Security Circuit using relays to ensure power failure of a device.

Discussion in 'Automotive Electronics' started by wayne.workman2012, Aug 30, 2015.

  1. wayne.workman2012

    Thread Starter New Member

    Aug 30, 2015
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    Hello,

    This is my first post here. I'm looking for some help because I'm fairly a newbie to circuit design of anything more complex than switches and batteries lol.

    I'm looking to power a 12v device in my vehicle - and I want it to be on when all doors and hatches are closed and the starting battery remains intact. If any hatch opens or the starting battery looses connection, I need the power to be cut to the 12v device.

    I'm planning on having a secondary battery and using a 4-terminal solenoid battery isolator to power the 12v device. I'm told that the only safe type of battery to use in this setup is a deep cycle or marine battery... This poses difficulties because of the toxic fumes they give off while charging. I'd really like to use a sealed battery of lower capacity - something like a 65AH solar battery type - but I don't want it to be damaged by the high cranking amp requirements to start the engine. Advice on this problem is greatly appreciated.

    The second issue I am frankly lost on is how to get the power to be cut if a door or hatch opens on the vehicle, or if the starting battery becomes disconnected. I've thought that I could possibly wire a "Normally Closed" relay in parallel with the vehicle's dome lights - so that when the dome-light is powered (regardless of if the bulb is blown), the circuit becomes open. However if the starting battery becomes disconnected - this no longer works. So I would then need a "Normally Open" relay to wire in series with the "Normally Closed" relay so that if the starting battery power is lost - the circuit for powering the 12v device becomes open.

    Lastly - because there are two isolated power sources in this circuit - I'm not sure how to connect the two NO and NC relays with the starting battery and the battery that will be powering the 12v device.

    All help is greatly appreciated... I've been researching this for hours and I have a GENERAL idea of what needs bought and done - I just don't know exactly how to connect it all and I'd rather not burn out any components when trying to figure it all out ;-)

    Thanks sincerely,
    Wayne
     
  2. BR-549

    Well-Known Member

    Sep 22, 2013
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    What is the “device”? What does it draw?

    You will need a wiring diagram for the car.

    Why does starting battery NOT remain intact?

    Do you want to switch back to starting battery, when it becomes intact again?

    Why not tell us what you are doing?

    If we don’t know, it’s a time consuming guessing game.

    We will have to eliminate one by one all the conditions.................and draw more details.

    If you tell us what you are doing, we can get right to the heart of the matter.
     
  3. wayne.workman2012

    Thread Starter New Member

    Aug 30, 2015
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    @BR-549 Thank you for replying. I will further explain what I'm doing.

    I'm planning an installation of a PirateBox in my car. I plan to use a battery isolator and a secondary sealed battery to power it - and have an always-on platform to facilitate free and anonymous communications as is assured to U.S. citizens by the 1st and 4th Amendments of the constitution.

    Here is more information about the PirateBox project - http://piratebox.cc/

    However - with this setup comes the possibility of "illegal" usage. With the PirateBox being totally anonymous, the facilitator of the PirateBox then becomes liable for hosting and facilitating illegal activities.

    Thus there needs to be protections developed to protect the facilitator against malicious and illegal activities of anonymous users. Encryption is obviously out of the question since it would inhibit the free exchange of communication and files.

    To solve this, I plan to have volatile storage (a ram drive) - and a display message for acceptable use that anonymous users must accept in order to proceed, along with a cron-tab script that will delete all uploaded files every hour - on the hour. In the event of seizure, all storage will be lost due to power failure - and in the event of no power failure - all storage will be wiped every hour.

    Obviously physical security then becomes a concern - so some sort of automatic power-loss feature is necessary. Because the unit is inside an automobile, I plan to tie into dome light power (in parallel) with a default-state-closed relay which will kill power to the PirateBox whenever the dome-lights are on. This should ensure that in the event of seizure - when the physical security of the car is breached, all storage is lost immediately. The power flowing through the default-state-closed relay should be fed by a default-state-open relay powered by the vehicle starting battery. So should the starting battery be disconnected - power is yet again lost.

    I've jokingly started calling this the AutoPirateBox, perhaps there is a better name... The sole purpose of this is to have an always-on PirateBox while protecting the facilitator of the platform.

    Any help with this project would be appreciated because I've not done something like this before - however without help I'm going to press forward as I am able.

    The Raspberry Pi platform and Flash-able routers are normally preferred for a PirateBox setup - but these devices don't have adequate RAM for a volatile RAM-Drive. Thus, I intend to power a solid-date fanless intel Atom motherboard with the largest amount of on board RAM that is available for the board.


    I plan to use this motherboard simply because it supports up to 8GB of ram and has a built-in 12V DC-in port which will make it extraordinarily easy for me to power within my car, thus avoiding DC-to-DC ATX power supplies altogether.
    http://www.ebay.com/itm/Jetway-NF9N...board-Power-/131403937313?hash=item1e9848f621 And for the OS, I plan to use Devil-Linux on a read-only USB-To-SD card drive with the write-protect switched on. Here's a link to Devli-Linux http://www.devil-linux.org/home/index.php

    So with the above equipment - along with a WAP (wireless access point) made by TP-link that is powered by 12v 1A like this one here: http://www.newegg.com/Product/Produ...gclid=CI2mwsOu0ccCFVg6gQodmPEKYQ&gclsrc=aw.ds


    I don't expect the power requirements of this system to exceed 50 or so watts.

