How to Build a North Sensing Device to Improve Your Sense of Direction

2022-07-18 | By ShawnHymel

License: Attribution Compass Magnetic Arduino

Some folks (like me) do not have a great sense of direction. I cannot tell where north is at any given moment (without looking at a compass, map, or the sun). I also lose track of which directions I turned while visiting new environments.

In 2010, Dr. Susan Barry wore a device made by her husband on her hat to help her improve her sense of direction (source: https://www.psychologytoday.com/us/blog/eyes-the-brain/201009/can-you-acquire-sense-direction). The device buzzed whenever she looked north. After a few weeks, she reported having a better sense of direction, at least in the areas she visited while wearing the device.

I repeated Dr. Barry’s experiment to see if it would help my (also terrible) sense of direction.

The rest of this tutorial shows you how to build your own north-sensing device if you would like to repeat the experiment yourself.

Required Hardware

You will need the following electronics:

You will also need some wire to connect everything, a 3D printer to make the case, a lanyard, and a buckle strap.

3D Print the Enclosure

Use a 3D printer to build the files here: https://github.com/ShawnHymel/myoken/tree/main/mechanical

Many thanks to my favorite roboticist and oddity, @Odd_Jayy for creating these CAD files on Fusion 360 for me!

3D printing the Myoken case

Hardware Connections

Connect the electronics as follows. You should not use a breadboard or headers, as the electronics would be too high to fit. Instead, directly connect the pins as shown with wires and solder. Note that you will likely need to bend your switch pins so that it sits at a right angle away from the Feather board (unless you purchased a right-angle switch).

Myoken electronics schematic

Use a hot glue gun to attach all of the electronics inside the enclosure. Make sure that the USB port and switch can be accessed through the holes in the enclosure.

Myoken electronics inside the enclosure

Calibration

Before wearing the device, you will need to calibrate the magnetometer to account for hard- and soft-iron distortions. Hard-iron distortions are caused by permanent magnets near the magnetometer that cause simple additive offsets to the values. Soft-iron distortions are caused by nearby metals (mostly ferrous material, but non-ferrous metals can cause such distortions, too). These distortions will warp the readings multiplicatively.

Make sure that you are in an area away from permanent magnets (like those found in speakers) and other electronics (give at least 3 feet from your computer when calibrating).

Follow the instructions in this tutorial to find the calibration offset values. Upload the Arduino sketch listed in the tutorial to the Feather and open the MotionCal software (downloaded from here). Spin and move the board around to gather a set of samples. This should create a sphere on the visualizer.

Visualizing the magnetometer calibration process

Once you’re done, record the Magnetic Offset (hard-iron calibration values) and Magnetic Mapping (soft-iron calibration values). You’ll need them in the next section.

Additionally, if you wish to use true (geographic) north instead of magnetic north during your experiment, you will need the magnetic declination value for your area. You can obtain that number here: https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml#declination.

Programming

Open the Arduino sketch found here (https://github.com/ShawnHymel/myoken/blob/main/myoken/myoken.ino). Scroll down to find the calibration values. Replace the values with those you copied from MotionCal and the NOAA magnetic declination page (set to 0 if you want to use magnetic north instead of geographic north).

Entering calibration values into the Arduino sketch

Upload the sketch to your Feather board. Hold the harness enclosure vertically and face the front (lid) toward north. You should feel the enclosure vibrate.

The Test

The hypothesis is that you should be able to wear the device for a few weeks to train your body where north is at all times. Here are a few possible reasonings behind this:

You begin paying attention to landmarks (e.g. the sun, certain roads) and associate cardinal directions with them
You pay attention to the directions you turn and learn to keep better track of where north is in relation to your turns
You develop an innate sense of north through magnetoreception

I wore the device for two weeks while conducting my daily activities. Going to work, taking my dog for a walk, etc. I did not wear it during workouts, as I highly doubt it would survive sweat.

Wearing Project Myoken

Conclusions

After wearing the device for 2 weeks, I ran a few tests to see if my sense of direction improved.

First, I tested my sense of north in an area that I frequented while wearing the device. This was easy, as I had learned the landmarks (i.e. street direction) many times during the test phase.

Next, I tested myself in a park that I did not visit while wearing the harness. While I could not discern north from any innate feeling, I could easily look for recognizable landmarks or the sun's location.

Finally, I put myself in a dark room in a new location to test my sense of direction. As before, I was unable to feel any sense of direction innately. Without any recognizable landmarks, I was once again lost.

Testing my sense of direction

While this sample size of one certainly does not prove or disprove any of the hypotheses, I can say that having a wearable device remind you of a cardinal direction will help you pay attention to your surroundings. However, this offers no more benefit than intentionally looking at a compass or a map.

I found that whenever the device would buzz, my eyes and mind would take a snapshot of the various landmarks. As a result, the device helped me learn directions in the confined area where I wore it and forced me to think about my relative position to the sun.

However, it did not provide magical magnetoreception powers. I’m not sure what would happen if I wore it longer. You may have a different experience.

Going Further

Check out these posts if you would like to learn more about improving your sense of direction and magnetoreception: