Subscriber Discussion

Switching Off Camera Mic, Preferably By Physical Wall Switch?

DC
Dwayne Cormier
Nov 13, 2018

I have a law enforcement client that has a need to turn off/on a mic. This is preferred to be done by a physical wall switch. Easy enough to have a switch to turn off low voltage power to the mic. However the current system they have is NVR with only one external input (they need two) and cannot introduce the mic into the IP camera they have. The camera vendor has no other options but via software which is not preferred by my client. Any ideas? My option is to install a second system with cameras that have a mic lead on the camera and power separately.

UM
Undisclosed Manufacturer #1
Nov 13, 2018

Axis has the P8221, which is a network audio device.  Not sure if/how it would work with your current system.

 

I typically will have a wall switch interupt the mic signal or power.  I always use an external mic for best quality for police interview rooms, etc.  If the camera they selected doesn't support an external mic, you should change out the camera if audio recording with a switch is required.

A small NVR is so inexpensive that it may be easier to just buy another NVR and camera for this application.

The final option, is if there is a software way to do it...  Get the API command to enable/disable the mic, or enable/disable the audio from the stream, and connect the wall switch to a single board PC, such as a raspberry PI.  When the switch is in one state it sends a CGI command to enable.  When in the other state send the other command.  

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DC
Dwayne Cormier
Nov 13, 2018

That is the problem. There is no compatible camera for this system to switch out with. My best option to them was use the NVR software and install the cameras with built in mic's or I install a second two camera set up.

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Avatar
Fabian Muyawa
Nov 13, 2018
LONTECH SYSTEMS • IPVMU Certified

I suggest you wire the two switches in series and connect the ends to the input so that you can switch on/off at any switch. This means that when either of the switch is off then the mic is off, again when all the switches are off, the mic is off and only when all the switches are on then the mic will be on

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U
Undisclosed #2
Nov 13, 2018
IPVMU Certified

Are you saying that you want to put a physical switch on a camera’s built-in mic? On a camera that has no I/O or other xtra ports?

DC
Dwayne Cormier
Nov 13, 2018

No not on the built in mic. Current camera does not have a built in mic and does not have a external connection for one either. What is needed is a way to switch off the mic physically. This would be by means of turning off/on power to the mic with a toggle switch.

U
Undisclosed #2
Nov 14, 2018
IPVMU Certified

This would be by means of turning off/on power to the mic with a toggle switch.

Right, so why not do that?

Because you don’t have a free input?

Are you trying to toggle between two inputs to manage this or?

DC
Dwayne Cormier
Nov 14, 2018

Right, i only have one input to the DVR need two. I gave a break down on my response to Kyle. I hope it cleared up the scenario I have better.

RS
Robert Shih
Nov 13, 2018
IPVM

So basically, if you have an IP camera with the audio inputs, just add a switch into the circuit for the microphone's power source. I don't think it should be any more complicated than that.

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DC
Dwayne Cormier
Nov 14, 2018

setting up a mic to a switch was not the issue. It is the set up im facing with very limited options. See my reply to Kyle.

Avatar
Kyle Folger
Nov 14, 2018
IPVMU Certified

I tried reading all the comments and I'm still rather confused. When you say the NVR has one external input, is this a microphone input or a contact closure input? How many microphones are there in total currently? How are they powered currently? Do you have a model of microphone since I seem to gather they are external microphones. What model are the cameras and NVR? I'm just trying to understand and get a clearer idea so I can provide a more informed response.

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DC
Dwayne Cormier
Nov 14, 2018

Sorry let me try to clarify. Tried to pack all the info and keep it short.

Client has an NVR IP camera system. The NVR only has one external input for mic and they need two separate mic's. With this they need the ability to turn off the mic (not the camera) when a lawyer is talking with his client in private. To do this with built in mic cameras and via software is not a solution that fits their scenarios. (time restraints, not technical, etc)

I already planned to wire the power separate to the mic and have it go through a switch. Each mic has its own switch in a convenient spot and this would resolve what they need. BUT...the system they bought (after talking with tech support of equipment) does not have a camera with an external mic connection so only option with this set up is the one external mic to control or use the software to toggle mic off/on.

So my question was if anyone has similar issue and found a work around. My only other option is installing a second system for just those two cameras and mics, as I could not find an IP camera with external mic connection.

Hope that cleared up my scenario.

Thanks

Avatar
Brian Karas
Nov 14, 2018
Pelican Zero

Sorry, I still don't get it.

