need to ask a question for someone electronically literate

[larryccf]

i've been installing security cameras around the house. These would be considered upper end consumer or home market cameras (Hikvision). Two of them have two way audio capaibility with built in microphones. The issue is i need to add a speaker to be able to communicate with visitors at either the front or side doors. Most of the high end cameras use the exact same 4 port or 4 slot connector with two slots devoted to audio out (GND and "A") and the other two ports for alarm I/O (basically PIR or passive infrared sensors).

The issue is nobody, and i mean no vendor offers an exterior speaker set up that's priced under $480 - i kid not, they all seem to be offered toward the commercial application market. My comprehension of electronics is on the "fred flintstone" level, but i'm somewhat versed in 12V DC electrics, having worked as a mechanic in the 60s and 70s.

First, here's the connector that the majority of cameras offering two way audio use - the two ports on the left are marked "GND" and "A" with the green lead going into the GND slot, The outgoing signal from the "A" side is just that, a signal, no power or amplification, so the speakers will have to have an amplifier built in.
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i started playing around with a laptop speaker set i grabbed off amazon for $10 (i know they're not exterior rated but i'll get to that later), but here's the speaker set



I've added the image so you can see there are two plugs coming off of it, one a USB 2.o cable and the other a 3.5 stereo male jack.

when i plug this set up into my computer, i get a windows menu that opens and allows me to test each side of the speakers, ie R or L independant and when i test, sure enough only one speaker emits any sound, ie the appropriate speaker.

Now here's an image of the volume control on the speaker set

in case this image doesn't expand, here's a link to the to the full size image https://i.imgur.com/TKihgMV.jpg

now, on the right side there two pairs of lead (brown / yellow) with the upper pair marked R+ & R-, and the lower pair marked L+ & L- and each pair goes to a different speaker (the speaker set, as pictured, will split into two separate speakers. On the left hand side there's a Red and Black lead pair that come from the USB plug which i assume are the power source (5V). The two speakers only draw 2 watts total. The other 3 leads (green, yellow & white come from the 3.5mm audio jack, so i assume the green is the common or ground and the yellow & white are R & L speaker signal.

Now, remember when i connected this speaker set to a computer, during the setup or testing, it would play each speaker separately, with no sound emitting from the other speaker ie when i selected L speaker for testing, it would sound thru the L speaker, and not the right, and vice versa.

Removed from the computer, and with the USB connector plugged into a wall wart charger that has a USB port, using that wall wart for a power source, it doesn't matter what wires (green, yellow or white) are plugged into the camera's two ports, i get sound from both speakers. I tried the green in the "GND" slot, and first yellow in the "A" slot, then white in the "A" slot, and i get sound from BOTH speakers. I've swapped those leads around every which combo and same result. I've joined the yellow & white leads together, and get sound from both speakers. But when i tried cutting one speaker off (physically) figuring one speaker gives me all the volume i need at the door, i get NO SOUND. So i had to solder the leads to that speaker back to the volume control thingee (which i assume is the amplifier board.

Am i wrong in assuming the green lead is the common or ground lead? and can someone explain what in the world is going on. With both speakers connected, i get great sound & volume, but it's a little bit of a tight fit getting both speaker cabinets into the old nutone intercom box at the front door - they'll fit, but i was hoping to keep one speaker in reserve if / when the first one fails.

As to weatherproofing, the speaker diaphrams are some sort of polymer so i don't think they'll degrade much from humidity / moisture in the air. I'll probably bed or cover the amplifier board in epoxy to weatherproof it.

any knowledgeable input appreciated

 

[Chicken]

way above my paygrade.... but im sure someone on here. might know the answer to that.... some real bright members on here,,,

i just feed my security system... [ 4 bulldog's ]

 

[burge]

Simply I would go to Radio Shack or circuit city and get a 2 way speaker system ie walky talky type thing. I think it should work

 

[larryccf]

burge, the idea behind a wired intercom system is to be able to not have to change batteries or recharge batteries. Plus the camera is set up for the task - has it's own microphone, and speaker output connections, and all comm is going over the PoE ethernet cable

 

[deluxestogie]

Have you looked through their downloadable documentation? http://vyrox.com/downloads.php

They also have contact info, which might be able to directly answer your questions.

Bob

 

[larryccf]

THANKS, BUT a little leary of downloading an asian sourced doc - before going with hikvision, was looking at the dahua line. I downloaded their configuration tool software to go thru it to see how deciperable it'd be for a "fred flinstone" - before running it, i scanned with my virus / malware (Emsisoft) and it was fine - the instant i ran it, i had never seen emsisoft go into alarm fits the way it did with the dahua asian software. Spent 1.5 hours scanning with every malware, spyware, root file utility that majorgeeks.com recommends - found about six files, two were "DHCP xxxx" or call home files. When i tried the same with the Hikvision USA software config tool, no such event, so that was why i went with Hikvision

i have looked at other mfgr's manuals, and they are all similiarly sparce on info re their audio circuit or requirements. I've talked to hikvision's USA tech dept, which were great for helping me set the first camera up - but they were flat out ignorant of the audio set up, except to point me at 3rd party vendors - you'd think they'd have an accessory speaker kit.

