Multitool Alarm System

Here’s a way to make sure you don’t leave your Leatherman multitool somewhere. It’s an alarm system that will start a timer when the tool is removed from the holster. After five minutes the module beeps to remind you to put the tool back where it belongs. Annoying? Possibly, but if you’re not done with your work just press the reed leaf switch on the module to reset the timer. A PIC 12F683 handles the timing and generates the waveform for the piezo buzzer. Perhaps this could have been accomplished with a dual 555 chip like the LM556 (one timer for the countdown and another for the piezo waveform) but the PIC has power-down modes available that should make the button batteries last a long time.

44 thoughts on “Multitool Alarm System

  1. I was doing lighting for a Student Union Party at my old University and I let one of my crew use my leather-man (passed down from my father) and when he was done, he left it next to where he was working, in the middle of campus. it was gone for less than 5 minutes before it was truly gone.

  2. You could even get away with one 555…
    Maybe using a large cap or resistor to create a long pulse and then a few transistors to make a latch to switch it for a much smaller value for the alarm sound when the tool is replaced it just cuts the power for a reset (:

  3. perhaps I’m showing my ignorance here, but I suspect “just push the reed switch” would only be an easy task for Magneto, particularly when the device hasn’t got a reed switch…

  4. What you on about PIC taking advantage of lower power saving mode?

    have the timer circuit simply wait 5 minutes from power on then start noise. When the read switch is pressed in, cut power from the battery. I am fairly sure no power at all is more efficient then very little power.

    I also would say that a dual 555 circuit would be much more suitable here. spec when you consider you can get two 555 in one IC. pair of trim pots could be used nicely to change the delay and pitch of noise.

  5. @Olestra
    Indeed, I’d call that a microswitch, not a reed switch :) second time here in a couple of days.

    Unless a sleeping while counting pic uses less power than a 555, not much power saved here (as long as the switch cuts the power to the whole circuit as here.

    Could be done with a cap resistor high gain transistor latch and a self oscillating buzzer too!

    There’s no beating the component count of the original though!
    The pic might be immune to delay drift due to battery discharge, too !

  6. 555/556 + NC Microswitch. When the multitool is in the case, the switch is depressed, opening the circuit so no battery usage at all. The circuit will only run while the multitool is in use.

    0ma is less drain than >0ma even in powersave mode for a pic.

  7. Or you could just tie it to your buckle with a piece of piano wire. I know, no electronics involved, how dare I? And some will say that the wire can be cut with the pliers! Well, to be honest, if people are desperate to nick your Leatherman, they could just beat you up, and electronics won’t help (albeit the buzzer could help the cops find your corpse if the battery lasts long enough).
    Seriously, do we have to have electronics hooked up to everything, even if it really doesn’t need any? I’m surprised noone submitted an electronic device to pull down your zipper when you pop to the loo. Too scared to have a rogue spark injury maybe?

  8. For those who don’t see the need for this haven’t employed people. I rarely forget mine as I have painstaking cut a spot in my tool box for each one. However, my employees… I am lucky if I can go a week without replacing something. They will leave it out in the weather, leave it then forget, or I am not sure what else they might come up with. I might need to build one of these for every tool they might use.

  9. @ vonskippy: You said what I was thinking, even if it came off a little harsh.

    I have the holster, and that’s where it goes.
    I have yet to misplace one in 25 years of using them.

    That being said I think this still shows merit, however it should really be built into the holster!
    Really thin along the back or sides would work.

    You could make it an after market clip-on if you really worked at shrinking it down.

  10. @Davo1111

    That’ll work until they figure out that the leatherman has wire cutters and just cut the piano wire!

    but I agree with your first point. If you don’t want to lose it don’t give it out.

  11. @tom, yeah i see your point. But it will keep a semi honest man out :P

    I’ve seen a similar method used to stop communal keys from going missing. Get a chain, and a very large block of wood (connect the wood to the key with the chain). That way the key can’t be used without lugging around a piece of wood. Very hard to keep in your pocket. :)

  12. I thought the point was to remind you to put it back. I have been on job sites where people will use about 100 tools in half and hour of work with many times not putting them up till the job is done. A reminder would be nice. Also, maybe he just uses to keep track of time and not get lost in projects. I doubt it was to stop someone from stealing it.

  13. @BadCoding then the decision becomes: shall I return these 100 tools, or jam one in the speaker/electronics and fix it that way? :)
    I’m (half) joking but I do get very testy when I try to fix things and it doesn’t go too well.

