I put a neon tube under my seat of my car that beat to the music, and i like how it looks. Sure beats a random beat that comes with strobes, but anyway...I bought 50 15000mcd blue LEDs to put inside my car, but i would like to have them beat with the music as well. Does anyone have any suggestions on how I could manage this? Thanks alot for the help
may I sugest something like this you will need the U1096B or similar LED driver. Its an easy circuit. But only handles 30 LED's.
SOURCE MATERIAL:InGaN EMITTING COLOUR:BLUE LENS TYPE:WATER CLEAR LUMINOUS INTENSITY-MCD:13000 TYPICAL/15000MAX REVERSE VOLTAGE:5.0 V DC FORWARD VOLTAGE:3.3V TYPICAL DC FORWARD CURRENT:20~30mA VIEWING ANGLE:± 15° LEAD SOLDERING TEMP:260oC for 5 seconds That would be for the LED, and as you know the car will be 14.4 volts.
What do you mean to the beat? To the volume? Or to the amplitude of a lower band? I guess this could become increasingly more complex.
I dont speak german redwolf, thanks for the effort. Either way, if it beats to the volume or to the volume of another band than it would work. I would like to get by without an IC if its possible.
ICs are there to make your life much easier! It saves you a bunch of work and are readily available I love 'em
you do need an IC - a 741 opamp. you will also need a microphone and a transistor (or more then one depending on how many LEDs you are driving). thats it! lemi know if you want the shematic. the way this works: an opamp compares (in comparitor mode, that is) a + signal and a - signal. when the + is greater then the -, it turns its output on. so you have a variable resistor hooked up to the -, and the microphone hooked up to the +. you set the threshhold for the led with the variable resistor. when the volume of the music gets louder then the voltage at the variable resistor, the led turns on. you can use watever filters you want between the microphone and the opamp to filter out trebel, base, ect... but you will probably need a preamp if you do that. you can also hook an opamp right up to a audio signal, just make sure it is within its tollerence range. if you dont want to use chips: thats the equivilent circut... have fun with that
oooooor you can get a set of LM3915 chips, each controls 10 leds. it is a dot/bar display driver with programable current and volume step. the 3914 is the same but with liniar step instead of DB step
i am trying to build a VU meter at the moment with one of them... needs to power 5 blue LEDs of each channel, ordered two ULN2003's which should do it hopefully!
TheShadow, thanks alot for the help, that will help alot! The schemetic would also be a big step in this project, so if you could post that I would appreciate it.
i recently built a boost gauge (for my car) with a the 3914... works great hey, sorry i didnt post before, but i was in school and i didnt have access to any of my books + mags i will proto it out when i get back to school. heres how it works: the "level" is set by the 10k pot. when the voltage at pin 3 exceeds this level, the LED turns on. if it was just 1 led, you could probably do without the transistor, but if i know you guys, you will want high current super bright led arrays so i added the transistor. the whole thing will run off a variety of voltages, just make sure to adust the resistor based on your LED's voltage/current needs EDIT: if your audio is realy low level (like a mic...) you can add a second 10k resistor between the POT and the V+, this will move the range of the pot from +V <-> Gnd to +V/2 <-> Gnd. EDIT 2: here is something intresting... the internal schematic for the LM3914 ( a bargraph chip ). it looks strangely like something else
i just found out that what your trying to build is in essence a one channel color organ. there are 2 ways to do a "sound activated led" 1) comparator mode. this is as in my circuit. the LED will be only on or off. no in between. if you going to be using CCFL's or anything besides LED's, you have to do it this way, because most things don’t like half voltage operation. 2) op amp mode. see the below diagram. the lamps, or LEDs, will be continuously varied between on and off. it is a more complicated circuit, because it needs filtering stuff and a feedback resistor between the input and the output of the opamp. you can peruse this if you want, but i cant help you out here... maybe cpemma or animus can though here is what i found http://www3.telus.net/chemelec/Projects/Color-Organ/Color-Organ-2.jpg
with cpemma's help i have come up with the second revision. PARTS U1: LM358 R3: 10k Pot, 1 turn is fine but 10 turn is best (if your ordering parts anyway) Q1 & Q2 : any 2n2222 or NPN transistor R1 & R2: appropriate LED resistor. use a resistor calculator if you aren’t sure of the value. LED1 & LED2: one or more LED's, hooked up any way you want. just use the right resistors D1 & D2: Not sure if its nessesary... lower voltage drop the better J1: optional 1/8" stereo jack NOTES this one does separate L and R LEDs. if you only want 1 LED, you can use a "CA3140", with the same pinout as version 1. the reason i changed the chip is because the 741 doesn’t have the resolution to see some audio signals, this one should work over a wider range of input types (line, speaker, headphone, mic, ect...) a third version is on the way with adjustable gain which i apparently need
Cool project. Anyone ever try a PIC version of a light organ? It seems discrete components is a better way of doing it, but I'm curious. I have a lighting system that's a pic pwm driving three rgb led boxes. (18 rgb leds each). I'd like some sort of sound input. I was thinking maybe Red = left vol, Blue = Right vol, Green would be some sort of function of the two. Maybe peak. The other thing that boogles my noob mind is sound is AC correct? I could see using a diode and basically loosing half the input, but I have no idea how you'd convert it to pulsing dc.
the problem with using a PIC or other MCU is you need to sample voltage, i.e. you need A/D. theoretically, you could hook this circuit up to your PIC and count input pulses per loop, or any other way you could think of. but for a classic light organ, especial one with PWM capabilities, needs a fast sampling A/D, which, IMHO, is over complicating it. remember the KISS principle (Keep It Simple Stupid) DSP is a not so fun thing to do... a mate of mine has been for the last 4 years trying to DSP a radio system, there’s a lot of , so when you don’t HAVE to do it, don’t. Maybe that’s just me sound isnt AC or DC. sound is a wave carried by air. when you use a microphone to convert that wave to an electrical signal, it is usually represented by AC. this means that the signal has a + component and a - component, relative to a common ground. if you take a diode between the signal line and ground, the - half of the AC wave greater then .7v will short to ground, leaving only the + half. this signal is pulsing DC, but only 1/2 of the signal. to get both half’s, and effectively double your average voltage, you need a bridge rectifier. this will output + for both half’s of an AC, but you will loose the first 1.4v of the signal. when dealing with low level audio, this is just not acceptable, as the signal often does not exceeds 1 volt. EDIT: maybe an electrolytic capacitor can get rid of the negative component without the voltage drop. Someone double check me on that though
I guess I should have said "when sound is converted to an electrical signal via a transducer" Not a bad idea about counting pulses. I'm just looking for some reaction. Doesn't have to be perfect. Can't you add ac to dc and end up with pulsing dc? I would think there would be some way of biasing the voltage a bit. Maybe I'll just use discolitez (I'm working on the car pc now)
