The Energy Directors Jeremy Nash, Chris Lamb, Kelsey Whitesell, Josh Chircus.
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Transcript of The Energy Directors Jeremy Nash, Chris Lamb, Kelsey Whitesell, Josh Chircus.
The Energy Directors
Jeremy Nash, Chris Lamb, Kelsey Whitesell, Josh Chircus
Create a free-space laser communication system capable of: Functioning in a high noise environment Encryption for secure transmission Transmitting multiple signals
simultaneously Long-range, line-of-sight communication
JEREMY
Applications: Military communications Space communications High bandwidth applications
Advantages: Fast (high bandwidth) Lack of interference with other signals Secure (directed) JEREM
Y
Low Priority Transmits digital audio and plays back audio
successfully (one-way) over 1 ft Performs well in high noise environment Encryption
Medium Time division multiplexing (TDM) 2 way communication Alignment feedback system at beginning of/during
transmission Long distance transmission (>10 ft)
High Video transmission and raw data (digital) Continuous automatic alignment including beam
splitter/Quad-Detector feedback JEREMY
* For tw0-way communication, this same system will be mirrored and
addedJEREMY
JEREMY
Alignment system
Packaged Transceiver Units
Two-way communication
Tripods
Bracket and motorized stages
clamp
Inside the package
Laser and photodiode on optical mounts
PCB clamp
front
Side view
power ground
Back view
Transceiver Unit Detail
Need short processing time to avoid long delays in transmission
Need line-of-sightMechanical stabilityLaser beam attenuation constrainedCostManpowerNeed spacing between laser beams
for two-way communication JEREMY
Environmental impact Hard to dispose of parts Beam doesn’t interfere with the
environment because it’s directed energy at optical frequency (no FCC regulation yet)
Safety Laser can damage eye Low power laser (Class IIIa)
CHRIS
● Class IIIa (continuous wave, 1 to 5 mW)● Visible Wavelengths (350 – 800 nm)● Low power/area (typically < 2 mW/cm2)● Corneal damage only (safe viewing time is
0.25 seconds)● Damage includes non-permanent retinal
damage if viewed for 1 or 2 seconds, permanent retinal damage if viewed longer than a few seconds
● Translated: Don't look into the laser (duh).
CHRIS
Manufacturability Photodiode needs to be accurate Motors need to be high resolution
Sustainability Low power consumption Resilient parts and reliable processors Easy to fix because its relatively
straight-forward to troubleshootCHRIS
CHRIS
Signal Source(s): one or more current/voltage signal source(s), for example the output from an iPod
Analog to Digital Converter: Allows for encryption of analog signal
Encryption: performed by encoding data from signal source with a standard encryption algorithm, implemented on a MCU
Laser diode: output depends on current input, so the laser diode itself is an AM modulator
Optics: Optical systems could include the following: Neutral density filters and mirrors to simulate longer distances in the lab Spatial filters and collimating lenses to improve signal quality
Demodulator: at the receiver; this will consist of a photodiode to detect the optical signal and turn it into an electrical signal
Decryption: also implemented on an MCU Digital to Analog: Allows for playback of decrypted analog
signal Output: signal could be output to a speaker for playing a sound,
to a computer to display the received signal, etc. CHRIS
CHRIS
MCU – Comm
MotorsMCU – Motor
Mux De-Mux
Hardware Encoder
Laser Photodiode
Transimpedance Amplifier
Alignment Status
Align comman
d
Motor control
Power Requirements Laser: 5 V DC/3 A = 15W MCU on PCB (x2 per transceiver = 4 total): 5
V DC /1.6 A= 8W Transimpedance amplifier: currently
unknown, will measurePower Supply
OTS power supply for each system ▪ AC/DC converter from wall to DC, probably 15V for
rail powerCHRIS
WDM TDM
Less coding – combination and synchronization done through hardware
