Personal Compass Points to Your Spawn Point

A conventional compass points north (well, to magnetic north, anyway). [Videoschmideo]  wanted to make a compass that pointed somewhere specific. In particular, the compass — a wedding gift — was to point to a park where the newlywed couple got engaged. Like waking up in a fresh new Minecraft world, this is their spawn point and now they can always find their way back from the wilderness.

The device uses an Arduino, a GPS module, a compass, and a servo motor. Being a wedding gift, it also needs to meet certain aesthetic sensibilities. The device is in an attractive wooden box and uses stylish brass gears. The gears allow the servo motor to turn more than 360 degrees (and the software limits the rotation to 360 degrees). You can see a video of the device in operation, below.

The compass module may be hard to find, but you should be able to modify it to work with more readily available boards. Since you may not be able to find the exact gears used, your build will probably be a little different anyway.

The brass and wood are decidedly steampunk looking. It reminded us of this GPS project. If you have too much street cred to buy an off-the-shelf GPS, you could always roll your own.

22 thoughts on “Personal Compass Points to Your Spawn Point

  1. well cute idea but the box is huge can you at least put anything in it? it takes an age to boot up, that led kind of ruins the aesthetic. there are accelerometers that sit in low power sleep until moved, perhaps that could replace the button and make it a little more magical. is the hand and gears just going to sit on the lid like that? seems fragile. servo and gears didn’t really work out for continuous rotation, clearly a modified servo or even stepper with continuous rotation feedback would have been better suited.

      1. ‘Twas ever thus. The eternal conflict between artists and critics…

        In this case, the critic’s comments are spot on from the standpoint of making a “better” compass of the heart, but they do not detract at all from the wonderful, almost magical ingenuity of the basic idea.

      2. ok you are right, I will never again suggest any possible improvement to absolutely anything until I have done it myself from scratch. I am so embarrassed who the hell did I think I was I am so ashamed. to the builder please take off your trousers so everyone can suck you off indefinitely with no regard to its actual value or quality. also HAD please alter the “thoughts on” to “praise for” because clearly that’s all that anyone should ever post.

          1. -You- read it as dismissive of the build. I didn’t read it in that way at all. I still don’t, even after going back and reading it a couple more times.

    1. Sure the design could have many kind of improvements no matter how he made it.
      Practically I do not think that during it’s lifetime it will ever be used more the a few times, just to see if it works and that’s it. And I’m sure the builder is very aware of that.

      The idea behind it is very nice and that’s what counts for this build.
      I’m sure that this is one of the most original gifts at the party.
      so I would say, well done.

    2. The author also clearly states that it his first adventure with an arduino or the majority of the priciples at work. I also would bet that he made it on a short timeline.

      Instead of being a douche and criticizing it, why don’t you offer constructive criticism and help them improve.

      To reiterate: Don’t be a douche.

      1. I think you need to relearn the meaning of constructive criticism. Read from Wikipedia:
        “Constructive criticism is the process of offering valid and well-reasoned opinions about the work of others, usually involving both positive and negative comments, in a friendly manner rather than an oppositional one.”

        Oh and did you even read parent’s post? He does provide a well-reasoned opinion involving both positive and negative feedback! He does point out it is cute and has aesthetic, points out some things he doesn’t like and suggests several ways it could be improved.

        To reiterate: Instead of attacking parent’s comment with an il-formed and off-topic comment, why don’t you make yourself useful and actually reply to his personal remarks and suggestions? He does have a point in that the led ruins aesthetic and that the gears on top are put in a fragile situation. I disagree with the use of an accelerometer, it would be much cheaper to use two tilt sensors mounted orthogonally. His remark on using a stepper motor is also a good idea.

      1. Let’s think of the impossible for a second. Could a small amount of ferrofluid in a round tube under the compass neddle change where it points to?

        And could that ferrofluid “blob” be placed preciselly with two opossing electric coils around the tube?

        Because, if we can find how to do both of that, then the device would be A) a functioning compass, B) the magic device, C) “solid state” and noiseless.

    1. That’s a great idea! Remagnetizing the needle might take more power than the current version, though (plus, you’d need a mechanism to hold it still while that takes place).
      Maybe you could use separate visible and magnetic needles, connected with some kind of adjustable coupling. The whole thing would have to be light enough for the weak pull of the needle to spin it, though…

    2. Yeah, this is how I’m thinking I might do it – take an existing ornate magnetic compass and leave that functionality intact. Add a rotating ring the circumference of the existing dial (hidden behind the backing of the compass dial) which contains a small magnet (neodymium for strength, if necessary) which is driven by a small DC motor. You could use a rotary encoder to determine the position of the magnet and close the control loop, a small GPS board to pull location periodically, and a cheap accelerometer to track rotation between location polls.

      That way I’d like to think you’d get a nice needle swing as the compass aligns with the magnetic field and the aesthetics are preserved from the original compass, plus you would get less of the mechanical “stepping” or rotation limit of the OP’s design.

      Cool idea, I like it a lot.

    3. Guys, apart from most likely using an electronic compass anyway, the device only needs to store the bearing of the target in internal μC eprom every once in a while. When powered on, it can temporarily use the old value until the gps found a lock.

  2. It’s a great idea, even if the implementation might leave a little to be desired.
    My first improvement idea was to ditch the servo and use the stepper from an automotive gauge. They take very little power, and this is exactly what they were designed to do. You’d have to add some kind of feedback, though. Probably a good idea to also swap out the Arduino for an MSP430 (or even just a smaller, stand-alone AVR) for even lower power usage.

    1. It looks like the needle is fluttering a lot when he goes through the full rotation, sometimes pointing up, other times to the right. This is some kind of overflow or sign error in the code. Also a PID algorithm to handle the mass of the needle would remove the fluttering.

      1. Nah, it has nothing to do with the mass of the needle, rc servos are geared down big time so this mass is not an issue. I haven’t looked at the code, but I am going to say it has more to do with his code and constantly sampling and updating the servo.

  3. It might be fun to hack an old timepiece that has visible internals. The seconds, minutes, and hour hands could all point to different coordinates.

    Walk around with the device, press button/pull lever, and and the hands spin around until they are pointing in their approximate directions.

  4. E. E. ‘Doc’ Smith called that an Object Compass in 1916, and it worked for any object, even on the other side of the universe. But you have to master 4th and 5th order forces and find a source of X metal in order to build one. IIRC, 5th order forces require a neutronium lens fished out of a neutron star and constrained by 4th order forces. You also need steel that has been flashed over into arenak in order to handle the stresses involved in assembling the equipment to make inoson, which is strong enough to hold the neutronium lens. These things must be thought through very carefully.

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