Existing intercom system

MisterBill2

Joined Jan 23, 2018
6,755
Me thinks thou doth protest too much. A little exaggeration perhaps?

Arduino’s, power supplies and programming cables are often bundled. Calling out the individual components is misleading.

Besides, once you have made more than one Arduino project, you’ll likely have extra programming cables. There is nothing special about an Arduino programming cable; it is a standard USB-B to microUSB cable.

You’ll need a power supply no matter what. So calling out the need for an “Arduino” PS is disingenuous.
The TS is a commercial electrician, not a hobbyist. And the fact that possibly the cable and the other accessories might be included does not change the fact that they will be required. And I did neglect the effort to program the device, which from my observation, they choose to use different words for most functions, so the learning curve will not be trivial. Also, the intercom system already includes a 24 volts AC supply, so that will not be an extra.
So NO, I am not exaggerating at all. What is there about a very little circuit designing effort that promotes so much fear in the hearts of arduino followers?
 
I've been in the boat where my stuff lasted 20 years or longer. It was basically a hydride gas selector/detector/shutdown system. All 3PDT Idec octal relays at 24VAC. I don't think 24VAC was the right voltage to use, but I didn't know anything. One contact was the latch, the second, the indicator switch and the third, the alarm loop. There was no audible alarm from this box.

A level one gas alarm would turn off this box and a level 2 would set off the fire alarm.

At the time, I did not know about "monitored contacts". I eventually added a few. One was the contact from the fire alarm which we had to "disable" about 2x per year for fire alarm testing and the system was in a "safe state". My "monitored contact" was a small LED next to the labeled indicator. It went off, if the fire alarm was in "trouble", so we knew when the fire alarm was reset. You pulled an internal connector to disable the fire alarm. At least I asked for an SPDT contact.

My box had 3 conduits. One large one for the contact closure sensors. One for the 120 Vac feed and one for about eight 24 VAC valves at the gas cylinder cabinets. The individual sensor wires

Wires were run by an electrician, but not end point connected.

It got really messy when, the hydrogen and hydride detector were moved outside of the fire wall. "They" wanted to fill the pentrations with foam and I said no because you can't add anything. Again, a large conduit attached to a large enclosure above the ceiling and cord grips for each PTFE insulated wire.

There was also a separate 2 cable conduit for the hydrogen detectors. That wiring had to be separate.

The case/power supply end up being a large part of the cost. Then there is a problem of where to put this stuff and possibly make it vandal proof.

It MIGHT be easier to "disconnect" the intercom button and replace it with a FET opto or small relay and wire the switch to the processor. A fet interface I made was to put the opto, diode and current regulator (LM334) inside the equipment, so you get a 6 to 32 VDC interface.

You might have room for a surface mount box and a key to open with an alarm, but that adds more cost especially if the alarm is at the other end. Make the surface/flush mount box use security screws and a Key to open.

This https://www.alliedelec.com/product/hoffman/afe12x12/70228264/ is a little big, but use tamper resistant screws and a key latch.

Here https://hoffman.nvent.com/en/hoffman/type-1-boxes-and-enclosures shows a flush mount door frame. Maybe mount it so it needs a ladder to access. Then use standard DIN rail construction.

Go to http://images.google.com and do a 'DIN rail enclosure' search.

An example: 1582908812259.png

of say the custom portion containing the CPU.

Here;

1582908998210.png
is an example of something small.

There's a 1/4" aluminum panel on the back and two horizontal DIN rails are attached at the boddom and middle of the box. Nuts in the corners remove the entire aluminum plate. Stand alone relays are attached to the back. So, you use a few tapped holes.

The grey stuff is "wiring duct". It just makes the wiring look neater. The covers snap off.

This method is basically an erector set with re-useable parts. It's great for "one of's" and even production.

There isn't any DIN terminals in there. Look here https://www.asi-ez.com under "terminal blocks DIN rail".
The blocks are 3 sided. You put them together on the rail and finish with an "end cover". You can optiona;;y add "partition plates" which are higher to group terminals. The most common rail is TS32. Then there are "end stops" which prevent movement of the group. There are ground blocks, fuse blocks, single level, dual level etc. There are jumper bars and holes for terminal number labels.

One trick which is very useful is you need to keep power and signal separate. the next thing you need to do is make ALL of the signal wires coming into the box terminate in "one place". From there, they go to their specific places.

I don't think the part is available without making it custom, but I can probably find something close. it's like 10 conductors plug and receptacle with screw terminals. it's probably 1.5" x 5" long. They could be used to terminate the wires, so the panel would be totally removeable.

They kinda look like 1582910586154.png
with horizontal and vertical mounting ears. I used them for odd wiring for temperature controllers like Set point in SP out etc.

There are things called wire ferrules which protect stranded wire.
 
A lot of stuff doesn't make sense.

Why not just open the second door after a "time delay" on the removal of power to the "outdoor strike"?

You could get a little fancy and use a current sensor and maybe accommodate AC and DC strikes.
 

