Hi, I'd like to make my own wireless Lapel Lavalier system.
Like I said in my previous video, I think in my opinion it's the best way for quality audio recording,
because the microphone is closest to the source and picks up the voice as loud as possible
Which reduces noise and echo. Also you can walk far away from the camera.
(Seductively) It's as if I'm constantly
whispering in your ears...
Isn't that what you want?
( ͡° ͜ʖ ͡°)
A wireless lavalier has a transmitter
That's clipped to my pants or whatever down there, and a receiver that sits at the camera and plugs into the camera's audio input.
But how do I make my wireless link?
Maybe a link with two Bluetooth modules?
Or maybe two Wi-Fi modules so I can link multiple transmitters.
Or maybe I come up with my own mystery wireless link!
Nyeh.
Let me see if someone will sponsor a free sample.
The good systems are usually expensive.
There are a lot of companies out there that make this cheap though,
But I don't want to be like:
(Horrible bass boosted mic) Wow! Look at this product! So quality, much sound!
So I might as well aim high.
For example, I know Røde Microphones makes pretty good products.
Let's email them.
'ello, love!
In the meantime
I'm a lazy bum and like simple solutions, so here's my transmitter and receiver system
This is an FM transmitter, which I picked up for around 20 dollars, and there are many models of this out there
What it does is that you plug it to your phone for example,
And it transmits your phone music to your car's FM stereo.
It is useful if you're driving your granddad's car which all it has is an FM radio
And this is my daughter's FM radio
Which is my receiver. Let's try it out.
On the FM transmitter, you have the option of selecting many different frequency bands
So you can pick one that's empty in your area for best audio quality
And then on your receiver you tuned to that frequency.
Here we are. It has a bit of static noise, which is low, see?
(Static from toy radio)
Let's play something on it
(3D Printers song)
Eh, the sound is not very good because the speaker is a small.
Also I can see that the range could be an issue because both these things have short antennas
Still no response
Come on, man, I'm too cheap to buy a microphone. :c
At mid-range FM frequency of about 100 MHz the wavelength is around 3 meters
So a proper monopole antenna length is half that or one and a half meters
Which is a bit too long.
So a quarter wavelength of 75 cm or two and a half feet sounds more adequate.
In fact instead of this garbage
I can use my cellphone's FM radio. (TUNE INTO 88.1 IN VANCOUVER)
The antenna is the headset cable, see?
(Alternating radio sound and static)
And I can make it as long as my pe- UHHH-upper antenna length.
the app also shows me where the channels are so I can pick a quiet band like this one and then tune the
transmitter frequency to the same. See?
It's pretty quiet, too
Now I just plug this into my camera audio input. Let's see what kind of range we get
Well I walked pretty far like 10 meters before I ran out of space
Let's see if I can add some antenna links to these to make the range even longer
There we are
There we go
But now I kind of ruined the battery contacts
Where the hell is an antenna?
Well, if I'm not wrong like many of them do they are using this cable as the antenna so what we really needed to do
Was just to increase the length of this cable. It was kind of a waste of effort
No, well, let's put it back together, and hope it it still works. Okay, let's check it before I completely close it
Lights up
There. I think it's okay
Good
Oh well, let's get the audio going. I'm gonna connect my cheap microphone to the transmitter
And for that I'm gonna solder two female audio jacks back-to-back
But I really thing they should call the female ones Janet. That's it from now on
This is an audio jack and that is an audio janet. Okay, let's transmit
Hello
Hello, hello
lloooo!!!!
Ah f**k. This is a condenser microphone. Unlike a traditional dynamic microphones
which have coil and magnet, this doesn't generate its own voltage
It's like a variable capacitor that changes by audio waves,
so it needs to be powered and biased
So basically they put a resistor in series with the microphone between the supply rails,
and the DC voltage here has to be set in the middle of the supply voltage for maximum signal output,
and also that signal level has a direct relation to the supply voltage
Okay, I have the circuit on the breadboard. Let's power it up
Oh s**t. I created a light bulb
Obviously, there's a wrong connection. F**k
Come on, Røde. Put me out of my misery
Okay back in business. See? hello hello hello
It seems like around normal distance, the signal is not very large, it's around 100 millivolt peak-to-peak
Okay, I connected the microphone circuit through a capacitor to the FM transmitter,
and my phone is on the maximum volume. Let's hear it
Hello, hello hello. Hello
The volume is not too loud
I think I need to add an amplifier to the circuit
This is the circuit I designed. Basically the microphone signal goes through a buffer
and then a gain stage that has a variable gain adjustable by this potentiometer,
and the output goes through a capacitor to the right and left inputs of the FM transmitter,
which also needs a ground connection. You can find more details on my website.
I put the circuit on the breadboard. Let's do a quick smoke test
S**t. F**k
What's up with my circuits and all this smoke?
RIP
A resistor makes a light bulb and a capacitor makes an explosion when connected wrong
No response.
Okay, let's not give up. See, I fixed it. Hello. Hello. Now the signal can be over 2 volt peak-to-peak
And now of course the transmitter test. See?
You echo hello?
1 1 3 4 4
See? Awesome. Now, all I need to do is to take on this circuit and put it on a prototype board
Life is a piece of s**t
There we go. Input and output, and volume control
This thing can run on 3 volt, which my FM transmitter already has,
so I'm going to melt the hole into the body of the FM transmitter,
and run the power wires through it
Solder one of them to the battery negative, and the other one after the powers to each of the transmitters
so it can turn on and off with the same switch
Now we just plug in the microphone and the FM transmitter, and it's ready to go
Let's connect the phone to the camera
(Late audio) Okay. Listen to the noise.
And here's how I sound.
Isn't it just a genius design?
(ノಠ益ಠ)ノ彡┻━┻
There is something called latency which I didn't consider.
The sound itself takes around three milliseconds per meter to get to the microphone,
and then a few more milliseconds to go through the electronics, get modulated, go to the receiver,
demodulated, decoded, and go through the app to the output,
and the whole thing together in my case takes 300 milliseconds.
It's like talking across a football field
Hmmm?
YESSS!!!
This video is sponsored by Røde Microphones.
The builders of the best microphones in universe. (Laughing)
They are sending me a shotgun microphone, and a wireless lavalier. (Laughing)
I guess I'll check them in the next video.
Well, it's such a shame. If it wasn't for the latency, this thing was decent.
Now you might say you could align audio and video in post process. Let's try it.
Here, I'm using my system and align the audio.
I would say it sounds well. In fact, it makes sure that the right audio and video
are always recorded together compared to recording audio separately.
You just have to shift the audio in post process. So it's not a total loss.
The range you get with this thing is close to 10 meters, which is pretty decent for most applications
Something I learned, aligning the audio and video was that our brain is used to delay to some extent.
Like I said, it takes 3 milliseconds per meter for the sound to travel through air.
So if you are talking to someone 5 meters away, it takes 15 milliseconds.
Our brain has learned to expect delay based on distance.
For example, right now, audio is 60 milliseconds delayed from the video, but it doesn't sound too bad.
And now the audio is 30 milliseconds earlier
(Mind blown)