Optical Communication in Free Space - Revision history

Andronicus: /* Receiver */

2011-04-17T03:35:12Z

Receiver

← Older revision		Revision as of 03:35, 17 April 2011
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	==Receiver==		==Receiver==

	A CdS photoresistor seems like the best option.		A CdS photoresistor seems like a good start but probably is not the best option for high data transfer rates.
	http://www.token.com.tw/pdf/resistor/cds-resistor-pgm.pdf		http://www.token.com.tw/pdf/resistor/cds-resistor-pgm.pdf
	Models are available with a spectral peaks at 540 nm or 560 nm. Our green laser pointer emits light at close by at 532 nm for a relative sensitivity between 80 and 90 percent, so the 540 nm models are recommended. It's a nice coincidence that our emission spectrum matches closely to the receiver spectral peak.		Models are available with a spectral peaks at 540 nm or 560 nm. Our green laser pointer emits light at close by at 532 nm for a relative sensitivity between 80 and 90 percent, so the 540 nm models are recommended. It's a nice coincidence that our emission spectrum matches closely to the receiver spectral peak.
	Rise response times are typically 20 or 30 ms and decay response times are typically 30 or 40 ms.		Rise response times are typically 20 or 30 ms and decay response times are typically 30 or 40 ms.

			Photodiode ... add section

	=Legal & Safety=		=Legal & Safety=

Andronicus at 02:04, 9 April 2011

2011-04-09T02:04:51Z

← Older revision		Revision as of 02:04, 9 April 2011
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	*Demonstrate point to point communications across a field with Class IIIa lasers and receiver optics present		*Demonstrate point to point communications across a field with Class IIIa lasers and receiver optics present
	*Determine distance limitations of point to point communications using Class IIIa lasers		*Determine distance limitations of point to point communications using Class IIIa lasers
	*Procure Class IIIb lasers and necessary protective gear and attempt longer range communications		*Procure Class IIIb lasers and necessary protective gear and attempt longer range communications?

	==Data Transfer==		==Data Transfer==
	===Half Duplex===		===Half Duplex===
	*Go/No Go with simple breadboard circuit		*Go/No Go with simple breadboard circuit
	*Simple voice communication ~~with modulator and amplifier circuits~~		*Modulate laser with Arduino pulse width modulation
			*Simple voice communication
	*High speed network communications		*High speed network communications
	===Full Duplex===		===Full Duplex===
	*Go/No Go with simple breadboard circuit		*Go/No Go with simple breadboard circuit
	*Simple voice communication ~~with modulator and amplifier circuits~~		*Simple voice communication
	*High speed network communications		*High speed network communications

	=Optics=		=Optics=
	==Transmitter==		==Transmitter==
	~~=== LEDs ===~~
	~~LEDs have been demonstrated~~

	=== Lasers ===		=== Lasers ===
	The potential advantage of using a commercial laser pointer over over an optically enhanced LED is the lack of the additional optics assembly.		The potential advantage of using a commercial laser pointer over over an optically enhanced LED is the lack of the additional optics assembly. Commercial beam divergences are such that over similar ranges to RONJA project the laser has a smaller spot diameter.
			''
			*Calculate intensity difference at distance between RONJA project and a commercial laser pointer with Gaussian beam equation http://en.wikipedia.org/wiki/Gaussian_beam

	A 5 mW green laser pointer is available from http://www.optotronics.com/green-laser-pointers.php with very good beam properties		A 5 mW green laser pointer is available from http://www.optotronics.com/green-laser-pointers.php with very good beam properties
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	''		''
	*Add equations for divergence and maybe wolfram alpha application for calculations''		*Add equations for divergence and maybe wolfram alpha application for calculations''
	''
	*Calculate power density and compare with RONJA results''

	==Receiver==		==Receiver==

Andronicus at 16:18, 7 April 2011

2011-04-07T16:18:12Z

← Older revision		Revision as of 16:18, 7 April 2011
Line 36:		Line 36:

	==Receiver==		==Receiver==

			A CdS photoresistor seems like the best option.
			http://www.token.com.tw/pdf/resistor/cds-resistor-pgm.pdf
			Models are available with a spectral peaks at 540 nm or 560 nm. Our green laser pointer emits light at close by at 532 nm for a relative sensitivity between 80 and 90 percent, so the 540 nm models are recommended. It's a nice coincidence that our emission spectrum matches closely to the receiver spectral peak.
			Rise response times are typically 20 or 30 ms and decay response times are typically 30 or 40 ms.

	=Legal & Safety=		=Legal & Safety=

Andronicus: /* External Links */

2011-04-03T20:44:56Z

External Links

← Older revision		Revision as of 20:44, 3 April 2011
Line 49:		Line 49:

	=External Links=		=External Links=
	~~Ronja~~ Project http://ronja.twibright.com/		RONJA (Reasonable Optical Near Joint Access) Project Homepage http://ronja.twibright.com/

			http://en.wikipedia.org/wiki/RONJA

	http://members.misty.com/don/laserfaq.htm		http://members.misty.com/don/laserfaq.htm

Andronicus: /* Transmitter */

2011-04-03T20:42:29Z

Transmitter

← Older revision		Revision as of 20:42, 3 April 2011
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	=Optics=		=Optics=
	==Transmitter==		==Transmitter==
			=== LEDs ===
			LEDs have been demonstrated

	=== Lasers ===		=== Lasers ===
			The potential advantage of using a commercial laser pointer over over an optically enhanced LED is the lack of the additional optics assembly.

