Department of Electrical and Computer Engineering SDP team Yngvesson Ioan Tihenea Tomas Broka Dmitriy Stupak Sergey Derivolkov IR Communication Channel Supplemental SWNT Component

Department of Electrical and Computer Engineering Design Overview For our Senior Design Project we were working on creating a communication system that has two computer interface terminals and hardware circuitry components on each end and an Infrared communication channel (transceiver) in the center. The key component to our SDP project was a Single Walled Carbon Nanotube (SWNT) thin film detector detecting IR radiation. Due to technical issues, the SWNT thin film detector will be simulated with a photosensitive diode.

Department of Electrical and Computer Engineering System Overview

Department of Electrical and Computer Engineering What happened to the SWNT Thin Film  Idea/Theory  Materials Budget Constraints  Process First Attempts Using Different Carbon Nanotubes Wider Holes on Devices Following the Literature  Challenges Quality of Film Survival of the Acetone Bath

Department of Electrical and Computer Engineering Circuitry and Program Aspects Program  The Logic of the Program  Transmitter End MCU  Receiver End MCU Circuitry  Transmitter Circuitry  Receiver Circuitry Multiple Stage Amplifiers Flexibility of Design

Department of Electrical and Computer Engineering

Signal analysis  Using a multimeter we detected a signal in a range of 0.3 mV to 0.6 mV.  When a film that was detecting a signal in the above range was put on our breadboard, we were not able to detect any signal, the oscilloscope would show only noise.  We shielded the board also used a battery to eliminate 60 Hz noise but signal still couldn’t be detected.  The performance of our circuit couldn’t be determined.

Department of Electrical and Computer Engineering Signal analysis cont.  Replaced the film with a photodiode and the signal could be detected easily.  Using an active probe we were able to detect a signal of 2mV (in a distance of 200cm between IR LED and the photodiode at a frequency of 500 Hz).

Department of Electrical and Computer Engineering Signal analysis cont.  Using a passive probe, to measure the signal from our circuit (photodiode connected to amplifier) the lowest signal peak to peak to be detected was 1.6 mV.

Department of Electrical and Computer Engineering Signal to noise ratio (S/N)  S/N is 1.3.  S/N needs to be higher than 3 for the circuit to work properly.  We conclude that our signal need to be higher than 5 mV to be detected by our circuit.

Department of Electrical and Computer Engineering Demo Demo Presentation

Department of Electrical and Computer Engineering Questions ?