WangIxihan
commented
9 months ago PDF manual: BioTac® Product Manual BioTac Website: Robotics & Prosthetics | SynTouch (syntouchinc.com) Patent: 1499065777900190136-US20160025615A1 (storage.googleapis.com)
Sensors in Focus: Impedance Sensing Electrodes As forces are applied to the skin, the skin and fluid deform. Changes in impedance as the fluid deforms are detected by an array of electrodes on the surface of the BioTac core. Hydro-Acoustic Pressure Transducer As objects slide across the surface of the BioTac, they generate vibrations that are detected by the sensor inside the core
Impedance Sensing Electrodes Basis: A voltage divider with 4 common excitation electrodes, sensing electrode, and a reference to a 10kΩ load resistor A 3.3V pulse will be sent from the microcontroller through the excitation electrodes to the sensing electrode
Questions: What are excitation electrodes? Electrodes that receive electrical signals What are the sensing electrodes that are being used and can we source them? A normal sensor (force sensing resistor) Amazon.com : force sensor
Hydro-Acoustic Pressure Transducer: https://www.benthowave.com/ Website contains everything about hydrophone sensors and transducers Hemispheric Transducer is possible, omnidirectional is a candidate Frequency response for the Biotac sensor is 10 - 1040 Hz.
Hall Sensors: sensors that sense magnetic fields. Output voltage is directly proportional to the strength of the magnetic field.
I think we can start building. The pressure sensor seems to be a wheatstone bridge with one variable resistor. Why the pressure sensor is a Wheatstone Bridge: it acts like a balancer, readjusting the variable resistor to accommodate for changes in the detecting resistor.
Circuit Schematic and Parameters: P_DC op amp (fluid pressure): MPX2101A P_AC op amp (micro vibrations):
Mon, Oct 2: Just 2 op-amps to start with. Resistor load is 10k ohms. Literally just electrodes → literally just points of contact for electricity. Flexible Circuit Model pinout is in paragraph below the manual.
Slip and Force Sensor
Bought Hall Sensor Light Sensor (to replace the old phallic-shaped sensors that don’t work)
Before then, I will order some cheap piezoelectric sensors to see if we can set up a circuit using either arduino and raspberry pi
Complete this by the end of the semester. Demonstrate that the piezoelectric sensor somehow works.
Transfer data into arduino IDE. Write up a procedure
11/27/23 Piezoelectric sensors are noisy at detecting blood pressure, so maybe that can be improved with fine tuning. But, I successfully removed the resonant frequency from the air. Instrumentation amplifier Band-pass filter Any more circuit components? Goal for Spring: Shrink my design Test using one finger.
Spring 2024 Goals: Investigate the viability of higher-order Chebyshev filters Analog to digital converter Investigate the viability of incorporating Hall Sensors into our design Shrink and test for one finger.
Analog-Digital Converter: Converts voltage reading into digital reading to be processed in a microcontroller 10-bit IC ADC
https://www.electronics-tutorials.ws/electromagnetism/hall-effect.html ‘Biasing’ magnet for Hall effect