Card Reader Lockout Keeps Unauthorized Tool Users At Bay

It’s a problem common to every hackerspace, university machine shop, or even the home shops of parents with serious control issues: how do you make sure that only trained personnel are running the machines? There are all kinds of ways to tackle the problem, but why not throw a little tech at it with something like this magnetic card-reader machine lockout?

[OnyxEpoch] does not reveal which of the above categories he falls into, if any, but we’ll go out on a limb and guess that it’s a hackerspace because it would work really well in such an environment. Built into a sturdy steel enclosure, the guts are pretty simple — an Arduino Uno with shields for USB, an SD card, and a data logger, along with an LCD display and various buttons and switches. The heart of the thing is a USB magnetic card reader, mounted to the front of the enclosure.

To unlock the machine, a user swipes his or her card, and if an administrator has previously added them to the list, a relay powers the tool up. There’s a key switch for local override, of course, and an administrative mode for programming at the point of use. Tool use is logged by date, time, and user, which should make it easy to identify mess-makers and other scofflaws.

We find it impressively complete, but imagine having a session timeout in the middle of a machine operation would be annoying at the least, and potentially dangerous at worst. Maybe the solution is a very visible alert as the timeout approaches — a cherry top would do the trick!

There’s more reading if you’re one seeking good ideas for hackerspace. We’ve covered the basics of hackerspace safety before, as well as insurance for hackerspaces.

19 thoughts on “Card Reader Lockout Keeps Unauthorized Tool Users At Bay

  1. The workday ends at 5:00PM and cleanup starts at 4:30PM plenty of time to ensure the projects have come to an end and no one is using the tools. This is installed in a scene shop (read- shop that builds scenery for theatre) at a university that sticks to scheduled hours. Certainly, a good point to make if others wish to create something similar for their space – cutting a tool off mid process could be hazardous (usually just annoying when you are talking about woodworking tools).
    This device controls a multi-pole contactor that disconnects our major tools from power (Band saw, table saw, radial arm saw, jointer, planer, panel saw, drill press, etc). It is a pretty slick upgrade and allows us to stop making copies for lost keys.
    Great work, OnyxEpoch.

  2. Every machine tool I’ve ever seen and the few I own have an isolation switch that can be locked in the off position with a small padlock, as far as I can remember this has been standard practice since the late 60s or possibly the early 70s, this early safety feature comes across as way more hacky than the featured “solution” to a non existent problem.
    I apologise for the negativity, I just detest overly complicated and unreliable solutions to simple problems, especially when the simple solution is in place and has been for fifty years.

    1. +1

      Also, a mag strip in a hacker maker place? Hmmm…
      I’ve worked in many shops and managed many, this has never been an issue.

      Is it a neat project? Yes, it is, but not a good application to show it off, just my two cents

      1. The shop is a thorough fare for a couple classrooms and is unable to be completely locked. Shutting off the power is the only way to prevent the tools from being used in the off hours. Sure we could go around nightly and lockout each individual tool… or we can disable them all at once with this device.
        The author choose mag strips because that’s what’s on the student ID cards. The goal was to not issue any kind of key (rfid or otherwise) and to use something the students already had.
        Just to comment on the complexity- the author created this as part of a Controls class. The challenge was to improve a system we already had in place. He achieved this and left the manual key switch (that used to be the means of controlling the contactor). So if there is ever an issue the key switch can always be used to switch things on our off just like it has for years.

        1. This device is electrically unsafe, does not adhere to NEC or NFPA79 rules in obviously dangerous ways, and seriously increases the risk to students’ lives. I’m questioning the ability of the supervisor too if he/she believes that it is safe enough to put into operation, and the competence of the facility management too if they allowed it.

    2. The padlock on the main switch is still the only reliable way to keep a machine powered off which also makes insurance companies and work safety inspectors happy.
      I designed a similar system to track machine usage some years ago, using a Dallas “Silicon Serial Number” (DS2401) mounted in a 6.35mm phone plug. Simple operation, plug inserted = machine on, plug removed = machine off; the unique serial number was used for access control and billing.

      1. Perhaps because they also do it in a way that are certified by UL to be in compliance with the NEC, something that might matter when the insurance company declines to cover the lawsuit resulting from someone getting electrocuted by this deathtrap. I’m no NEC or NFPA79 expect, but off the top of my head I can see:

        1. No ground on a metal enclosure containing 120V
        2. No ground bonding to the cover on a hinged enclosure.
        3. I cannot see where the 120V passes through the enclosure, but I’d bet you $20 right now that it does not do so in a UL-listed manner.
        4. Poor wiring safety generally, including 120V wires in a position where they could get trapped leading to an energized enclosure.
        5. Relay isn’t correctly rated for power tools, nor as a safety-rated disconnect.
        6. LED is an incorrect color. (Green or Red acceptable here, depending on whether you are indicating “tool power” (green) or “Operator risk” (red)). Blue has a specific meaning (Mandatory action required)
        7. Off button is an incorrect color. Red preferred, black, gray, white permitted.
        8. No ESTOP.

