Instructables

Gyrocompass Dead-Reckonator

FeaturedContest Winner
Picture of Gyrocompass Dead-Reckonator
P1020207.JPG
P1020170.JPG
This started out as an attempt to make a Gyrocompass from 3 hard drives; and ended being a Dead Reckoning Navigation Device (keeps pointing at its initial heading).

A gyrocompass is designed to find and point to true north, however in this case I think there is too much friction, and not enough rotational inertia for it to work.

I'll run through the theory and build anyway, and maybe somebody will have a suggestion to get it working? or will be able to build one better!

What it does now, is look really cool, spin up to around 12,000 rpm, and maintain its current heading. Because it maintains its heading while the base is moved, the degree markings can be used to obtain the new heading with respect to the original. In this way it can be used as a dead reckoning navigator. It is also very educational, I already knew theoretically how a gyro worked, but this puts it into perspective a lot better.

What you need:
2 hard drives
Assorted materials to create brackets/gimbals, I used brass and aluminium
Depending on your hard drive circuitry, you may also need a BLDC motor controller.

Equipment required:
Hand tools for dissasembly/assembly (hard drive take torx head screwdriver bits)
Metal working equipment to make brackets and gimbals
 
Remove these adsRemove these ads by Signing Up
Tomohawk2 years ago
Beautiful work! I'm sorry to hear it doesn't work quite as you wanted, but it looks totally amazing!
andrew.spencer.2 (author) 2 years ago
I have since talked to a guy who services shipboard nav gyros, he said the rotors they use on similar RPM units weigh upwards of 10kg, and are larger diameter. So my gyro is probably getting about 5% of the rotational inertia that the commercial units use.
rachel2 years ago
Love this! No idea why it doesn't do what you expected, did you wait for like a day with it running? I'd assume it would need that general range of time to observe the effect, since despite how fast the earth's surface moves, the change of angle with respect to north would go pretty slowly. But I don't really know what I'm talking about, this is just a guess.
andrew.spencer.2 (author)  rachel2 years ago
The article said about 80 minutes for a cycle. The earth rotates at 15 degrees an hour, and applying just a minuscule force (and less than one degree) to the pendulum (to change its orientation as the earths spin would) causes the heading indicator to move. So I would expect the 4 hours I left it going for should have generated some perceivable movement.

But on the plus side, it can hold it's current heading for at least four hours!

Thanks for your comments though.
rimar20002 years ago
Very neat work!
rimar20002 years ago
(removed by author or community request)
Cool beret! are you Scottish?
No, I am Argentine, thanks for the compliment!
Aleator7772 years ago
Amazing work, this is beautiful to look at.
Pro

Get More Out of Instructables

Already have an Account?

close

PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!