    I fear I've over-complicated my reply... I need help with the power lol.
     
  4. BR-549

    Well-Known Member

    Sep 22, 2013
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    Just so I understand here,...........................you want to do this............. “liable for hosting and facilitating illegal activities” and take the word liability out of it.

    But still do it.

    Right?
     
  5. wayne.workman2012

    Thread Starter New Member

    Aug 30, 2015
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    @BR-549 lol, I want to facilitate legal activities of anonymous persons.

    the first 10 amendments to the Constitution (the bill of rights) are there to protect the rights of U.S. Citizens. Of course these rights have legal limitations. Such as freedom of speech. You can say what you wish, but you may not threaten to hurt anyone. You may bear arms to protect yourself, your family, those around you, and so on - but you may not use armaments as a tool of assault - and so on. The Wal-Mart employee that sold a shotgun legally to a customer is not liable for a murder committed with said shotgun - no more am I liable for facilitating the 1st and 4th amendments.

    In essence, your front yard does the same thing as what I'd like to do with my vehicle. Anyone two people could stand on your front yard and talk and exchange anything they wish - and you might not ever know they were there - and because there are no records of what happened or who the persons were - it's totally anonymous. And without a No-Trespassing sign posted, it's absolutely legal.

    What I will do is perfectly legal - and I'd rather not argue about it's legality here - but I felt I should try to clarify. If you would rather not help, I understand and respect that.
     
  6. BR-549

    Well-Known Member

    Sep 22, 2013
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    But you do realize that people could do illegal things with your set-up, and you just want to be able to destroy the evidence of that fact.

    That itself is illegal. Once a crime is committed, your set-up becomes evidence, not personal property.

    You can say all you want with your mouth and on paper.

    But once you put it on a carrier..........it becomes regulated and limited.

    A carrier is in the public domain, not the private.

    You want to make sure that the government obeys the law, but you want a way to skirt out of it.

    Typical.

    I have two FCC licenses. I will not help you.

    You have become what you profess to hate.
     
  7. wayne.workman2012

    Thread Starter New Member

    Aug 30, 2015
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    Thank you for your replies. I will continue to seek help and learn on my own.
     
  8. crutschow

    Expert

    Mar 14, 2008
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    So what type of "illegal activity" are you referring to? Porn, terrorism???
    What's the range of this device?
     
  9. wayne.workman2012

    Thread Starter New Member

    Aug 30, 2015
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    @crutschow The sort of potential illegal activities is any that may involve file sharing and text-based communication. These are the activities that I will discourage with a usage agreement, and protect myself from by deleting all files each hour and by not recording logs.

    I feel we can't simply discard the ability to communicate freely simply because someone might abuse the ability. If this logic were used in every instance, we simply would not have the 1st amendment and would prohibit people from speaking freely completely. We simply would not need police officers to obtain search warrants first to search wherever they wish simply because someone might have something illegal. We simply would not allow people armaments to defend themselves because some might commit crimes with arms. Our 1st and 4th amendments are rights - which means they are guaranteed to us, along with all other rights.

    Several companies with this model already exist. One is no-log VPN technologies such as PrivateInternetAccess, others use encryption models so that the facilitator can't know what's on their systems, such as Mega.nz

    Technologies cause the change of laws all the time. Land property rights used to extend to the core of the earth and upwards indefinitely to the heavens. Then the wright brothers invented powered flight. In order for mass transportation to occur without obtaining the permission of every single land owner that an air plain might trespass illegally upon, the supreme court ruled that property rights of land owners can no longer extend to the heavens due to this new technology. This is just one example.

    I might add that phone calls operate on a carrier that spans the country and are protected by the 4th amendment as well. Anyone may say anything over the lines - without any log of what was said.

    The range that I aim to achieve is the maximum that I can obtain from short-range 802.11x technology (roughly 250ft with a very high powered access point). There is 802.11y that offers a 5,000 meter range - but I don't have interest in or means of obtaining that technology - nor do current laptops and smart phones have the ability to interface with 802.11y

    I feel I jumped the gun by posting here - I can probably figure this out on my own but was wanting professional advice for the circuit. I respect others right to choose to not help.
     
  10. crutschow

    Expert

    Mar 14, 2008
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    Well, you gave the impression that you knew you would be hosting illegal communications, and that's what triggered the negative responses.

    Who do you expect will be using your Pirate Box?
    It seems odd to have one in your car.
     
  11. wayne.workman2012

    Thread Starter New Member

    Aug 30, 2015
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    @crutschow Anyone that stumbles upon it may use it legally - and likely will use it if they stumble upon it. I want it to be mobile so that the technology becomes more known about - having it stationary only offers it to a small group of people.

