[Solved] Can the IMU detect human proximity on hard floors?

I have a family of squirrels that visit my yard most days, and it is clear they are spying on me. How do I know?

The squirrels like to lay, (in the shade), prostrate on the patio. I have discovered that they will turn their heads toward me in two circumstances: 1) I strike up a conversation with my wife (inside the house 30 to 50 feet from the squirrel), or 2) When I walk, (inside the house, barefoot), toward the squirrel 15 to 20 feet away.

My house is built on a concrete slab, which (clearly) transmits vibrations to the squirrels.

I have done some cursory programming to use my robot’s microphone as a sound level proximity sensor using average and peak sound statistics, but was not impressed by my skills with this sensor.

My robot does not have an accelerometer to investigate this use as a proximity sensor.

The IMU’s BNO055 accelerometer spec sheet states 1mg sensitivity in 2g mode with +/-80mg (zero-g) bias.

Is this sensitive enough to detect a human approaching to within 5 feet of a robot sitting quietly on a hard surface flooring of a home?

(My robot sensor philosophy is to maximize usage of as few sensors as possible, because every new sensor is a distraction from the holistic focus I want. The PiCamera is currently my robot’s most sensitive proximity sensor, but is also a resource and power hog, so using a layered proximity sensor approach is beneficial.)

Found this research on footsteps measured at 1 meter - 0.001 to 0.002 g peaks so IMU is probably not useful for footstep detection: https://www.researchgate.net/publication/241517823_Vibration_signature_of_human_footsteps_on_the_ground_and_in_buildings

Honestly, I think theory (or in this case other’s work that hasn’t been validated by your tools) can only take you so far. If I were you, I’d just set up the robot to record from the IMU and start moving around the robot, jump and stuff like this. At the same time, I’d also record myself to be able to match it with the IMU’s data, if it’s applicable.

Next, I’d take the values and plot/process the data. You’ll undoubtedly see if your footsteps are picked up.

If you decide to try this out, let me know too about the results.

Agree, but I have not invested in an IMU and mounting adapter.

(A couple years ago, Element14 had a “Propose a project, get a free RPi 3.” I won one with a speech recognition test proposal. I’ll save this “IMU proximity sensing test” for a “Propose a project, get a free IMU” offer.)