I would like to use car headlights as bass indicators. It should be necessary to use low-frequency pass filter and some kind of a driver strong enough to light up 2x50W headlights.
sounds cool, i have no idea how to do it, but it would be massively illegal to be driving with it on. you could use it for shows and such witch would be cool. any way you could get your hands on the sound reactive portion of the units meant for under glow and just mod it to turn on headlights instead of tubes of neon?
A high power transistor/mosfet switch setup could be made, setup to drive from low/active filter or high/passive filter audio input. I think under body & in car neons would look better, and are readily available. Both options are a little overly ricey btw
LOL it thought he was talking about putting them up in his rig! Heh, imagine the brightness of 2 car headlamps in a computer. Sorry if I was not any help, I just thought it was funny.
I was thinking the same thing actually. I've seen it done before, I'm not sure if it was a commercial kit or what.
mine do that already, but only b/c i'm drawing too much current from my alternator probably a lpf into a relay would work best.
If it's rated for say, 100,000 clicks, then with 100bpm music, @ say 3 minutes each = 300 clicks per song = 333 songs until you have to buy new relays. If you play one song a day or around 7 songs each saturday night, only when in carparks etc with the headlights flashing, then this setup will last a year. If the relay is rated at 10,000 clicks, then we're looking at about a month life for the two relays - you'd want one relay each per globe, as sharing one relay will probably half the life of the relays. You'll probably get sick of it soon so it kindof sounds like a plan. The constant on & off will shorten the car headlights considerably, so keep two spare globes in your glovebox. You'd need a switch to decide when the headlights are being controlled by the relay or not, and a decent diode on each of the relays. I'd rather use transistors cos i prefer not to use them instead of mechanical relays, and with transistors, the lights can turn on & off a little more slowly - still at the beat of the music but more gradually, with the beat of the music so it would look better, and this will reduce the wear on the globe filaments, compared to abrupt off & on use.
well, you are switching from low power to high power, so i'm not sure a transistor would be the right way to go. an opto isolator might be a good choice. How do you want this thing to work? for example, if you get a 50Hz signal for 5 seconds, do you want it the lights to stay on for all 5 seconds? Do you want them to pulse? If it goes on do you want it to fade on or just go from off to on? If it goes off, do you want it to fade out there as well? and yes, this will considerably lessen the life of your headlights. but at $5 (maybe?) for a set of 2, who cares? how much current does a headlight draw?
a 2x50W amplifier with a low pass filter? even a POS one would be fine for the lights... and probably as cheap as buying relays and sockets or making your own. http://cgi.ebay.com/Sony-can-amplif...ryZ39739QQssPageNameZWDVWQQrdZ1QQcmdZViewItem little underpowered, but nice size, plenty of other cheap stuff on Ebay http://www.amazon.com/Audiovox-AXT-...2?ie=UTF8&s=electronics&qid=1209599376&sr=8-2
You could use an optoisolator, definitely a safer option Light bulbs & relays don't cost that much i guess, i was just letting him know + there's my anti-relay bias A 50w 12v globe will draw 4.2a, and the off/on of 4.2a will eat away at the relay switch contacts, which is why i suggest using one big relay per light, like 20a or more, to lessen the resulting wear from the arcing. You can't use a 50w or 25w audio amp for 12v globes, cos those amps will output more than 12v, further shortening the life of the globes, and the globes will draw more power from the amp than the respective 50w or 25w, since the resistance of the globes is only about 2.85 ohm, which will drastically shorten the life of the amp aswell. You could wire the lamps in series, which would solve the problem, just means the globes won't run at full brightness, which is fine i guess. You'd have to have this circuit switched of course to return the lights to normal parrallel wiring for driving of course. There is a better solution i think, and that is to drive the park globes instead of the headlights! That way you won't have this blinding light flashing on & off, your car's battery will last alot longer for carpark or beach parties, it's cheaper to build and maintain, and if you fit neons to your car, the resulting light will be more in line with the lighting provided from the neons. You could even use colored globes instead of white! to match any neon lighting or the color of your car, etc... Another option is to hook it up so that the parker lights, brake lights, and interior lights flash to the beat of the music - very do able, and the combined wattage of all these globes is probably less than 50w aswell, compared to 2 x 50w for the headlights. The whole lot can be switched aswell, so everything returns to normal when you drive - you'd definitely want an very noticeable led switch on your dash cos the last thing you want is to have it on by accident while you were driving
I can't see relays working. The contacts would get obliterated in no time - 4.2A through a gradually increasing surface resistance. Welding the contacts might not be out of the question either IMO the circuit would be a low pass filter driving the gate of a suitably meaty N-Channel MOSFET. By suitably meaty, I mean probably TO-220/TO-247 capable of 20A with a big lump of metal bolted to it. Voltage is presumably not a problem - car lamps are 12V, so you can run everything from the same supply. The low pass filter could just be an op amp or a small signal transistor and a few passive components, or you can get more technical and do higher order filters which reject other frequencies better (first-order sallen-key filters like this high-pass one can be daisy chained to give much steeper roll-off - one quad-opamp chip gets you fourth order: 48dB/octave). If you want to run it on AC, you can use a thing called a Triac in place of the MOSFET, but you have to tune your filters a bit more as the Triac is more sensitive (essentially on/off). NB this wont work with Arc Discharge (HID) lamps! Don't try, you might end up killing something.