    The nature of WiFi currently is that people want it - lol. Kids are always looking for free wifi, I'm always connecting to free wifi. People frequent McDonnalds simply for the WiFI - they will go in and buy one coffee, then sit with their laptop for two hours. However - if communications can be facilitated without the need for centralized services such as Skype or Google Chat or FaceTime - then this better protects the privacy of users and therefore promotes the 1st and 4th amendments.

    When people see this open WiFi that is available to them, they might try to connect. And when they connect - any DNS query issued will be redirected to the hosted PirateBox site (this is how PirateBox works). Then they may upload files, download files, or join the chat room - all anonymously and totally offline.

    And - to protect myself and others in the efforts to spread the technology - I am intentionally further limiting how long content may be stored - and making that content volatile in order to protect the facilitators of this technology. Once the project is built, I plan to share the build plans on the PirateBox's site.

    Why not watch a short video about the project?

     
    Last edited: Aug 30, 2015
  12. wayne.workman2012

    Thread Starter New Member

    Aug 30, 2015
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    Additionally, If I thought I was doing something illegal, I wound't be doing it, I wouldn't ask for help online, nor would I ask for help online using my real name. :)

    You might also look here, pirate box is already available on Android via Google Play, however I disagree with building it into a platform designed to spy on you. https://play.google.com/store/apps/details?id=de.fun2code.android.piratebox&hl=en

    I might also add that I can setup a wireless network in my home or via my smartphone whenever I please - and that smartphones and home routers enable this.

    I also have absolute legal authority on how long files are stored on any system that I host.

    Please help me with this circuit.
     
    Last edited: Aug 30, 2015
  13. tom_s

    Member

    Jun 27, 2014
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    12v relay normally closed connections on the power to the device hooked up to the interior light (just in case the door gets opened - like you typed)

    why? vehicle left unattended? battery goes flat, power off - no problem

    would be a lot easier to use macca's free wifi. should be able to pick it up from the car park or a yagi antenna

    [​IMG]
     
  14. crutschow

    Expert

    Mar 14, 2008
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    How will you charge the secondary battery?
     
  15. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    So, naturally, you realize your box will be wiped of content and the OS must be loaded and configured each and every time you enter or exit the car...
    You also want a complete loss of memory should the starting battery be disconnected.
    Are these your terms as I interpret them?
     
    Last edited: Aug 31, 2015
  16. wayne.workman2012

    Thread Starter New Member

    Aug 30, 2015
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    @tom_s Thank you for your reply - the secondary battery is to prevent the primary battery from going dead in the event that I don't start my car for a week or two. :-\ I'm not familiar with Macca's free wifi, although it sounds like it's not what I'm looking for. I'm setting up an isolated, offline intranet with limited range.

    @crutschow I was under the impression that the four-terminal solenoid battery isolator would join the two batteries together in parallel once the ignition power was turned on - if wired correctly of-course. I researched how RVs work and found out about battery isolators and then did a lot of research on those specifically.

    @Kermit2 I will setup Devil Linux and the project before hand before enabling the write protect on the SD card. Every power cycle should result in a clean wipe and clean boot exactly as I set it up. The idea is not to destroy the OS and setup - but to destroy any uploaded files or any logs that the project developers MIGHT have overlooked. I'm going to take additional steps to keep things clean while the system is running. But generally, yeah you have the terms about right.
     
  17. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    To keep power drain to a minimum your solution using relays would best be accomplished with "latching" relays. You can keep your secondary battery charged using diodes in the proper location and including with a suitable solar panel for additional power input during daylight periods.
     
  18. BR-549

    Well-Known Member

    Sep 22, 2013
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    You could call it the Hillary server.
     
  19. wayne.workman2012

    Thread Starter New Member

    Aug 30, 2015
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    So - I found this on ebay and it's pretty cheap, it does not say if it's normally open or normally closed: http://www.ebay.com/itm/1-Channel-L...ch-/201316566312?_trksid=p2141725.m3641.l6368

    But I've already ordered one each of these on ebay:

    $1.99 - 4Pin 12v 30A Auto Automotive Alarm Relay For Lights Car Boat Normally Open
    $11.33 - Durite - Relay Mini Normally Closed 20 amp 12 volt Cd1 - 0-727-02

    How would I use a diode??
    I was thinking of ordering one of these two:
    http://www.carid.com/tow-ready/3-po...-118665.html?gclid=CJzhm6701scCFVc7gQodxXoIZg
    http://www.ebay.com/itm/like/151757541499?ul_noapp=true&chn=ps&lpid=82

    And I was thinking of a dash board solar panel, but I was looking at their output and have been arguing about how worthwhile it would be. The highest output one I saw in Google Shopping results was 1.8 watts... and that's nothing compared to the potential 40 or so watts that the system I'm planning will draw. To be totally honest - I was more leaning towards having a larger secondary battery bank (perhaps two 65ah solar batteries) - and a higher output alternator for my car. But I'm super concerned about the fumes from these batteries... all that rapid charging while I'm driving... I'm not sure about it - which is why I am highly curious about the potential damage that the high starter cranking amps might cause to sealed solar batteries.

    Basically, I would just really like to use sealed batteries for this that won't give off fumes - and either two smaller ones wired in parallel or just one really big one.
     
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