security through obscurity? LOL
CAD drawings of what? Isn’t this a case of making an NFC-enabled keypad box replacement if possible, and another control PCB to talk to said replacement box is the original PCB doesn’t play ball?
I only half-way did… I didn’t set up the app or anything but I did put batteries into it to see if it did anything… I also tested the switch, which seemed to do nothing… but I didn’t actually link the pin pad (took it apart immediately) so … egg’s on my face because…
By sheer coincidence, I happen to have some magnets lying around… it snapped right to it. Upon closer inspection of the PCB, this little fuzzy looking component right here…
… turns out to be a hall effect sensor. me wrong.
the question I have now is … why? why go through the trouble since it’s not weatherproof by any means… why not just put a mechanical switch there? it can’t be due to wear concerns on a mechanical switch because honestly… who’s going to turn this thing off and on again on a regular basis? it boggles the mind.
Also…
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Trust what you see, but verify
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Sooo… I made something. It’s not secure, has a less than 2 day battery life, and is quite a bit fugly on the inside… But I can use my NExT to enter my house.
I was able to rope in some classmates to help design this thing for our pre-capstone project in 3 months. It’s all open-source and freely available to put together. Please excuse the terribleness in the design, documentation, GitHub management, etc. Many pictures, documents, and designs here to look through including STLs and a Fusion 360 archive file (I have a seriously terrible timeline I’m sorry.)
The goal of this project was to be able to use RFID/NFC on the existing lock on a rental with a minimal outside footprint. No extra holes needed for the reader. This comes with some security problems, however, for me the convenience is great! The way our door is placed, however, it’s quite uncomfortable to contort my hand to scan correctly, so I’ve ended up using other NFC tags more regularly.
It uses an ESP8266 module on a custom breakout board PCB based on Adafruit’s Feather platform. Designing a PCB was a requirement for the class, but this can entirely be made with a Feather and is my recommendation since it has LiPo charging circuitry. To use this on a daily basis, I’ve had to wire in a micro usb cord to power the ESP. This is due to using a prebuilt RFID project, ESP RFID that we have modified to work with a servo. Our board bypasses the USB power to pull directly from the AA batteries so not to tax the LDO, however, this means batteries are still required even when using power. Using an Adafruit Feather with a lipo would definitely solve this limitation.
Our specific implementation uses a cheap RC522 module, but can easily be used with other modules thanks to the good folks who made ESP RFID.
I’m currently testing out our implementation on my door and so far so good. I’m most likely going to replace the 3x AAA batteries with a small lipo charging circuit due to needing to change the batteries frequently.
All in all, this was a super fun project to work on even though the implementation is quite a bit limited.
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Who cares?
It is an awesome project,
IT WORKS
and it is all “faults” are things than can be tweaked and changed, as and when you have the time and inclination.
Thanks for the share 
and good luck with the assignment 
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Why?
I’m not physically changing the lock, so our crappy Kwikset is one. It’s made of plastic, so it’s possible to yank it off to pry at the lock. ESP RFID just reads the UID of the cards as well. Mostly hyperbole since it’s secure enough for me. 
Right okay. Well, in fairness, you’re not a lockmaker
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You are being a little tough on yourself
Yeah, Maybe 2 Mins to defeat
Do you have windows???
2 Secs to defeat
It is still a physical barrier, and a lowly thief will likely look for an alternative / easier means of entry. They may check out your backdoor 
or
See window comment above
If they see electronics, rather than “hack your system”;
See window comment above
Also
If not the window, they may deploy the Size Eleven tool 
Do you see the theme?
Locks only keep honest people out!
Your lock project is a means of convenience for you, and it looks like it is doing that job perfectly
Exactly 
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Would it be possible to use a spark 1 or a flexMN to activate the SHS-3321?
spark 1 is iso15693 so no there… and flexMN cannot emulate a 4 byte mifare classic, so only older shs-3321s with older firmware will work, or you can downgrade your firmware…
So what your saying is a flexMT will work then?
Yes, yes I did really neat unit the problem I see it is there are alot of small parts and other bits that don’t make it ideal for the community project.
So I will be starting to put my home system together soon. My plans involve a combination of online and ‘offline’ servers/sensors. Do you have any good pointers from your experience putting together and refining your systems?
It has been 6 months that I am waiting to move to my new place (I got stuck with the worst solicitors in human history).
So currently my systems are all in boxes and breadboards waiting to be unpacked, assembled and only then end-to-end tested.
I also “borrowed” a little from some secure facilities I’ve dealt with, so I’m thinking about re-writing some of the bits so I can actually make a shareable comprehensive post about it. 
These are some of my thoughts/plans on it:
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I’m setting the lock mechanism on the strike plate side, not on the door.
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I won’t rely on batteries. the system will be hooked to a no-break battery and to power mains.
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I’m still thinking how to set up a reliable notification system for every time my no-break kicks in
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all the installation sits inside the walls
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reader will be set up flat to the external wall, behind the wall-paper (I’m moving into an apartment building, so there is wallpaper. You could use a very thin layer of plaster possibly for a house).
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The door and handle will remain unmodified, as to not draw unwanted attention. (The more secure your house looks, the more it attracts crooks who believe if you spend that much in security it’s because you have valuables…)
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I’m using a raspberry pi zero, but if you want a more professional look you could go for arduino instead. My choice for raspberry comes partly because I already had a lot of the GPIO code ready (“borrowed”), partly because my only means of access to it once inside a wall will be ethernet.
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If I can’t find v1.31 of the raspberry zero (best revision of the board without wifi), I get the newer versions (W) and fuck the wifi module. I also fuck up the BT module just in case.
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If going for raspberry and you want to use a newer model, I strongly advise against anything stronger than a Pi2. This is because you seriously won’t need the performance gain from 3 onwards, and such stronger processors also require a much steadier power source. Therefore any drops on current will cause it to reboot. Older models can work on less stable current with less of an issue.
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Raspberry uses GPIO to control a relay switch to trigger the door plate.
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When buying the wall plate, make sure you buy the right model: there are “off closed” and “safe - off open” models. I obviously chose off-closed because don’t want my door unlocked if power goes down.
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I’m considering if to use a mechanical or mechanical + electrical door closing arm (forgot the name. that thing which closes doors from the top)
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I hook up the raspberry zero to an ethernet module, a cable from it to a dedicated ethernet router, with no wifi capability, stick that inside a wall and leave only one point of access, through ethernet, on a port behind a panel.
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I log everything through that ethernet router, onto a dedicated raspberry, a tiny bit more accessible (i.e. behind a screwn-on wall plate. only meant for emergency access).
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that dedicated logger raspberry uses a sim card dongle to send SMS messages, pre encrypted, to an aws endpoint, which can pre-analyize, notify myself if anything weird might be happening (inclusive of no logs showing up), then cold-store it. (SMS are free here and is a good compromise to enabling some “network communication” without actually being on a network)
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SMS dongle set up to disregard any and every message coming back.
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when embedding things onto your walls, use internal walls! never a wall shared with your neighbours.
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I am considering if I should brick the door handle. this way no one can pick it.
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I am still considering which mechanism to set in place as an emergency release. currently considering bricking the handle and setting up a ferrous base behind the pin, then a very strong magnet hidden behind the skirting board… but that just seems like too much work
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if you want remote control, I recommend using the SMS module for that (then locally instead of on a logger, and sanitise, instead of disregarding, any SMS input)
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considering adding an electronic, online, magic eye.
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adding a camera hidden on a mirror at the end of the main corridor, facing the entry door.
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I am still messing around to decide if I’m going forward with an USB based ACR122u/PASORI, or a GPIO mounted Wiegand reader. Wiegands reach a better range, but so far they are proving a bit fiddly to read, given GPIOs not being as precise/fast as Wiegand, thus causing some data to be lost here and there… Still hoping to find better range on another reader…
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I’ll soon rewrite the tag code and share it (once I strip the proprietary bits off of it). The core logic behind it is… read an UID → check against a file which states either: A) open and notify me. B) challenge DF2. Option A is just a backup functionality, doesn’t need to be in place, but allows me to register any HF chip as a “guest” temporarily. Thought of that in case I have guests with their own implants, so I don’t need to hand out some nfc wristbands neither write an application to their chips.
Access is granted based on a file I can edit using ssh through the only ethernet port mentioned, and sshing gets logged and notified to me.
Think those are all my core points. Hope it helps!
Else, just ask away whatever specific you have in mind!
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All this talk of security, and then Wiegand?
Also, consider that the wallpaper will get dirty with time if the read range is not stellar and you have to rub your hand against it (think light switches in apartment buildings), leaving a convenient mark.
The hacks on wiegand depends a lot on how it’s integrated.
Applying it over GPIO and sanitizing it + not allowing plain UID access… would mitigate these risks.
Then if I can get a consistent read range boost (on my tests I managed to gain about 5cm), it would mitigate other issues, such as the wallpaper.
Plus on my case it’s a really dark wallpaper full of leafy drawings, so it wouldn’t get as smudged as a white wallpaper.