The system is working great (well good volume and clear comm at the speaker), i'm just wondering or worried, if it's putting the same signal to both speakers, have i connected something wrong that might eventually fry the camera's circuit. BUt the camera audio connection does not put out any power, just a signal, so that likelihood is minimal. I'm wondering if the amplification board for the speaker set has some way of recognizing it's a monaural signal coming in and then automatically feeds it to both speakers

btw, i didn't believe the resolution and capability of the current generation cameras - they're up to 4K if you're willing to spend the coin or the application justifies it, but in one demo, they had a car traveling toward the camera - when it passed the 100 yard flag (100 yds distance from the camera) you could stop the video and zoom (digitally) the frame enough to be able to read the license plate. Mine's 2688 x 1520 and i can resolve grass blades or leaves on an azalea bush at 100-110 feet - not perfectly clearly but i can make them out.

 

[larryccf]

burge - there's another reason to stay with the security camera audio - the camera will text msg me with a motion alert on my smartphone, so that where ever i am, hell i could be across the country or at the hardware store, i can hit a button, see what the camera is seeing and talk to them thru the camera's app - the visitor doesn't have to know i'm not home

 

[burge]

The only phone I think that offers that feature is the I phone.

 

[larryccf]

NAH, burge, the camera makers offer the apps for iOS as well as android devices

 

[juan carlos]

you would have to know what is going on inside the the i/c chip amp in the speaker amp board to answer why mono play to all channels, but stereo plays l or r. without having it in front of me with a meter, i can't brain it out well enough to explain it...but it sounds like you are good at tinkering so...
ground is easier to switch than power, so the (-) side of the speaker system is likely the "common" denominator (pun intended) and if you think about (and test) the circuit with this in mind you will likely find the answer, but not find the solution... because you cannot rewire the i/c.
some electronics engineer has assembled the circuit to work as a unit, including the paths of the inputs back through to the source.
just jam it all into the box and if it ain't broke, don't fix it.
i can be a bit of help with waterproofing though...
your local electronic supply store will have a spray called "conformal coating" that will keep the circuit board safe from moisture and small amounts of water.

 

[larryccf]

thanks "i'm good at jamming it all in there". So i gather from your post that it is possible the unit is designed to recognize mono signal and pipe it to both sides

 

[Dominican56]

From the symptom you describe it sounds like your speakers are in series somehow. If you disconnect one, they both go dead.

You need only one audio channel for your camera system I assume. ??

 

[Dominican56]

To clarify your goal:
You want a camera to monitor your front door area (or some other area)
You want audio to broadcast to them? Or do you when to listen to what is at your door?
A speaker system designed for PC output is one way. It outputs sounds in only one direction.

 

[larryccf]

i realize my initial description may have left some clarity out - a number of the new gen IP security cameras offer 2 way audio. The Hikvision model i chose has a built in microphone so i can record video feed + audio feed from the microphone in the camera. But the camera also has an audio out connection - identical connector is even used in a number of different manufacturers' cameras, but nobody shows any accessory speaker set up so that i can "speak" to the visitor. Their software to manage the camera actually has a microphone and speaker icons - the 2 way audio is not full duplex, like our cellphones - only microphone or speaker can operate at any given momemt - so the microphone icon only stays "lit" while i'm pressing it to speak to a visitor. As soon as i release it, the microphone icon goes dark and the speaker (at the front entrance) goes quiet, so the microphone in the camera can go active again. The microphone i speak over is actually in the app on my android phone, so it's using the smartphone's microphone.

Problem i was having was finding a simple affordable speaker to install at the front entrance - when i spoke with Hikvision's tech service rep to see if hikvision offered an accessory speaker setup, he indicated they just refer customers to 3rd party vendors - and the ones he gave me, like i said earlier, the cheapest option was $480.00 USD.

i've had the system working, and the only issue was i was hoping to disconnect the 2nd speaker in the laptop speaker set, to keep in reserve for if/when the first speaker deteriorated but that's not that big a deal. I trimmed the clamping ears off both of the laptop speakers and they fit into the old Nutone intercom station at the front entrance. But at $10.89 shipped for the laptop speaker set, it's not like it's going to break the bank buying a complete replacement set.

The reason using the audio out connection on the camera was important, is that thru the app on my smartphone, i can talk with a visitor while watching what they're doing on my phone, no matter where i am - the camera puts out a "motion" alert thru it's internet connection, to my phone - so the visitor doesn't even know i'm not home. Hell, i could be across the country., or down the street at a neighbors house, it doesn't matter.

But juan carlos' advice was the best - a client came up to visit that is a retired elec engineer & microsoft engineer - and he basically said the same thing as juan carlos - the firmware on the IC chip is probably coded to pipe mono audio signals to both speakers

But all is well now - everything works 5/5

To clarify your goal:
You want a camera to monitor your front door area (or some other area)
You want audio to broadcast to them? Or do you when to listen to what is at your door?
A speaker system designed for PC output is one way. It outputs sounds in only one direction.

 

[larryccf]

this might help communicate what i was describing above - a shot of my phone with the app opened (i've got a 3rd camera on the desk i was getting ready to configure, so excuse the view of my family room ceiling)
- note the headset is lit green - basically it's telling me the microphone at the camera is active. I have the option of closing that microphone by simply tapping that icon