Door control system

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Revision as of 15:04, 13 November 2018 by Simon Hewison (talk | contribs) (Cards that don't work as well)
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The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair.
- Douglas Adams, 'Mostly Harmless'


Front doorbot

The front doorbot at 388 High Road is based on a TI Connected Launchpad, and works alongside the building landlord's door entry system. During normal 'office hours', the maglock on the front door between the street and the shared lift lobby will be unlocked by the landlord's system. Only outside of normal hours will the door entry phone (only used by other tenants), and Hackspace's Front Doorbot will be necessary. Exit button is the landlord's door release button.

The Hackspace card reader is a small blue enclosure on the right hand glass. The reader loop is at the top of the enclosure near the logo.

Front doorbot is in a shared enclosure with the Ground floor doorbot, and has a battery backup. In the event of power failure, it will still try to open doors with cached credentials, though some functions will depend on working networking and working acserver.

The front doorbot sends out notifications using MQTT, to the topic base /door/gf-front-external. Any network device can listen in to these messages and set up their own bot/reporting infrastructure, etc.

Back Doorbot

The back doorbot is the same as the front - with two differences: there's no bell, and the relay is activated by setting the pin state to HIGH. This instance sends notifications to port 50000.

Biohackspace Doorbot

This is the same as above - sends notifications to port 50001. You need to be a member of the Biohackers to get in.

1st Floor Doorbot

Maglock, 1st floor entrance from lift lobby. SLA 12V backup battery. ACNode shield v1. Node id 2, notifications to port 50003.

Rebuilt to make it more like the ground floor / front doorbot, and to implement a doorbell button on the reader.


The source code for the software on the nodes is on Github, the server is here acserver-django

All the logs go over the network to /var/log/network/ on adminstuff, but it's not configured yet.

The access list is JSON file. The acserver should download a new version of the carddb file every 5 minutes from Turing (the machine that runs the website), but it's not working yet.

Notification and status messages go via mqtt to the mqtt server. There's currrently a process that runs on a raspberry pi to take these notification messages and re-generate legacy UDP broadcast messages. Eventually, all the listener clients will subscribe to feeds on the mqtt server instead of listening to UDP broadcast messages.

The door opener broadcasts on the network whenever the door is opened by a member using their card , or if the front doorbell is pushed. The back door broadcasts on 50000, and the front uses 50002, so we can tell the difference between them in the various listeners. This is a stop-gap until we add the door ID to the messages.

Doorbot listener scripts

There are listeners on hamming that connect to robonaut to announce on IRC, and flash the lights using Lighted. By default, this will include your full real name. If you wish to change this behaviour, you can set up a nickname in the cards section of the member area.

hamming also runs listeners for the scrolling led board and the audio announcements.

The announcement listener uses the GLaDOS voice. You can generate and use your own file as a greeting. Update your 'Glados file' with a URL of an audio file, and it will play a maximum 12 seconds of the sample when you enter the 1st floor. File formats supported include mp3, m4a, wav, and non-DRM-protected aac. It will not play 'audio' from a YouTube URL.

The code that runs the bandwidth meter on adminstuff also listens for doorbell and member entry messages.

Adding a card

If you're a new or pending member and looking to add a card to enter the space on your own, be sure you have an RFID or Contactless Smart Card that operates on the 13.56mhz frequency. You likely have several in your wallet and may not even know it. Note that our doorbot RFID readers do NOT read the older 125khz frequency RFID cards frequently used for older 1990s/early 2000s era office/housing access, so not every card works in our system. You are likely in luck and have at least one 13.56mhz card already: the Transport for London Oyster card is by far the most popular card used by LHS members, but several members have also successfully used various hotel RFID keycards, contactless credit and debit cards, and some compatible government ID cards as well.

Cards that are known to work well

  • Transport for London Oyster cards
  • EV charging membership cards (Source London, Polar, GeniePoint etc)
  • BMW DriveNow membership cards

Cards that don't work as well

  • Contactless bank cards have more processing power on-board, and need quite a lot of RF energy to activate, so may not work as reliably as simpler cards like Oyster card or simple keyfobs. This is a known problem, that might be resolved by including a DC boost converter in the reader enclosure to make sure the reader gets a good 5V supply.
  • Passports with RFID chips will not work, and by attempting to use them will reset some internal read count in the passport, which may raise questions at border crossings.

'Cards' that don't work at all

  • Apple Pay
  • Android Pay
  • Most Android card-simulator apps

All of these generate a random UID for each transaction.

  • Tesco Clubcard
  • 125kHz frequency RFID cards (HID building entry systems)

If you still cannot find a capable card, you can buy them relatively easy off of eBay or Amazon UK or a local vendor such as Cool Components

Access is based on the RFID UID - it is not the number written on the back of your Oyster card. There are several ways to add a card:

  1. Use the Membership_Kiosk which is on the first floor. You will need to enter your email address and password.
  2. Run the "Add card to Doorbot" script on Tesla (hint: the shortcut is on desktop) and follow the instructions (basically, swipe your card and then enter your hackspace website login details).
  3. If you have a similar ACR122U card reader, you can get the code at Github and run on your own. If you have another reader that can give you the UID, log in to the website and add it at the Member Addcard webpage. Note that our doorbot code is case sensitive; enter the (hex encoded) ID using upper case letters only.
  4. If you have an Android phone that supports NFC, you can download the free NFC TagInfo by NXP app in the respective Google Play Store. Once you've downloaded and opened it, you'll be able to scan your RFID card and type the ID found in Detailed Protocol Information section of the App and link to your account with your RFID card here. Your phone may need to activate NFC connections/reading on your phone. On Android, you can find this in Config/Settings>Wireless and Network Connections.


If one of your mobile NFC scanning applications reads your RFID UID as 04:2b:2e:6e:fa:bc:de you should enter it into the website as 042B2E6EFABCDE

Do not worry if your card UID is shorter than the example - this is perfectly legal syntax.

There is the possibility for an integrated LHS membership RFID reader app - Hackspace member and former trustee Jasper had built an Android app that automated the previous mobile task but the website changed and the app broke. If you're into mobile development and want to try to make something updated, please refer to the LHS Self Enrol App (Background details and more info in the blog post from 2012).

Doorbot sounds

Set your wave file (in wav or mp3 format) on the members site. The easiest way of doing this is to have a URL as the filename, and it will stream directly from that URL.

Many early members enjoyed doorbot audio greetings in the style of GLaDOS - an artificial-intelligence sounding voice used in the Portal series of video games and in the movie Pacific Rim. Want to fit in with the 'classical' spirit of the Hackspace? Generate your own GLaDOS voice file on this site here.

Old GLaDOS Voice Generation Guide

(This doesn't work any more, the websites, and videos, that it refers to are no longer active) There was a guide on Youtube made to show the process as its hard to describe simply in text:

The original GLaDOS voices were generated by oni following the method found by Tom Wyatt. To create a GLaDOS voice one must do the following:

  • Go to ATandT's Text to Speech Website (now offline). Type in your name and download the file. Alternately, use Cepstral or another online text-to-speech site allowing downloads.
  • Load up the program Melodyne
  • Select the entire Waveform
  • Using the melodic algorithm, double click on one section of the waveform. I believe this moves the form to its nearest notes.
  • Using the zig Zag looking tool, flatten the pitch.
  • Up the pitch by dragging upwards by 160 or so.
  • Save

Managing Doorbots

Logging & maintenance

If you make changes or discover a problem with doorbot, please add it to the logbook.

On hamming, the listeners are at /srv/doorbot/listeners

sudo supervisorctl restart all