Can accommodate modulation at high data rates
1 wavelength per channel Sometimes requires optical 3R regeneration (re-amplify, re-shaping, re-timing)
Requires more lasers/diodes Combination of signal channels is done within the software before it is even sent to the laser to be transmitted
Works better for fiber optics system, since the channels are combined into the fiber upon transmission and demuxed from it after being received
Often requires synchronization with start/stop signals, as well as error channels
For non fiber system, requires lots of space and optical combination equipment (i.e. prism) to achieve combination and transmission as well as demuxing
KELSEY
Four Quadrant Detector
Camera system Neither
Small area (requires approximate alignment by eye)
Small area (requires approximate alignment by eye)
Guess and check alignment, but with limited accuracy
More expensive More complex processing
No additional complexity
TxLaser Beam
Beam Splitter
Focusing lens
Four Quadrant Detector
Rx
KELSEY
Photodiodes-Thorlabs FDS100 350 - 1100 nm High Responsivity in red (635 nm) range Fast recovery time (35MHz)
Laser Diodes from Edmund Optics Built-in safety circuitry▪ Maintains functionality▪ Prevents back-current▪ Provides some temperature control
Max 5mW power (class 3a laser) 635 nm (red) center wavelength Narrow bandwidth (± 10 nm) Low current draw Modulation bandwidth 6Hz-2MHz KELSE
Y
Components to simulate additional distance due to limited lab space Neutral Density (ND) filters for
attenuation Mirrors
Beam Splitter Focusing lens If necessary: lenses for improving
quality and/or collimating KELSEY
Filtering noiseADC/DACMotor Control for alignmentEncryption/DecryptionSwitching between modes of
operation Audio, Raw Data Transfer, and Video
options KELSEY
Turn on laser
Alignment Procedure
Optics
ADC, Encryption, signal modulated
onto the laser
DAC
Noise filtering
OutputKELSEY
KELSEY
Input Signal
Input Signal with DC Offset
Digital Signal After ADC
Example Sample
Example Transmit-Ready Signal
MSP430 xxx series 8-16MHz ADC/DAC options Up to 64 GPIO options Up to 120kB of RAM Ultra-low power usage
JOSH
Motorized track actuators for lateral translations
Stepper Motor for tilt adjustment Plastic packaging for transceiver circuits and
components Stands (possibly tripod) Clamps and Brackets for securing transceiver units Various Mounts (can be machined, if need be)JOSH
Task Primary Secondary
Optoelectric Circuitry Chris Kelsey
Mechanical Structure/Alignment
Josh/Chris Jeremy
Microcontroller (Communication)
Jeremy Josh/Chris
Microcontroller (Motor Control)
Kelsey Jeremy
Board Layout/Construction Jeremy Chris/Kelsey
Digital Signal Processing Josh Kelsey
Design Documentation Kelsey Chris/Josh/Jeremy JOSH
JOSH
Equipment Purpose Estimated Price
Laser Diodes Transmits encoded information $670Photodiodes Detects laser signal $60
Microcontroller Processes signal (see CPU tasks) $50PCB parts
(board, resistors, etc.)
Decodes voltage from photodiode and filters noise
$50
Motorized Track Actuators
Precision adjustment of photodiodes and lasers for automatic alignment
$340
4 Quadrant Sensor
Used in alignment system $500
Lenses Used in alignment system $100Beam Splitter Used in alignment system $90
Tripods Used for Mounting Transceivers $100TOTAL $2300
JOSH
DEPS Funding (Granted) $2200 all purpose funding Requires a report upon completion
UROP Funding (Pending) Up to $1000 funding Requires a report upon completion
▪ These grants should be enough to fund our project.
JOSH
Failure to implement automated alignment due to cost of motors or unforeseen mechanical issues. Mitigate by finding low-cost motors and seeking
advice from mechanical engineer. Failure to implement video transmission due
to insufficient time. Budget time effectively and seek advice for video
transmission requirements. If a rock gets into the system:
There is no possible mitigation – all members perform Hari Kari.
Chris loses energy – not possible. JOSH