Hey folks. Please help me with this question I have.

[waldoctg]

Hi Folks,

How are all of you? I'm new on this forum and I am glad to be here!

Anyways, I need some help on a little project I am trying to achieve... I've been working on it for sometime, but unfortunately I am not very knowledgeable when it comes to circuits and need some help. It's kind of complex, so please bare with me. If anything is unclear, please ask me to explain.

Okay, here is what I want to do. I want to connect a small microphone, two LED strips, a laser pointer module, a battery pack, and an "on/off" switch all to a handheld device which would allow me to harness my digital camera to it. This would give my pictures/videos better sound, lighting, and a light that will allow me to point at stuff ( the laser pointer). The battery pack would power it separately from the camera, and finally the power switch would all me to (obviously) turn the device on and off.

Now, for further detail:

-The microphone would be one of those small ones that can be powered off of cameras. It'd be similar to the cheap ones you can buy for your iPod Touch. If you know of a nicer mic that would draw a little more power and thus need to be connected to the battery pack, but be better sound, please inform me.

-The LED strips would need to be, at most, 8 inches long, and allow me to provide light from above and below the camera. In other words, I'd basically have two different 8 inch long spaces on the device for the LED strips. It doesn't HAVE to be a strip, but could be two modules of LEDs - say, two 3 inch modules. I say this part about the modules as I'm looking for good lighting, but I want to be able to have it draw the least amount of power possible as I am using batteries to power it and am open to whatever configuration will suit this the best.

-The laser pointer module (this will allow me to point at stuff as I am recording it and talking about it), would again need to draw a little power as I would run this off the battery. I would probably use a 5mW red laser module, but I am totally open to any ideas if you know of a different laser that would suit this device better.

-The battery pack would need to be as light as possible. I purchased a 4 AA battery holder pack, which seems like it will work, BUT I was wondering if there would be a better way to power this (smaller, lighter, and more powerful, all while using popular type batteries so that way I can still find batteries fairly easy - i.e. 9v, AAA, etc...). Maybe have two separate power packs? Just an idea...

-The momentary switches would be for the LED switches and the laser module. I would want one for each so they could be controlled separately.

Two last notes: I would like each of these modules (the LED strips, the laser module, the battery packs, and the momentary switches) to be able to be connected to the main device using connectors. This would allow me to keep all the wiring inside the device and not have to re-wire anything IF one of the modules needed replacing (say, the momentary switch for the laser module died), but would allow me to simply detach the defective one, and attach the new one onto the device. Also, I don't know what size of resistors or wiring that would suit this the best. If you could include that, I'd greatly appreciate it.

If someone could help me, I'd appreciate it so much. I've been trying to search this forum for this, but can't find a similar layout... I don't really know how to calculate the correct amount of power and all that as, again, I am not very knowledgeable in this...

Again, thank you so much.

Waldoctg

[adafruit_support_mike]

If I'm reading correctly, you want a device that will supply more light and take in better sound for a videocamera, yes?

If so, you're looking at a couple areas where you need to do some more research so you can zero in on a description of exactly what you want.. 'cause the parts you described probably won't produce the results you want.

For lighting, you need to know how much light you want to throw, and how far you want to throw it. There are a lot of units for measuring light are many and confusing, but the two that stand out most are the 'lumen' (roughly, how much light the device puts out) and the 'candela' (how much light hits the surface of an object). Unfortunately, most people think of light bulbs in terms of the power they consume. For a rough translation, a 60W incandescent bulb produces about 750 lumens. A surface 1m away from a 60W bulb sees about 60 candelas of illumination.

Light spreads out according to the inverse-square law, so moving twice as far away means you get a quarter as much light per unit of area. At 2m, the illumination from a 750 lumen lamp is only about 15 candelas.

LEDs produce light more efficently than incandescents, but they still have limits. A Cree XLamp MX-6S 1.2 watt white LED produces about 125 lumens, but only across a 120-degree angle. A little solid geometry says that a 120 degree angle lights about 1/3 of the surrounding sphere, so the LED only puts out about 1/6th the light, but concentrates it into 1/3 the area. As a result, a surface 1m away from the LED will see about 30 candelas of illumination.

So.. it takes two LEDs, each consuming 1.2W of power, to produce the same illumination as a single 60W incandescent lamp. Thing is, LEDs in question want 20v of supply voltage. You might be able to shave the voltage requirements by using a larger number of smaller LEDs, but you're still looking at somewhere around 2-1/2 watts of power to get lighting that equals a single 60W incandescent. That would be about 16 3v white LEDs running at 50mA each, and a AA battery pack supplying that would last maybe an hour.

For audio, especially regarding microphones, the laws of physics pretty much lead to 'bigger is better'. Electret microphones (the kind used in cell phones) are good at picking up sounds an inch or two away. Sound also obeys the inverse square law though, so electrets get progressively less good the farther away the source gets.

Microphone design is a complicated subject, but if you want to record sound out in front of you where the camera is pointing, you pretty much want what's called a 'shotgun' mic.. the area it listens to is vaguely like the beam of a flashlight: long, narrow, and sticking straight out in front. Once you find one of those that matches the conditions where you want to use it, you might want what's called a 'preampifier'.. a circuit that boosts the signal from the microphone to whatever level your video camera wants as input. For quick-and-dirty circuit design, an LM386 audio amplifier chip will probably do the job, though you may also want to use a good op amp.

Your starting point is to decide how you want to use the rig though.. how far away will your subject be, and what kind of surrounding conditions will be normal? You'll also need to know what kind of auxiliary input your camera wants, so you can build an audio circuit that produces the right signals.