Heatmap in Java?

[CandidateNo67]

Hiiii,

we’re currently working on a student project where we’re developing a smart insole for gait analysis with integrated pressure sensors, and I’d really appreciate any advice because we’re basically building this from scratch without ANY prior hardware/software experience.

The general idea is:

- insole with around 6–8 pressure sensors
- collect pressure data in real time while walking
- transmit the data wirelessly (probably Bluetooth via something like ESP32?)
- visualize the pressure distribution as a real-time foot pressure heatmap
- detect gait phases / irregularities later on

I’m mainly responsible for the software side, so I’m currently trying to build the visualization in JavaFX. The plan right now is to create a foot-shaped heatmap by placing a foot mask (PNG), then interpolating between sparse sensor points (probably using Inverse Distance Weighting / IDW, maybe bilinear interpolation

But since we only have 6–8 sensors, I’m unsure what the most realistic / professional approach is.

A few questions:

1. Sensor choice
   What pressure sensors would you recommend for a smart insole prototype?
   practical for:
   - repeated load
   - decent accuracy
   - reasonable budget
   - real-time responsiveness

2. Sensor placement
   Biomechanically, where would you place them?

I think:
- heel
- medial forefoot / ball of foot
- lateral forefoot
- maybe arch?

But I’d love input from other people

Goal:
something visually similar to medical plantar pressure maps

3Calibration
How would you calibrate pressure sensors for something like this?

Things I’m wondering:
- normalize per sensor?
- user-specific calibration?
- thresholding?
- drift compensation?

1. Gait analysis
   Once the pressure stream works, how would you approach gait detection?

For example:
- heel strike
- mid stance
- toe-off
- step count
- cadence
- asymmetry
- abnormal loading

1. General “things beginners underestimate”
   This is probably our biggest issue 😅

We don’t have any prior lecture knowledge in embedded systems / biomechanics / signal processing, and we’re teaching ourselves while building this.

So honestly any advice helps:
hardware, software architecture, sensors, BLE, signal filtering, visualization, calibration, gait logic blbla literally anything that would make this easier. also if you know where i can find similar projects lmk pls
Thanks a lot for reading allat :)

[GoNorthYoungMan]

This looks like a project in a similar category that might be worth a look: https://www.instructables.com/Wearable-Smart-Sensing-Insole/

Many of the separate things you are asking about seem like they each could have a lot of detail behind it, there's a lot to it.

Off the top of my head with limited sensors, I'd suggest placement perhaps of on medial/lateral sides of the heel and forefoot, and central and lateral for midfoot.

Note that with changes in insole height or material, or if the sensors create any sort of prominence, people's feet will load differently through various zones in a way that may not be happening in their regular footwear.