3D Direction Sensor - Question from a Neuroscientist

Question

I'm posting here on the advice of r/diydrones, who said you're the people to ask. I'm hoping you might be able to help out with a problem i've come across in my research?

I'm a Neuroscientist working on spatial cognition. Broadly, i'm looking to find out exactly how the brain represents the space around us, our position in it, and how we move through it. This should lead to a better understanding of diseases in which these processes are affected, such as Alzheimer's, and show us novel ways of treating it. To do this, I use mice and rats, trained to perform spatial tasks, such as navigating mazes.

Specifically, i'm investigating head direction cells. These are neurons which encode the direction which we are facing at any given point, up and down, left or right, etc. I'm looking for a way to record the direction that a mouse or rat is facing in real-time. Systems already exist for recording this, but only in two dimensions, that is to say, they lack the ability to be able to record up/down head movement, or inversion of the animal. Additionally, as they rely on tracking small LEDs, these systems can't be used in complex 3D mazes, as the lights are not always visible.

I initially asked r/diydrones for suggestions of electronic methods of tracking head direction in 3D. The best suggestion appeared to be using the ICM-20948.

There are two problems with this that i'm trying to work through. The first is physical. I need to implement this chip in a way which is minimally invasive for the rat/mouse. That means that whatever processor and power source i use needs to be as small and light as possible. Ideally, it would be wireless. Using wired power and data transmission is definitely workable, but does have limitations.

The second problem is that I need to be able to synchronise the motion/direction data very closely to brain recordings which are being made simultaneously. Currently, this is fed as an analogue signal directly to a recording PC.

As someone with very limited coding and electrical engineering experience, the inclusion of any guide materials you know of along with any suggestions would be very much appreciated.

Please do come forward with any comments, suggestions, or questions.

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Thanks

Answer 1

It's clearly possible to do so with a gyro sensor and a blackbox. Take for instance micro quadcopter, those have full fledged flight controller with processor, gyro, blackbox, OSD, ESCs, accellerometer etc... all in one 20x20mm PCB! I mean you could design your own PCB with just gyro, processor and blackbox (perhaps recording on a micro SD). I think the resulting PCB wouldn't exceed 10x10mm which shouldn't bother the rat too much. If you mind taking this advice into consideration take a look at the following link to check Drone Mesh Open Hardware project: http://dronemeshforum.com/viewtopic.php?f=37&t=5375&sid=a9f8c001e412814a4679909f96ca8cae

The rat could be equipped with the gyro on top of an helmet wired on a micro lipo battery attached on his back. The blackbox would track everything coming from the gyro along with a timestamp to syncronize data once you'll extract it...

Or you can buy a device as the one shown in the following link and ask the producer to help you: https://youtu.be/tyiuocPvUes