Olympus

Olympus grants access to the space when locked, entry for members when opening the space at the start of the day, or late at night. It replaces SHED.

https://www.noisebridge.net/wiki/Olympus

How to get access

Preferred method: Ask around in the space for a Big M member to provide access

There is a box of free RFID cards behind the OLYMPUS system, near the mailbox. You may use one of these or use your own clipper transit card / RFID card. If you are using your own RFID card, please tap on the blue PCB and it should say "Access Denied" if your card is compatible. If you tap a card and it says nothing, it is likely that your card type is not supported. Only Mifare Classic cards are supported as of this writing.

Instruct the Big M member to follow the directions in the How it works section of this page.

Manual method: Send a DM to solderfumesandtea on Discord

First obtain a clipper card or get an RFID card from the box of RFID cards behind the mailbox. If purchasing your own card online, make sure it is a Mifare Classic type card. Tap the card on the blue PCB and it will display an "Access Denied" message followed by a string and numbers and letters. Send a picture of the access denied message to Solderfumesandtea on Discord. If the screen says nothing after tapping a card, likely that type of card is not supported and you must use a different one.

How it works

Opening the door

Tap your authenticated card onto the blue PCB.

Big M Member giving 30 day access

An authenticated big M user will first flip the safety toggle switch to the on position. The OLED screen will display "SUDO mode engaged". The new card being given 30 day access must then be held against the RFID scanner. The screen will confirm that access has been given and a QR code to a Google form will be presented. The new user must scan the QR code and enter their name / handle.

Big M Member giving associate / philanthropist access

An authenticated big M user will first flip the safety toggle switch to the on position. The OLED screen will display "SUDO mode engaged". Once the "SUDO" message has been displayed, immediately turn the toggle switch to the off position. Now press the new card onto the blue PCB antenna. After some time the screen should confirm that access has been added and a Google form will pop up. Fill out the Google form and the process is complete.

Big M member giving big M member access

Adding big M access is the same as 30 day access, however the red push button must be held down during the process.

Status

Done

• Prototype that scans rfid cards, stores in database, unlocks door.
  • Allows adding new keycards
• Finish splitting the hardware into "brains" section--secured--and sensors section, lives outside--insecure.
  • Installed.
• Find way to deliver enough voltage and current to switch solenoid. Tried, not worked: voltage divider (high-resistance) and boost converter and signal-level converter (3.3V - 5V). More in #Rough Notes
  • Fixed by using a TIP120 mosfet, the threshold voltage for switching on the solenoid circuit was lower with this component

Next steps

• people given 30-day access aren't able to change access ;(

Intro to development

Keeping in mind User:Mcint/Project Derisking:

• Problem: Needs to fulfill a few purposes. First in the order people might think about them, or naturally state them, before we decompose them into functional requirements, or simple solutions that aim to satisfy multiple naive user specifications (in a creative and minimal way if possible, instead of via extensive requirments).
  • Grant entry to members. When a valid key is presented, only when a valid key is presented, unlock. Grant entry to some users only during open hours.
  • Make addition of new temporary members easy. Make auditing list of people (/keys) with access possible. Make revocation possible.
  • (Possibly report (live)/record (for later review) entry attempts, failed (or also successful).)
  • (no others named, challenge)

• Solution:
  • Outside
    • RFID Scanner: RFID-RC522. Vsrc, Gnd, 5 pins in use. (1 ethernet cable. 7/8 wires.)
    • Screen. Vsrc, Gnd, +~2 pins in use.
    • Switches, 2. 2 pins indicator, share Vsrc, Gnd. Switch "add user" mode, push-button "member" modifier.
  • Inside
    • RPi. 40 pin. https://pinout.xyz/
    • Secured: in wall-mounted box, or in lockable mailbox "suite 1", or not locked, "suite 2".
  • Connection: 2 ethernet cables.
    • Serve power/ground over both (to support smaller standalone components for testing & debugging).

Software

• https://github.com/Daniel-Alnasir/OLYMPUS
• Daniel wrote. https://github.com/tooPhatJones/NBCardreader (farley uploaded, old)

Rough Notes

• I2C over long wires

Service Commands

# denotes root, so either prefix each command with $ sudo ..., or enter a rooted interactive shell with $ sudo -i before running the rest of the commands.

• # systemctl status olympus[.service] - shows current status, and the last few lines of logs.

• # systemctl [start|stop] olympus[.service]

• # journalctl -eu olympus[.service] - looking at [e]nd of logs, freshest lines, show logs for [u]nit, immediately next argument must be unit name(s).

Switching power / 2023-09-11+

• Suggested "HiLetgo PN532 NFC/NXP/RFID Module, v3" ($9) for RFID, maybe better range, "less spooky".
• We might be able to drive the solenoid with 3.3v and just the boost converter
  • 3.3 v gpio
• https://www.electronics-tutorials.ws/transistor/tran_7.html
  • See MOSFET characteristic curves: https://www.electronics-tutorials.ws/wp-content/uploads/2018/05/transistor-tran56.gif
    • y intercept of the red line. I = V/R --> high R -> low I
    • https://electronics.stackexchange.com/a/195080/310501
      • for door solenoid: falstad, n-MOSFET, beta->80 as suggested for power mosfet in beta info, 12V drain (src - gnd), 3.3 V, ---> shows 67mA of current. I wonder what the door solenoid needs

sampling of amazon door lock solenoids	reqts
https://www.amazon.com/UHPPOTE-Standard-Electric-Strike-Control/dp/B00V49S418?th=1	Working Voltage: DC12V / Current: 320mA
https://www.amazon.com/Seco-Larm-SD-995C-D3Q/dp/B07G58CS9F	Current Draw: 300mA@12VDC, 150nA@24VDC
https://www.amazon.com/UHPPOTE-Standard-Fail-Secure-Fail-Safe-Adjustable/dp/B00V49S2NI	Input Voltage: 12VDC; Current: 220mA

• falstad simulation, with beta from above
  • oh, so 67mA is too low a current to switch it, by factor of 5
  • the gate voltage ~3.8V to trigger, matches
  • err, sorry, too few mA, 12V, about half. it's a plausible range for some solenoid, idk which we have
  • it turns out more drain voltage has no effect on drain-source current, only gate voltage affects drain-source current --- as ..expected / desired
  • I calculated beta of 3 from the data sheet -- i think -- https://datasheetspdf.com/pdf-file/283681/FairchildSemiconductor/IRF520/1
  • it shows over an amp at 3.3v -- we're clearly in the right range
  • maybe the buckboost* converter is current limited, from rpi 500mA limit
    • but the boost converter halves current in exchange for doubling the voltage

Data Model

Users

{
  "0x8800112233": {
    "clearance": "Guests",
    "expire_date": 1697010653135.815,
    "issue_date": 1694418653135.815,
    "exp": "2023-10-11 00:50:53.135815",
    "iss": "2023-09-11 00:50:53.135815",
    "uid": "0x8800112233",
    "user_handle": "j p hacker",
    "mentor": "0x8800112211"
  }
}

Design Requirements

As initially conceived, and in further requests from the space.

• Members
  • 24 hour access
  • Can add guest users.
• Associate members (not implemented just yet, Wyatt has an open PR for it)
• Guests
  • 30 day access, business hours.

We are using RFID to allow access. We would like to associate names with that, eventually excluding users without an associated name.

We plan to report user additions to a public channel, and accesses to the space.

I would like to blind the data file by HMAC'ing the IDs with a private key.

Guiding Constraints

In order to make the system useful in an enduring way, and useful across more doors than just the front, these guiding constrains were proposed:

• Easy/cheap to replace
• Easy to modify the code base
• Obvious for a user to understand the UI for badging in and getting access.
• Difficult to damage/disable

Using

Instructions appear on the screen within 1-5 seconds, explains itself, mostly.

• Scan RFID, access granted (/denied), door unlocks.
• Add user: admin user enables "new user" switch, scans admin RFID, scans new user id (with or without "member" intensifier). Added users have immediate access.
  • New members must scan QR code, add name/contact info to google form, and submit for approval.

Managing

• Firebase database manages the UID, raw from RFID.
• New users via google form. QR code link, with RFID UID, shown on screen for enrollment.

Wants & Future Directions

• Blind RFID values read, stored, & shared. Hash (with salt), or HMAC. In database, and uploaded in gForm. (Prevent snooping & spoofing "credentials" - RFID is just ID, no secret / password / challenge.)
• Report additions (blinded / without UIDs) to Discord & Slack (via RSS?).
• Look into self-hosting database. https://nocodb.com, self-hosting (self-hosted ~Airtable + APIs. Auth handled.)
• Integrate User:Mcint/Projects/Member system.

Naming/Lore

• There exists a locked Slack channel called shed-gods where the management of access control took place.
• Gods should live at mount Olympus not a SHED.
• Project is named Olympus as a subtle nod to the old way of "Gods" managing access control on Slack.
• SHED name is also confusing to those unaware of the concept of bike shedding. People may have been looking for a literal shed.

Ancient Wisdom

• SHED - the system made 3 years before this one
• Earl - RFID access control system at 2169 Mission St, with source online
• Access_Control - repo to Earl, the access system made 8 years before this one; ideas/proposals for improvements
• RFID_Token#More_about_Earl,_the_Access_Control_System - the past four-level-tier-system
• Access_System#Disclaimer - the philosophy of access controls