EEVblog #182 - Rode Videomic Shotgun Microphone Hack

Dave does a quick hack on his Rode Videomic so he can actually see the battery LED when he's in front of the camera.

[EEVblog]

@EEVblog Actually, I just checked the mic spec, and it's 5mA consumption. So almost all of that battery life is pissed away in the LED. So I think I'll redo this for series operation and drop the current to boot.

[EEVblog]

@RicardoATBarbosa Generally, yes. But in this case there is not really enough voltage from the meter in ohms mode to conduct the LED in series, so it measure spot on. And I would have expect an E12 or E24 value resistor and got it spot on, so you can be fairly confident it's correct.

[EEVblog]

@Bushougoma Huh?
I meant not directly in parallel with the other LED (without dropper) as many beginners make the mistake of doing. Sorry, I have not watched the video back, did I actually say the wrong thing?
If two LED's are in series they have the same current, one LED can't "hog it".

[EEVblog]

@CampKohler I thought briefly about that, but too much trouble and overkill. I don't really have any dynamic range or clipping problems, so a level meter is nice, but not of huge help to me. I have my gains set and I rarely touch them. Plus it's messy having an extra box.

[LaraSchilling]

Rode are amazing. I'd kill to work for them :P
The slits around the sides of the actual tube, they are phase ports. The mic's range would be cardioid (meaning it picks up in a heart like range around the front of the first (pfffft)* filter). Any noise that gets picked up around the sides of the phase ports are chucked out of phase (by the preamp, being balanced) and only signal going in through the front is picked up.
*The first filter is used to mellow out the harsh sounds of p's & f's

[EEVblog]

@coolffrost6 Don't know, you'll have to ask the owner. Australian owned and run company.

[EEVblog]

@tonyrueb I didn't have any fibre optic cable. I have plenty of LEDs.

[EEVblog]

@Wolfcritic64 Maybe. But I didn't have any. Got plenty of LED's though!

[EEVblog]

@TrueBlueAustralian There is no model number, it's the "Videomic"

[EEVblog]

@tvolala1976 The camera moves all the time, and I still ant to see the rear LED. A mirror is not a practical solution.

[EEVblog]

@kekejojo1212 Interesting idea, and might be possible, but not guaranteed to work like the LED. That that I have any suitable thick fiber optic cable. I think I'll redo this to put the LED in series to lower the consumption. At first I didn't care it was 2mA extra, didn't seem majorly significant. But now I know most of the product current is wasted in the LED.

[EEVblog]

@ZitroOgu Yes, could have done that. In fact I don't know why I didn't... Must have just had it stuck in my mind that there wouldn't be enough drop to allow that before I measured it.

[ParaScubaSailor]

I suspect the LED IS the major power consumption of the whole circuit, so doubling that might not be a good idea...
I would have replaced the drop resistor with a different drop resistor and the new LED, so in series with the existing one. The new resistor is calculated to have the same current (R = ((4.5v + VdropLED1) - (VdropLED1 + VdropLED2)) / 4.5mA, probably in the region of 680 Ohm).
Wiring is also easier: the resistor + new LED as a dipole replaces the surface mount resistor.

[EEVblog]

@ivaneduardo747 No, photo cameras have too many limitations when it comes to recording video. Even a $200 camcorder will be more usable for video than a $2000 DSLR

[Polite_Cat]

@EEVblog neat! i love it! i had an idea..could you simply glue a little piece of fiber optic wire to that little plastic piece over the LEDs? then, drill a hole to the outside and done! no extra power consumed and both leds work!

would it be visible enough? i dunno.. if you had thicker fiber optic wire maybe?

you should totally email this to them! i think they'll love it.

[petersage]

3:20 Looks fairly in proportion to me; maybe a little on the small side.

On a more practical design note, shotgun mics weren't typically designed with video bloggers in mind; they are often used in situations where you *wouldn't* want a tattle light.

[obiwanjacobi]

Indoors you can leave the "foam condom" off. You'll get a brighter sound.

[tooby]

Even better: Connect the mic output to a second hand analog scope and you can SEE the sound!

[thumasta]

you should contact the microphone company and give them a link to this video.. maybe they'll give you some design work.. lol

[FortressofSound]

I have the VIdeo Mic Pro and found your vid trying to research if it's possible to modify it to have a feature only the newer Video Mic Pro+ has. The newer model has some sort of relay that only powers the mic when the camera is switched on. When the camera is switched off the mic also switches off. It must be getting a signal from the TRS mic jack and telling the mic to enable the battery power. I'm wondering if there's some way to mod my original Video Mic Pro, which has an analog power switch, to have this "auto power" feature. Do you have any thoughts on this? Thank you!