        Saving a couple of hundred bucks whilst spending some hours scratching a hobby itch is all well and good if you can do somewhat safely, but this is a great example of what NOT to do. The arduino stuff is cool, but the electrical safety demonstrated is *grossly* incompetent.

  3. I think it would have been better with some sort of key that has to stay in for the machine to work. That way you’re sure that it doesn’t stop in the middle of something important. And since you would need the key for the other machines it would keep people from leaving it in all the time.

    1. But it will not stop people losing their keys all the time. RFID for entry (and other) control systems is one of the best inventions ever in my opinion.
      I worked in quite a few places with mechanical locking systems and at least once a year every lock and key hat to be replaced/remade (couple of thousand bucks) because some idiot lost his bag/coat/whatever with the keys and the address in it.
      With RFID you can just erase the Tag in the system and you’re done.

  4. Rather than a time out while the machine is running, why not a countdown to timeout that starts once the machine is turned off? 30 seconds or so would probably sufficient for most things where all you’ve got to do is reposition a vise or jig. I could see how it may be inconvenient for more complex tasks, though less inconvenient than slamming tooling into moving material because the arduino says the shop is now closed.

    Apart from keeping the reader clean spoofing magstripe data is fairly trivial. Though if your shop has people hacking into things they shouldn’t be, it sounds like you’ve got other issues to deal with.

  5. In response to the timer running out during a cut safety issue, a second contactor in parallel with the controller, with the coil powered by the the machine switch. While it is running if the timer ends it will keep running. Release the trigger and the contactor drops out requiring the timer to be reset to reuse the machine.

  6. This could also be a pretty good way of measuring/limiting/monetizing usage in terms of running hours per user per tool so you can also have a breakdown of who uses what for how long.

    I have two criticisms/suggestions:
    1)I don’t see a big red safety button. It needs an obvious shutdown method.
    2)That the Arduino is directly controlling the relay. If the Arduino output fails ON, the machine fails on. Instead, maybe have the arduino energize an enable signal, then have the button use that enable to energize the contactor which seals ON.

    Not big things and honestly, not something that I remember ever being brought up in my controls class. You develop fail-safe thinking on the job mostly.

  7. Magnetic card reader without a pin code (or any other form of personal authentication) at a _Hacker_ space – there was probably an exploit of that thing on the first day

  8. Wow, can’t believe all the negativity. Let’s look at the use case for this, shall we?
    – A makerspace that has several hundred members.
    – Members come and go
    – Not all have taken the training
    – Only those trained can use the equipment.
    – This is not a commercial shop where all the people are your employees. This is a shared use community space. Of friendly people. (NOTE:A “hacker space” doesn’t mean people are hacking into things. Just another way of saying people that use creativity to do out of the box kids of things. @chris Sokup, @JSON)
    @John Blackthorne and every other person who cried too complex for a simple task – Keys are expensive and hard to manage. (@Hank Hall – we agree) RFID can be easily removed from a database for any of a number of reasons (misuse of equipment, membership status, tool training, hours of use per month reached).

    – @Conrad – I like the dual contactor idea, but most places don’t have a hard cutoff for time, so let’s leave that one for now.
    – @Leithoa – As an alternative a 30 second countdown with a beeper would be helpful. Nice idea.

    – Big RED EMERGENCY Switch. @Jay Lowe
    – Um. the Arduino just supplies power to the device. It doesn’t turn on the device. The saw/planer/sander has its own switch. You are simply cutting off the wall power to the device. If that device was pulled out of the box and plugged into a wall, it would have the same safety features as the scan for access device. So….

    @ID – Some good ideas here, but overshadowed by some serious flaws and logic leaps.
    – There is a power cord going in, but it powers the 12v powersupply for the internal components.
    – I do see the relay for the power, but I don’t see the 120v wires that it controls, Could even be mounted on the back of the enclosure.
    – The system is NOT the safety disconnect. As above it is simply there to switch wall power.

    @Paul Kelly – Net time you feel generous enough to donate $50,000 to a volunteer run, cahritable makerspace, you let me know. We’d be happy to take your check. In the meantime, we can afford the $5.00 Arduino, and $20.00 of components bought or stripped from discarded equipment.

    Thanks for all your support people. Nice work.

    Major Kudos to OnyxEpoch for not only building it, but sharing it with all of us. I’m sure there was one or two items in here that could help improve Gen 2.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.