Controlling a human being with a game controller: it seems crazy, right? You're not dreaming: just two electrodes and a small device can help you take control of the balance of your worst enemies!

The Génialissime Vecteur de Sensations (GVS) is a Galvanic Vestibular Stimulation device built with analog electronics, designed to induce balance and orientation sensations through controlled current stimulation.

Génialissime Vecteur de Sensations

milovan.me

Caution

This device can deliver electrical current to a human skull. By using this project, you agree that you are solely responsible for any accident, dizziness, nausea, or existential crises that may occur. I'm not a doctor: do not use it if you don't know what you're building and doing. Max current is hardware-limited to 5mA, but that's still enough to ruin your afternoon.

Build and use it at your own risk.

🧠 What is GVS?

Check out the detailed documentation.

Galvanic Vestibular Stimulation (GVS) is the process of sending electric messages (in this project, a low-level DC current) to a nerve in the vestibular system, located in the ear, that maintains balance. We "access" the vestibular system through the mastoid process, a conical projection forming a bony prominence behind and below the ear.

Vestibular system

The vestibular system is a sensory organ, constitutive of the inner ear, that creates the sense of balance and spatial orientation for the function of coordinating movement with balance. This organ is present in most mammals.

Troubles of the vestibular system can lead to dizziness: this device exploits this by applying a controlled DC current to the mastoid process, artificially triggering the vestibular nerve and inducing balance and orientation sensations.

⚙️ Circuit Design

Check out the detailed documentation.

The circuit is a transconductance amplifier: it converts an input voltage (the joystick position) into a controlled output current through the electrodes. The core of the circuit is an improved Howland current source, preceded by an input signal generation stage and followed by a push-pull output stage with hardware current limiting.

Signal flow

The signal flows as follows:

1. A stable ±2.5 V supply is generated from the ±9 V rails
2. The joystick position sets a DC bias between -2.5 V and +2.5 V through a potentiometer
3. A fade-in/fade-out RC filter smooths abrupt transitions
4. A Wien oscillator generates a 300 mVp sine wave at 1.5 Hz
5. Both signals are summed and inverted before entering the Howland stage
6. The Howland current source converts the input voltage to a proportional current
7. A push-pull stage boosts output compliance and current capability
8. A hardware current limiter caps the output at 3-5 mA
9. Current flows through the electrodes placed on the mastoid processes

🔒 Safety

Check out the detailed documentation.

This device delivers a controlled electrical current directly to the human skull: this is not a toy! Hardware protections are in place (current limiter, emergency stop), but they are not a substitute for testing, electrode placement, and common sense.

Documentation

Find your happiness:

• 🧠 What is GVS?: Vestibular system, physiological effects and stimulation principles
• ⚙️ Circuit Design: Improved Howland current source, push-pull follower and component selection
• 🔒 Safety: Current limits, galvanic isolation, emergency switch and build protocol
• 🧪 Simulation: LTspice models, transient analysis and scenarios

Repository Structure

├── spice/           # SPICE schematic and simulation files
├── docs/            # Documentation, conception notes
└── assets/          # Images, schematics and illustrations