I present to you : the 7th sense, based on the NorthSense and the Cardinal Compass projects

Hello there !
A few months ago, I got my first implant ever, a titan in my left ringfinger.
Since then, I discovered a passion for body augmentation, and I’ve been looking for ways to enhance the human body in practical ways ( such as adding/enhancing senses, for example, or… this, which is frankly awesome, but not buyable yet )

And then I stumbled upon the NorthSense implant, which sounds awesome, if not for the fact that it sticks out out your chest like a baby xenomorph and is a constant health hazard, then on the Cardinal Compass Wearable project, that sadly didn’t go very far.

So, I decided that since I can’t find any cool augmentation, I’d just make my own !

I’m calling it the “7th sense” for now, but the name is subject to change. The idea is very similar to the Cardinal Compass, with a few changes, and obviously the fact that it’s going to be actually fonctionnal :

  • It only features a single motor, that vibrate in 4 easily understandable patterns, depending on your cardinal orientation.
  • It’s shell is 3D printed in TPU, meaning it’s soft and resilient.
  • It’s attached to a 1mm aluminum plate for rigidity, and it has an aluminum insert that makes it more resilient to pressure
  • The device is made of a main case, and a battery case that can be inserted and locked in, to power it up. The battery case is easily swappeable, and is fairly small and light, meaning it’s easy to carry one or two spares for the day.
  • It automatically start a calibration sequence every time it’s powered up, if it comes within range of a strong enough magnet, or if it detects it’s values have drifted over time.
  • It detects when your arm is downward or horizontal, and adjust what direction it’s supposed to show you. Meaning, if you point a direction, it will show you the appropriate cardinal direction, but if you point down, for example when walking, it will show you the direction facing the front of your wrist.
  • Approximate size is 12x100x50 mm, without the arm strap.

Feel free to comment any idea you could have for improvement, or tell me what you think !


Hello, glad to hear you’re interested in taking this on.

What microcontroller, sensor and batteries are you planning on using?

If you need any help ideating, designing, testing, or fabricating feel free to hit me up.


I’m using an arduino pro micro, the magnetometer is a LIS3MDL, and the accelerometer is a ADXL345. The batteries are generic 3.7V / 1100 mAh batteries that I found on Aliexpress, I believe they should be enough to last a whole day on one or two batteries.

The coding part is almost done for now, unless someone brings up a cool idea / feature to add in !

Also, I’ve already printed a few prototypes for the casings, it’s going pretty smoothly, I think most of the work is done now, but thanks !


Very interesting.
Do you have a few pics of the prototypes?

1 Like

As of now the prototype isn’t fully assembled, meaning the inside is just duct taped to an aluminum plate, and the shell is made of PLA plastic, instead of TPU plastic, but here’s a 3D view of what the shell looks like, as of now

The working version will have the shell attached to a 1mm aluminum plate for rigidity, and a TPU band to fasten it comfortably to the forearm.


Are you planning on making it a public project?
I’d like to make one

A rechargeable battery might be nice :+1:

I may, depending on if I find ways to build more quickly, and if some amount of people are interested.
Also, the batteries are recheareable, of course, I intend to make at least 3 or 4 batteries, with the appropriate casing so they’re easy to swap out quickly.

Who would be interested in purchasing or building a compass wearable?

  • Purchase
  • DIY Build

0 voters


It depends on the form factor and the location where it has to be worn.

I loved the NorthSense idea, with the sensor located on the chest. I loved also the idea to attach it to surface piercing, although I understand it might be difficult to get for a lot of people and also subjected to rejection quite quickly. I don’t like much the Sentero idea, having to wear it on the arm.

Why not wearing on a chest strap, like a Polar or Garmin heart rate monitor. Maybe even by reusing the Polar strap and its attachment points for the sensor ?

1 Like

Maybe some sort of clip would be ideal, so people with boobies could just put it on the bra strap? That would be pretty cool - I don’t like the idea of wearing it on the arm as well…

1 Like

There are sport bras with the strap built-in. You just have to clip your preferred HRM.
Like this one from Polar.

But I like the clip-on idea too, with a strap for men without “moobs” :sweat_smile:

The magnetometer needs to be calibrated relatively often ( probably not more than a couple time a day, once it’s done ), and to do that you need to rotate it in all 3 axis a bunch of times, I don’t think you’d be able to do that if it’s strapped to your chest x)
Though it could be detacheable, but you’d need a secure way to strap it in and not loose it, but also be able to detach it easily for calibration.

Use a calibration free compass module

1 Like

Calibration free ? That sounds weird, I guess it’s more like auto-calibrating ? I don’t know how well it could work, I’ll think about it if I find a way to produce it in larger scale !

1 Like

Just a guess, but calibration is a software issue. A sufficiently sophisticated firmware I’m the sensor could use a low grade accelerometer with magnetic sensor to do its own heuristic calibration over time… basically sensing through movement over time and track the changes to create a kind of “magnetic map”… hell it might be able to do that without the accelerometer… dunno.

Calibration is a problem though so definitely being worked on or apparently has been solved somehow… probably with a more elegant solution than I just conjured up hah :wink:

When I originally skimmed this I misread it as you were making an implant and I got to “battery bought off AliExpress” and was a little concerned. It sounds like a cool project though. I’d be interested in DIYing a version

Ah, well I really hope that it has, and I also hope it’s a bit more elegant than mine, though I suspect it’s not that far from what’s used in most devices ! But if this sensor truly does self-calibrate, it’ll take a sizeable bother off the 7th sense, I’ll have to get a look at it !

I’m not that insane yet, though I would gladly instal a battery under my skin if Amal promised it was safe :ok_hand:

1 Like

100%. He does a great job with sourcing.

There are some very interesting battery chemistries and construction methods being developed for cars that would be amazing as implant cells… nothing commercially available yet though