Why don't you just install the switch on the wire carrying the audio signal from the mic(s)? Interrupt the electrical path of the audio signal and you will have muted the mic. This should work independent of what camera, NVR, software, etc. you use as you are disconnecting the microphones connection to the rest of the system.

 

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Avatar
Kyle Folger
Nov 14, 2018
IPVMU Certified

Thanks for the reply. So to me it sounds like the issue isn’t switching the mic on and off but the fact you only have one analog external microphone input. Is this device not ONVIF compatible and that is why you said the manufacturer doesn’t offer a camera with an external mic connection. If that is the case, how bad is this system? Even Dahua has cameras with external mic connections. I’ve used them with Crown PZM mics before and Spectrum VMS. 

Most decent analog DVRs had 4 audio inputs. I have done larger rooms with an external mixer from ETS and the ETS power supply that converts the balanaced mic line to unbalanced audio. This was for a police training acadamy where they wanted instructors recorded as well as questions asked.

Assuming these are different rooms and they are used at the same time I would go with a separate system and use external mics into the cameras and have the wall switch on the analog switch so it’s switched before ever reaching the camera.

UM
Undisclosed Manufacturer #1
Nov 14, 2018

Two options.  

 

Option 1.  Install another NVR for these 2 cameras (You actually only need the NVR for 1 camera, as the current NVR does have 1 external audio input)

 

Option 2.  Change the camera to one that has an external mic input.

Personally, I would change the camera, as a camera typically is lower cost than an NVR with a hard drive.  IMHO, most "full size, full-featured" professional IP cameras have an external mic/line input on the camera.  Smaller size, compact, or low-cost cameras often do not.

If this is for a police interview room, I personally would recommend that the audio input is run into the camera, so that the "evidence" isn't being altered.  The camera is streaming out video + audio and the NVR is simply recording it.

With an NVR with a separate audio input, you have no idea if it is recording a separate audio track or re-encoding the video to include the audio, or whatnot.  I would be concerned that if there was a big legal case, could they try to pick it apart that the video has been altered or how do they know the audio is legit to the video...

Just my thoughts that the audio should stay at the edge with the video.

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MD
Matthew Del Salto
Nov 14, 2018
Hudson Security
Why not get some sort of button wired to the network that sends an http event to trigger the software to turn the mic on/off? Probably a bit too high tech for something that can likely be done physically.
U
Undisclosed #3
Nov 14, 2018

Is there some way we could work IFTTT into that mix?

MD
Matthew Del Salto
Nov 14, 2018
Hudson Security

Yes, technically it is a webhook. You need to look into the NVR api to see if it is possible to turn mic on/off with the api.

Avatar
Clint Hays
Nov 14, 2018

After looking through the comments and confusion I think you would be benefited by listing the hardware brand/models you are working with since you are asking for product dependent help.

 

If you are asking for API's and commands you need to say what you are working with.

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DC
Dwayne Cormier
Nov 14, 2018

Yes Clint correct I should have included that. They bought GW Security equipment with a GW3216E DVR, GW-5037IP camera.

Matt, I wanted to avoid getting to techie and complicated to turn mic off/on

Not top shelf but more of a DIY save money set up. I have not checked camera compatibility but for two locations on this set up and I prefer to have audio on same line as camera looks like best choice is to install a separate system.

This is one of those I wish the client reached out about specific needs before they decided to save money and internet shop and self install.

JH
Jay Hobdy
Nov 15, 2018
IPVMU Certified

Just curious, is this a good client? How much time has been wasted on trying to make this work? Are you billing for it?

 

I would have said you need 2 ONVIF cameras with a separate microphone input. If the NVR won't work with them, I would quote them a new NVR. Not your fault they did not consult you. 

 

My dog's vet told my wife to stop using Dr. Google....

DC
Dwayne Cormier
Nov 20, 2018

yes jay good client. small commimity local sheriff office so some things we dont bill and offer solution options as free consulting. 

but yes i agree with your thoughts

Avatar
Ron Ayotte
Nov 20, 2018
IPVMU Certified

Not sure if you want to use this solution - but it will give you an idea of a system designed around this need for law enforcement.  

https://www.casecracker.com/

 

DC
Dwayne Cormier
Nov 20, 2018

nice. i will certainly look at that. thanks for the input

U
Undisclosed #4
Nov 20, 2018

Use voice activated mic, it's 2018.

DC
Dwayne Cormier
Nov 20, 2018

need ability to turn for conversations that cannot be recorded.

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