  14. Good Lord I never understood in reading HaD I was in the company of so many individuals that achieved perfection. Then again they may routinely loose tools as well, and are afraid to admit it to even themselves. Hell I have never been that proud, so this is a clever idea, I saved it for future reference.

  15. @xeracy
    I have a leatherman passed down from my father also. He never liked to have his picture taken or anything so the only things I have to remember him by are the tools I used with him as a child. If anything happened to ANY of them, especially the leatherman I would be devastated. I feel your loss.

  16. I’ve had my fun with 555s for a couple of decades (at least), but it came to the point that they are more expensive than a PIC. That and the fact that the software is easy to write (a much more accurate timer to boot), more flexible (extra pins), no drift, etc. Add the low parts count and I stopped using the 555s for timers or anything square wave related a long time ago (including blinking LEDs)

    BTW, this is a waste of a 683. It can be done with much smaller/cheaper PICs (10F200, 12F508, etc)

  17. @rofl mcwaffle

    I just saw the bit in the blurb about power saving.
    So then if the case has a power cutoff switch, wth kinda power saving does Mike think a pic would realistically achieve?

  18. Nice to see the interest in this little circuit.

    Just to address some of the points raised (all of them perfectly valid, b.t.w.):

    “It could have been done with 555’s/discrete components.” Indeed, but as some people have already pointed out, it would have meant a more complicated and bulky circuit, and would probably be more expensive to boot.

    “It could have been done with a cheaper PIC.” Oh yes, the ‘683 was just what I had handy. If I were to build this in any number I would look for the cheapest PIC I could find that, a) runs of 3V, and b) has an internal oscillator. Not that the 683 is expensive.

    “It could have been done with a piece of piano wire/string.” I tried that method, many years ago, not on a Leatherman but on a simple pocketknife, and found that the string was a constant nuisance, getting in the way, limiting my reach and having to be stuffed away with the knife. Apropos some comments above, this is nevertheless a perfectly valid point. Personally, I love electronics but I’m also a great proponent of the KISS principle.

    “The beeping would be annoying.” Speaking from only a few days of experience yet; mildly so. But mildly doesn’t describe my annoyance at loosing the tool and having to rack my brain to remember where I last used it. You could increase the time between reminders by modifying the source code, if you wanted.

    “It doesn’t provide theft protection.” Perfectly true. This was devised as a defense against my own forgetfulness, not theft.

    “I never loose my Leatherman.” Kudos to you; I just wish I was this organized. Not that I have yet lost my Leatherman completely, but I have had to visit several places I was working at over the last day or two and hunt around for it.

    Power saving issues: That was not the reason I used the PIC; it was the simplicity and compactness of the circuit I was looking for. A 555 circuit may possibly use somewhat less power. Mind you, by far the most power is used by the sounder while beeping, so minor power savings during the 5 minutes pause would be negligible overall.

    Thanks for all the interest :-)

  19. There is a low power version of the 555. Dwino or 555, this on to the next big thing. Our short term memory is egged on by our time. We have too many windows open, too much stuff in the tray. I don’t use multi-tools I use many tools, but I used a flashlight till I lost too many.
    Don’t put tools or torches on your key-ring. An intermittently used tool is as good as gone, when busy.
    I am convinced that RF ID or ex-proximity alarm is the best solution to tool loss. Like a safer police weapon, a flashlight that won’t light up for someone else. Keep it up! All ideas are up for review.
    My hack is a one watt led flashlight running thru a small resistor running off a cell phone adapter. It’s always on and very handy at a fixed location, peering down into electrodepths of hardware. The 22 gauge skinny wire is very long so it can move around well but only in the room.

  20. I like this idea, it’s something that might well have commercial merit, especially for larger things like power drills and entire toolboxes. Indeed, perhaps a crew of electricians that operate out of a van by the roadside… Put a bluetooth (or something more robust and reliable) gizmo in the toolbox and a receiver in the van. When the connection is lost (tools and van separated by a long distance) an alarm goes off in the van to tell the crew they’ve left the tools behind!

    That’s a contrived example but you get what I mean. In fact it seems so obviously useful that it probably has been done already. I bet it’s expensive though.

  21. If I were to modify this circuit it would be to make it small enough to fit into the bottom of the sheath.

    Let’s make that three from Iceland. :) (although I don’t actually live there anymore)

    I really like the project Serkey from Kari. If I could be bothered to build it, me and the 11 other technicians I’m working with could remove the keyboard from our toolboxes. :)

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