I_DSS on mosfets, the Zero Gate Voltage Drain Current. Plus car environments are noisy as hell. I guess it really just matters where you put your mechanical "on/off" switch.
I want the lights to stay on for all five seconds. I dont want them to pulse during that time. Fade in and fade out should be recommended. I really dont mind the number of relays. Maybe the relays are not good option? Parker lights are 2x10W + 4x4W, interior lights are 3 x 4W, the sum is 48W. So, do you think that the power of headlights is the only problem? If its so, I could use the lights mentioned above.
Yeah, using high powered relays is possible, but i've described why they are not a good option. I don't think it will be that hard to hook up some powerfull mosfets to power all the "small" lights (48w), and be driven from any of the speaker signals, using a low pass filter and a voltage divider, if required, to get the signal smaller. I'm not sure what you mean by when you say you want the lights to stay on when they are getting a 50hz signal? 50hz is bass btw, many factory car speakers, say 6", can't go lower than about this. Good small subs, say 6x9's or 8" can go down to around 30hz, good bigger subs can go down to around 20hz or even a touch lower. Anyway, i would have thought you'd want the lights to pulse/flash to the music/beat, like they do on a v/u or eq display? They wouldn't be a strobe style flash, as the filament globes can't dim that quick. It shouldn't be too hard to incorparate some sort of capacitor timing circuit, so that the light fade can be further slowed down, even with a variable resistor so that this can be adjusted. You can't slow them down too much though, otherwise the lights would just turn on, and stay on when there is bass, and only fade off when the bass has stopped or the song is finished. So they wouldn't be bass indicators/dancing lights. Maybe even hook up the indicators aswell? Or maybe i'm goin overboard with the colors now? You know it is posible, to have the output lines from the mosfets, with a switch on each output wire, so that you can easily select which lights are being triggered my the music. And again, most important is the off switch for the dancing lights to be an led switch, or at least have an led for status in a very visible location on the dash! This whole thing, mofets, filters, dividers, etc, wouldn't be that big, including it's heatsink. It would probably be a similar size to a med sized car amplifier. A dead med sized car amp would actually be a nice looking, appropriate case and a good heatsink to use aswell!
right, he wants them as bass indicators. the 50Hz was an example. if, for instance, you are listening to a bass-tuning CD, they step thru the frequencies and leave them on for like 10 seconds. He wants his lights to start to fade on at t=0 and fade off at t=10. depending on the music, they will. most music is a thump-thump-thump, not a continous 50hz signal. so they will blink. thats a pretty sweet idea! You could always heatsink it to the car chassis as well. I'll draw up a schematic, any idea what you want the corner (cut-off) frequency of the filter to be?
Ahh, i didn't know you guys were talking about a constant 50hz signal Another good feature is to have another variable resistor to set the gain or input input voltage, so that we can decide how bright the lights will go. And with the cut off frequency, how about a rotary switch to select different cap sizes, so we can choose a few different roll-off frequencies, such as say around 40hz, 60hz & 80hz, for example. If you use a pre built active filter which can be had pretty cheap, then it would probably have a little switch to select a few roll-off frequencies, probably a wider range like 50, 80 & 120 or something like that.
