Inspiration
Topographical disorientation is a condition that can affect anyone, but it is especially prevalent among older adults and individuals with dementia. Losing one’s way, even in familiar surroundings, can lead to distress and potential danger. We set out to design an intuitive navigation aid that works even when visual and auditory cues aren’t practical or effective.
Instead of relying on phone screens, spoken directions, or complex vibration patterns, we wanted a solution that the body could interpret directly, minimizing cognitive load and providing clear, physical guidance.
What it does
Equilibrium is a wearable system that guides a person’s movement using targeted muscle stimulation on the calves. By contracting specific muscles, it gives intuitive cues about which direction to move:
Left calf stimulation – turn left
Right calf stimulation – turn right
Both calves – continue forward
When integrated with GPS through a Bluetooth Low Energy (BLE) module, the system can guide users along a pre-determined path without requiring visual or audio attention.
This approach ensures navigation instructions are immediately understood. There is no memorization of vibration patterns, no looking at a screen, and no reliance on hearing.
While vibration motors are common in wearable navigation aids, they have two major drawbacks:
- Cognitive interpretation: Users must learn and remember what each vibration pattern means. This can be a challenge for those with cognitive impairments.
- Lack of physical guidance: Vibration is passive, it alerts, but doesn’t physically influence movement.
Muscle stimulation overcomes these limitations by producing active, directional movement cues. It reduces cognitive demand because the body feels the motion directly, and it can subtly help initiate steps in the intended direction. This makes it ideal for users who may have memory difficulties, attention issues, or motor challenges. For users with reduced mobility or gait initiation difficulties (common in Parkinson’s), this active assistance can be the difference between standing still and taking a step.
How we built it
Arduino Nano: Core controller handling signal processing and relay activation.
TENS 7000 Relay Unit: Delivers controlled electrical stimulation to calf muscles.
Relay Switch: Safely interfaces the Arduino with the TENS unit.
Optional BLE Module: Enables GPS-based route navigation when paired with a mobile device.
The device is worn as a discreet calf wrap, making it both comfortable and socially unobtrusive.
Challenges we ran into
Early progress was slowed by faulty components, particularly during the testing phase with stimulation hardware.
Calibrating stimulation intensity to be both comfortable and effective required trial and error.
Integrating modular expandability (GPS, geofencing, future IMU features) while keeping the form factor small was a design challenge.
Accomplishments that we're proud of
Developing a fully functional directional muscle stimulation prototype in under 24 hours.
Validating that muscle stimulation is a more intuitive navigation method for certain populations compared to haptic vibration.
Laying the foundation for a multi-purpose wearable that can expand beyond navigation into balance and mobility support.
What we learned
Hardware must be tested early and thoroughly, faulty parts can cause major time loss.
Muscle stimulation requires individual calibration to ensure comfort and safety.
Navigation cues don’t need to be complex to be effective; simple, direct signals are best.
What's next for Equilibrium
GPS Integration via BLE: For complete, route-based navigation.
Geofencing: Alert caregivers if the wearer leaves a designated safe area.
Gait Symmetry Tracking: Detect and correct uneven walking patterns.
Balance Recovery with IMU: Use an Inertial Measurement Unit to detect loss of balance and trigger rapid calf stimulation to help restore stability.
Fall alert: Alert caregivers if a sudden fall is detected
Expanded Muscle Targets: Include hip or thigh stimulation for enhanced mobility assistance.
Miniaturization: Reduce device size for increased comfort and all-day wear. Also make the design more unobtrusive/fashionable.
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