	A 5 mW green laser pointer is available from http://www.optotronics.com/green-laser-pointers.php with very good beam properties		A 5 mW green laser pointer is available from http://www.optotronics.com/green-laser-pointers.php with very good beam properties
	Beam divergence: <1.2 mrad		Beam divergence: <1.2 mrad
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	''		''
	*Add equations for divergence and maybe wolfram alpha application for calculations''		*Add equations for divergence and maybe wolfram alpha application for calculations''
			''
	~~=== LEDs ===~~		*Calculate power density and compare with RONJA results''

	==Receiver==		==Receiver==

Andronicus: /* Range */

2011-04-03T20:36:16Z

Range

← Older revision		Revision as of 20:36, 3 April 2011
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	=Milestones=		=Milestones=
	==Range==		==Range==
	*Demonstrate point to point communications across a room with Class IIIa lasers and no optics		*Demonstrate point to point communications across a room with Class IIIa lasers and no receiver optics
	*Demonstrate point to point communications across a field with Class IIIa lasers and optics present		*Demonstrate point to point communications across a field with Class IIIa lasers and receiver optics present
	*Determine distance limitations of point to point communications using Class IIIa lasers		*Determine distance limitations of point to point communications using Class IIIa lasers
	*Procure Class IIIb lasers and necessary protective gear and attempt longer range communications		*Procure Class IIIb lasers and necessary protective gear and attempt longer range communications

	==Data Transfer==		==Data Transfer==
	===Half Duplex===		===Half Duplex===

Andronicus at 20:30, 3 April 2011

2011-04-03T20:30:59Z

← Older revision		Revision as of 20:30, 3 April 2011
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	==Receiver==		==Receiver==

	=Safety ~~& Legal~~=		=Legal & Safety=
	Code of Federal Regulations Title 21 Section 1040 [http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=1040.10]		Code of Federal Regulations Title 21 Section 1040 [http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=1040.10]

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	ANSI Z136.6 (2005) - Safe Use Of Lasers Outdoors		ANSI Z136.6 (2005) - Safe Use Of Lasers Outdoors

			http://en.wikipedia.org/wiki/Laser_safety

	=External Links=		=External Links=
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	http://captain.haddock.8m.com/laser/laser1.html		http://captain.haddock.8m.com/laser/laser1.html

			http://en.wikipedia.org/wiki/Free-space_optical_communication

Andronicus at 20:22, 3 April 2011

2011-04-03T20:22:18Z

← Older revision		Revision as of 20:22, 3 April 2011
Line 30:		Line 30:

	==Receiver==		==Receiver==

			=Safety & Legal=
			Code of Federal Regulations Title 21 Section 1040 [http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=1040.10]

			OSHA Technical Manual Section III Chapter 6 Laser Hazards [http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_6.html]

			ANSI Z136.1 (2007) - Safe Use of Lasers

			ANSI Z136.6 (2005) - Safe Use Of Lasers Outdoors

	=External Links=		=External Links=

Andronicus: /* Data Transfer Rate */

2011-04-03T19:33:42Z

Data Transfer Rate

← Older revision		Revision as of 19:33, 3 April 2011
Line 8:		Line 8:
	*Determine distance limitations of point to point communications using Class IIIa lasers		*Determine distance limitations of point to point communications using Class IIIa lasers
	*Procure Class IIIb lasers and necessary protective gear and attempt longer range communications		*Procure Class IIIb lasers and necessary protective gear and attempt longer range communications
	==Data Transfer ~~Rate~~==		==Data Transfer==
	===Half Duplex===		===Half Duplex===
	*Go/No Go with simple breadboard circuit		*Go/No Go with simple breadboard circuit

Andronicus: Created page with "=Overview= Forum Link http://www.knoxvillehackerspace.com/phpbb/viewtopic.php?f=6&t=13 =Milestones= ==Range== *Demonstrate point to point communications across a room with Class..."

2011-04-03T19:29:30Z

Created page with "=Overview= Forum Link http://www.knoxvillehackerspace.com/phpbb/viewtopic.php?f=6&t=13 =Milestones= ==Range== *Demonstrate point to point communications across a room with Class..."

New page

=Overview=
Forum Link http://www.knoxvillehackerspace.com/phpbb/viewtopic.php?f=6&t=13

=Milestones=
==Range==
*Demonstrate point to point communications across a room with Class IIIa lasers and no optics
*Demonstrate point to point communications across a field with Class IIIa lasers and optics present
*Determine distance limitations of point to point communications using Class IIIa lasers
*Procure Class IIIb lasers and necessary protective gear and attempt longer range communications
==Data Transfer Rate==
===Half Duplex===
*Go/No Go with simple breadboard circuit
*Simple voice communication with modulator and amplifier circuits
*High speed network communications
===Full Duplex===
*Go/No Go with simple breadboard circuit
*Simple voice communication with modulator and amplifier circuits
*High speed network communications

=Optics=
==Transmitter==
=== Lasers ===
A 5 mW green laser pointer is available from http://www.optotronics.com/green-laser-pointers.php with very good beam properties
Beam divergence: <1.2 mrad
Beam diameter: <1.5 mm
''
*Add equations for divergence and maybe wolfram alpha application for calculations''

=== LEDs ===

==Receiver==

=External Links=
Ronja Project http://ronja.twibright.com/

http://members.misty.com/don/laserfaq.htm

http://www.repairfaq.org/sam/laserdps.htm

http://captain.haddock.8m.com/laser/laser1.html