 30 minutes or less. Look at its spec's!

Have you consided how much heating the LEDs will make on you?

 

I've been thinking about this all day and I finally decided that if I'm going to have to haul a power supply that's heavy as hell around all night, I might as well go for something that I know will last a reasonably long time, is reusable (& thus rechargeable), and isn't a completely unreliable piece of crap (I've seen plenty of nasty online reviews about the unreliability of this 12v, 7Ah Lead-Acid Radioshack battery that's been sitting in the back of my closet for the last year.)

What do you think about something like this:

http://www.sportsimportsltd.com/odyssey-pc680mj-agm-drycell-battery.html

It's 12Vdc, 17Ah, plus it's deep cycle and weighs only 15 lbs (which isn't much heavier than the 7Ah Radioshack battery that I have right now.) I could put it in a large waist pouch or a small backpack if necessary. It's rechargeable and deep cycle, so it shouldn't crap out on me after just a few hours.

It's a bit pricey, but I live in New Orleans, so I'll be using this costume several times a year (Halloween, Mardi Gras, Jazzfest and even for the Superbowl these days it seems.)

Additionally, Audioguru, you bring up an interesting point about the heat. Fortunately, I'm not too worried about getting too hot. As noted above, most of the time that I plan on wearing this thing will be in the winter. All that I will be wearing with these LED ribbons is a thin, flimsy jumpsuit. The LEDs will actually help keep me warm in the cold weather. Even if I was wearing this thing in the heat of summer though, I probably wouldn't be too worried. I can deal with the heat pretty well. I do plan to make every effort to keep the electronics well insulated so that sweat and/or spilled beer won't be able to reach them and short them out. I made sure to buy the waterproof type of LED ribbons so that I'll minimize the vulnerable surface area. I will be sure to figure out some way to securely insulate the battery and the circuit boards, however.

 

I just found this interesting resource:

http://lib.store.yahoo.net/lib/sports-imports/BatterydrainCalc.html

It calculates the drain on large batteries using the wattage, Ah, and Volts.

At 48 Watts (two LED ribbons) the 12v 17Ah battery that linked to above would go dead within 1.77 hours... The 12v 7Ah Radioshack battery would go dead in about 0.72 hours (just like Audioguru inferred)

I may have to scale back on the number of LEDs for this project to be feasible.

If I used only 1 LED ribbon instead of 2, I would get 3.5 hours of use out of the 12v, 17Ah, 15lbs dry cell battery that I linked to above. This is acceptable in my opinion.

Does anyone see a feasible way for me to power 2 LED ribbons (24 Watts & 2A each) for more than 3.5 hours without resorting to a massively heavy and prohibitively expensive battery?

 

Why are you trying to light up the entire neighbourhood?
If the LEDs use less current then a battery will last longer.

 

Lighting up the entire neighborhood is what it's all about at a costume party concert on Halloween.

That said, your point is taken... I'll probably turn plenty of heads with 300 LEDs rather than 600.

If it needs to be less, I can roll with that too. I'd like to find a good light to power-supply ratio.

 

You will need a very huge and heavy battery to light all thoise LEDs brightly for a few minutes. You will probably see the LEDs dimming as the charge in the battery quickly runs down.