Neurostimulation Wearable Device

This is one of the many medically innovative projects that we have worked on. It is named as Transcranial Direct Current Simulation system (TDCS) and is a non-invasive experimental system developed for neuro-psychiatric clinical trial analysis. Though the project did not involve a market-ready product anywhere, yet we helped the client with a proof-of-concept system that would help him demonstrate the patented research algorithm and perform initial clinical trials to analyze treatment performance.

Aim of the Project

We were specifically aimed at creating a simulation system that delivers current in a fixed pattern via connected electrodes. It was supposed to be an LCD based proof of concept system that provides GUI for configuring parameter entries. It was also expected to be capable of churning out statistical data during an active analytical procedure. Lastly, it was meant to be a smart system that could sense any unhealthy or uncomfortable condition being caused to the patient and abort the treatment with immediate effect.

The Challenge

Like any other smart medical device, this simulator needed to show optimum accuracy, precision and real-time execution. These three ingrained demands made the project a challenge in itself.


  • Beagle bone (TI AM 335x processor) black platform
  • 4.3” LCD module with resistive touch screen interface
  • High precision design for Analog section to achieve the performance target of 0.1mA
  • The close loop feedback system to deliver the required level of current accuracy
  • ESD protection to reduce the current spike in the test output
  • Automatic report generation of treatment
  • Protection from excess current in device
  • Power to the user to modify default treatment settings
  • High precision Pattern generation for patient treatment


We helped in prototyping the product. Our team developed the stimulation process as per the patented algorithm porting on the TI AM335x processor. The Close loop feedback in the system monitored the delivered current and adjusted the same in reference to desired current. We used non DAC based Analog Interface Design (using a TI OPA1612 OpAmp) to achieve time critical accurate performance of low current delivery. The experimental system also offers predefined profiles that can help in conducting clinical trials for specific symptoms. Following list shows our contribution in depth:

  • Concept to Prototype to Product development. Creation of Detailed system architecture design based on patent paper
  • Proof-of-concept design using an off-the-shelf processor (TI Beagle Bone Black) and LCD module boards
  • Design and developed custom analog interface design based on the system performance requirement
  • Complete software development with a close loop feedback path based output tuning
  • Feasibility Study for hardware platform selection, Cost v/s Feature tradeoffs, BOM finalization
  • ADC and DAC Linux device driver interface with SPI protocol
  • System timer integration with ADC and DAC using Linux drivers
  • System validation testing
  • Creation of the easy to use GUI with Qt App
  • Unique support of firmware upgrade through Ethernet
  • Complete design of hardware and board bring up
  • Creation of shell script for retrieval of treatment logs files through Ethernet
  • Regression testing, functional testing, system testing, black box testing, white box testing