Wireless Sciatic Nerve Stimulator

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Wireless Sciatic Nerve Stimulator

• Design Alternatives
• Team 3
• Tom Richner
• Anne Wilson
• Justin Horowitz

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Need
Why wireless?

• Why stimulate?

Multiple surgeries, infection, forces and torques
on nerve
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Design Requirements

• Physical Requirements
• Have a nerve conduit
• Contain a sieve electrode
• Lifetime gt 1 year
• Electrode count 8
• L 5-10 mm
• d 2 mm
• t 2 mm

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More Design Requirements

• Electrical Requirements
• Stimulation
• 0-20 µA per channel
• 0-40 Hz
• Control
• Individual electrode addressing
• At least 4 bit intensity control

• Safety Requirements
• Electrical
• Saturation lt 3 Volts
• Biocompatible

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Power Source

• Lithium batteries (non recharable)
• Rechargeable lithium ion batteries
• Biofuel cells use enzymes mounted on electrodes
  to strip electrons from H, creating H2O in the
  process
• Thermopiles convert thermal potential energy into
  electrical potential energy
• Inductively coupled RF coils transmit power on a
  carrier signal
• Coupling coefficient
• Strength of RF magnetic field

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Power Source
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Electrode Material

• Gold
• Iridium oxide
• Platinum
• Silver-silver cloride
• Monophasic waveform
• Biphasic waveform

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Electrode Material
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Control of Stimulus Amplitude Current orVoltage
Control

• Safety
• Electrode break can lead to burns if current
  constant
• Ease of design calculations
• Can easily relate current to field density
• Reliability
• Might hit the rails of voltage that power
  source can provide

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V control vs. I control
-
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Nerve Conduit Material
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Signal Considerations
Transmission
Signal
Decoding
Encoding
Control Circuitry
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Current Schedule
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Responsibilities

• Justin
• SPICE simulations.
• Anne
• Contact manufacturers, negotiate costs.
• Tom
• Find non-circuit materials.
• All
• Aggressively pool information and analyze SPICE
  results.