MisterBill2

Joined Jan 23, 2018
6,755
OK, "KSS", indeed that is how industrial stuff is done. Buildings are not always so simple, and very often all electrical must be hidden inside the walls. NEMA boxes are good but certainly not cheap. I have no clues as to what the area with the two latches looks like and so where to put the logic is unknown. I woukld love to do it with a single "TRI-FLOP" circuit and two small solid state relays, and stuff it all inside a rectangular electrical box with two LEDs in the blank cover. But no telling how it will actually work out.
 
Buildings are not always so simple
Agreed. My father was good at running wires. Dad did a wired doorbell and added an extra switch to an exiting 2 gang box.

I need to do wired Ethernet and re-do the telco distribution. I have a 24 port POE gigabit switch to install.
The punch down panel is in place for Ethernet. The telco panel is purhased, but not in place yet,

I had enough trouble running RG-6 for TV to about 8 spots and the roof. One spot, I added a dual-gang low voltage box, but with no connections to it. I even drilled the footer. I did this because the room got painted.
I have the Dewalt stud and joist drill and a flex drill bit. A friend gave me 500 feet of RG-6.

I have two large rolls of CAT6 in two different jacket colors.

Another bed room needs connections too. One would be difficult, because a TV would have to be wall mounted.

The main TV needs an Ethernet connection. I ran telco there because the previous TV implemanted a speakerphone. I'm using the telco connection for a telephone line monitor with a LED above the TV. CAT 3 was pulled for the telco unfortunately and no extra cables were pulled.


==

Do you think the TS would go for a delay for the second srike? On the falling edge of the first strike, start a timer (5-25 s) and then activate the second strike for whatever normal time that is (10s)? That may be off the shelf stuff except for the 24VAC power.

The other suggestion is to use current rather than voltage for both AC and DC strikes. That could be an upgrade for other places.

I can see an outer door and an inner door just as you enter. I can also see an outer door and stairs to another door with a strike. Maybe the second one is not a good idea with stairs.

How about a pressure mat. If your standing in front of the inner door a second buzz will be directed to the inner door?
 

MisterBill2

Joined Jan 23, 2018
6,755
Agreed. My father was good at running wires. Dad did a wired doorbell and added an extra switch to an exiting 2 gang box.

I need to do wired Ethernet and re-do the telco distribution. I have a 24 port POE gigabit switch to install.
The punch down panel is in place for Ethernet. The telco panel is purhased, but not in place yet,

I had enough trouble running RG-6 for TV to about 8 spots and the roof. One spot, I added a dual-gang low voltage box, but with no connections to it. I even drilled the footer. I did this because the room got painted.
I have the Dewalt stud and joist drill and a flex drill bit. A friend gave me 500 feet of RG-6.

I have two large rolls of CAT6 in two different jacket colors.

Another bed room needs connections too. One would be difficult, because a TV would have to be wall mounted.

The main TV needs an Ethernet connection. I ran telco there because the previous TV implemanted a speakerphone. I'm using the telco connection for a telephone line monitor with a LED above the TV. CAT 3 was pulled for the telco unfortunately and no extra cables were pulled.


==

Do you think the TS would go for a delay for the second srike? On the falling edge of the first strike, start a timer (5-25 s) and then activate the second strike for whatever normal time that is (10s)? That may be off the shelf stuff except for the 24VAC power.

The other suggestion is to use current rather than voltage for both AC and DC strikes. That could be an upgrade for other places.

I can see an outer door and an inner door just as you enter. I can also see an outer door and stairs to another door with a strike. Maybe the second one is not a good idea with stairs.

How about a pressure mat. If your standing in front of the inner door a second buzz will be directed to the inner door?
I am thinking that there is a fair amount about this installation that we do not know. Consider that the first door opens into a small vestibule and then one of several doors opens to different offices. So which second door opens is a variable. If there were a door-sensing switch so that the first door had to be closed before the second unlocked then the whole thing could be quite simple. Otherwise it can take more relays.
 
We don't, but we do know that the TS would like to make these generic.

I like throwing out all possible ideas no matter how goofy or expensive they may be, so I threw out the pressure mat. I think the pressure mat really simplifies things unless there are 10 strikes and everyone is standing in front of a door or the UPS guy put a package on the mat, A PIR sensor could work too.

They could be wireless. Linear DXS sensors. I plan to use two eventually. One for motion sensiong in the bathroom for a hot water recirculator and one for a wireless dorbell. These sensors are used in PERS and security sensors, They can have low battery detection and supervision.

I have a PERS system at home. Transmitter lifetime is very long. Like 5 years or more.

Added 2/28. How does one entrance and 3 apartments each on a different floor fit in? Some on the same floor?
 
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MisterBill2

Joined Jan 23, 2018
6,755
OK, now the circuit is all in my head, I just need a few answers from the TS so that the hookup will provide the functioning desired, and the added wiring will be minimized.
First question: Does the second buzz need to ONLY release the second door? OR could it release both of them?
Second question: Is there wiring to bring the 24 volts to wherever this additional circuit is to be installed? Or will it be installed right at the intercom box?
Third question: How much current do the buzzer/release devices need, or draw?
Fourth question: Will you be having somebody competent in electronic building put this thing together? It is not that complex a circuit but it will include one IC device and a small relay, and a transistor. Possibly as many as a dozen components.
 
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