What About The ISS?

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JerkFace

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Re: What About The ISS?
« Reply #120 on: June 30, 2015, 06:25:21 PM »
Well, I could look into RFID tags like that, but it needs to be initiated from the door opening, I wasn't thinking about having the base station constantly polling the access points for updates.  I will look into it a bit more.  I did some research on RFID readers for another project during my senior year of college.  I designed a wall avoidance system for a quadcopter and the construction engineering guys wanted to add an RFID reader payload to it to present it as a cost effective inspection platform for large buildings, specifically concrete structures and their RFID tags attached to strain gauges inside the concrete and rebar.

Since you can use them to transmit data from sensors, I guess I could try to have it change its ID based on the status of the door/window.   But that means the base station would be polling constantly.  Gonna reduce the lifetime of my zigbee.

Mikey T.

Can you use a magnet and a NC reed switch that would open the reed when the door opens allowing a line to be pulled up via a pull up resistor. Use a large enough value resistor so you aren't drawing too much current across it. This would generate an interrupt to the processor. Then the NO side of the reed switch would complete the circuit for the RFID device. Then the processor would poll all the RFID devices to see which one generated the interrupt and will communicate. I guess you would only need one wire for ground. Is this any help?

Yendor

Yendor,    I think Mikey is more concerned with how to provide enough power to transmit the door/window status,  that just simply detecting open/closed.   In any event security systems often don't just use digital open/closed type inputs,  the ones I've worked with are analog inputs, and measure the current through the switch/sensor  to detect tampering,  for example a burglar tries to bypass the switch with a short cct,  you can detect that by sensing increased current, just as easily as an open cct.   

Mikey,   I've used zigbee,  in both point to point and mesh configurations,  I think you'll find it tricky to get enough power,  even with a sleeping end-point configuration.    I've only ever used that with batteries,  and solar,   There are other wireless options,  but it depends how far down the track you are with zigbee.   If you haven't already committed to zigbee,  you might look at wifi using ESP8266 or similar.

Yendor,   Solar panels are fully insulated on all sides including terminals,  if you were to come in contact with the exposed cabling from a string of panels in series then you'd have to break through an enclosure to do so.   The danger of an astronaut on the ISS getting electrocuted by solar panels is vanishingly small.   Even if they took the covers of the junction boxes, they are wearing gloves which would provide some insulation.   They could climb all over the panels themselves and not get zapped,  but,  I'd guess they might mechanically damage the panels. 

Stop gilding the pickle, you demisexual aromantic homoflexible snowflake.

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Mikey T.

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Re: What About The ISS?
« Reply #121 on: June 30, 2015, 07:43:02 PM »
Yes, But zigbee gives me a bit more flexibility with the coding of ID in the signals so I don't have any crossover from the neighbors house or interference from an internet wifi present in the house or the neighbors.  Plus there are smart bulbs and smart plugs already on the market that could be incorporated into the monitoring and control from the system.  I do have a few Z-wave chips (love free samples), I have thought about bluetooth also, and wifi just has too many issues and a little higher on power consumption, I think. 
I am thinking on making a secondary receiver for just the door and window access point devices that just awaits a burst type transmission on a fairly low frequency while keeping the overall system on zigbee for expandability with other market items.  The main issue there would be noise levels.

See, I am still getting sucked back into this discussion lol.  Well I tried modestman, I really did.  I just can't help myself when it comes to this type of stuff. 

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Mikey T.

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Re: What About The ISS?
« Reply #122 on: June 30, 2015, 07:47:03 PM »
And yes you are correct, I have a multitude of different style sensor types that I could use for the door and windows, my main concern is the power for the signal broadcast.  I was toying with the idea of having the sensor be able to generate enough power from the mechanical movement of the door to send its own signal out.
Yeah i am trying to cheat a bit by not having anything to read the sensor then send the signal out.  My thoughts were if the sensor was passive and the movement of the door would generate enough power then I would not need a sensor and transmitter, the power from the movement would activate the transmitter.  I guess that makes sense.

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JerkFace

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Re: What About The ISS?
« Reply #123 on: June 30, 2015, 08:28:41 PM »
There are a lot of solutions in that  application space,  short  range low power sensing.    I've used zigbee,  and you can make battery powered end-points with nano-watt level power consumption,  but when they wake up and transmit,  you need 20 mA or so,  that's a problem if you don't have batteries.   

The ESP8266 with it's built in tcp/ip stack and low power modes will integrate more easily with smart phones, tablets and allow remote internet access more easily.   Cheap as chips too.

The microchip keeloq system is low power rolling code transmitter,   like car door lock systems.   Is potentially the cheapest and lowest power option.  But development time is probably longer, and integration with existing systems would be problematic.

I mostly use microchip pic stuff,  but  lately  doing a lot of interface boards with the Intel Edison,  I like it better than raspberry pi.

Stop gilding the pickle, you demisexual aromantic homoflexible snowflake.

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Yendor

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Re: What About The ISS?
« Reply #124 on: July 01, 2015, 06:36:10 AM »
Rayzor,
Thanks for the info on solar panels. I guess I was speaking out of turn because I never have really worked with them.

Yendor
"During times of universal deceit, telling the truth becomes a revolutionary act."
                              George Orwell

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Yendor

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Re: What About The ISS?
« Reply #125 on: July 01, 2015, 06:49:12 AM »
Mikey T.

Is there anyway you could use a coiled spring that would unwind when the door or window opens. the spring would be connected to a small generated. That may give enough time to generate a code. A knob on the front would wind the spring back up. It is going to be hard to do without batteries.

Yendor
"During times of universal deceit, telling the truth becomes a revolutionary act."
                              George Orwell

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11cookeaw1

Re: What About The ISS?
« Reply #126 on: July 03, 2015, 12:25:45 AM »


400km  is 1312336 ft.  Here is a photo at 120000 ft http://swns.com/wp-content/themes/wp-clear/scripts/timthumb.php?src=http://swns.com/wp-content/uploads/rower1-1024x768.jpg&w=600&h=450&zc=1
Definite curve there.  Looks like the earth is round after all.
Tickets please .All aboard the bullshit train . Full streaming shit ahead. Anther supply rocket blows up . That makes 3 if you include the Russian.
What are they breathing up there . What are they eating  & drinking up there .  Dame that shitter must be backed up to the hill . You can only survive on fairy dust shit talk for so long . I, d be a little worried if I was one of those nasa astronaut actors . They might  just  have to take one for the team soon .


400km  is 1312336 ft.  Here is a photo at 120000 ft http://swns.com/wp-content/themes/wp-clear/scripts/timthumb.php?src=http://swns.com/wp-content/uploads/rower1-1024x768.jpg&w=600&h=450&zc=1
Definite curve there.  Looks like the earth is round after all.
Tickets please .All aboard the bullshit train . Full streaming shit ahead. Anther supply rocket blows up . That makes 3 if you include the Russian.
What are they breathing up there . What are they eating  & drinking up there .  Dame that shitter must be backed up to the hill . You can only survive on fairy dust shit talk for so long . I, d be a little worried if I was one of those nasa astronaut actors . They might  just  have to take one for the team soon .
I can clearly see a slight curvature there.
They breathe using spacesuits.
« Last Edit: July 03, 2015, 12:53:19 AM by 11cookeaw1 »