Tech:Optical bell - Revision history

Mirwi: Typo fix in explanation.

2018-04-03T03:11:56Z

Typo fix in explanation.

← Older revision		Revision as of 03:11, 3 April 2018
Line 3:		Line 3:
	[[File:Optoring_schem.png\|center\|schematic]]		[[File:Optoring_schem.png\|center\|schematic]]

	The circuit is shown in the schematic above. The diode D2 rectifies the positive portion of the input ringing voltage and charges up the capacitor C3. Of course the negative portion could have been used equivalently, with the diode in correct polarity connected to the negative side of C3. The maximum peak voltage observed at C3, with heavy cranking at a field phone, was about 150V. As a second stage, the capacitor C1 is now "slowly" charged form C3 trough the resistor R1. Voltage at C3 will rise until the base voltage of Q1, generated from C3 voltage through the divider formed by R2 and (R3+R8), is high enough to make Q1 conduct and turn on M1. The moment M1 turns on, there is a significant amount of current that starts flowing through the LED D1 and R8. The now present voltage drop over R8 will additionally feed the base of Q1 and ensures that it stays conducting until the LED current has subsided. C1 will quickly discharge into the LED, making it flash very briefly, for about 2ms, but with high brightness. When C1 voltage has fallen and the LED current has also decreased, Q1 is no longer conducting and M1 also will ~~returne~~ to non conducting mode. As long as there is still charge in C3, C1 is again charged up via R1 and the next led flash is initiated. The time required for C1 charge up will increase with falling C3 voltage. This results in a continuously slowing down flashing of the LED.		The circuit is shown in the schematic above. The diode D2 rectifies the positive portion of the input ringing voltage and charges up the capacitor C3. Of course the negative portion could have been used equivalently, with the diode in correct polarity connected to the negative side of C3. The maximum peak voltage observed at C3, with heavy cranking at a field phone, was about 150V. As a second stage, the capacitor C1 is now "slowly" charged form C3 trough the resistor R1. Voltage at C1 will rise until the base voltage of Q1, generated from C1 voltage through the divider formed by R2 and (R3+R8), is high enough to make Q1 conduct and turn on M1. The moment M1 turns on, there is a significant amount of current that starts flowing through the LED D1 and R8. The now present voltage drop over R8 will additionally feed the base of Q1 and ensures that it stays conducting until the LED current has subsided. C1 will quickly discharge into the LED, making it flash very briefly, for about 2ms, but with high brightness. When C1 voltage has fallen and the LED current has also decreased, Q1 is no longer conducting and M1 also will return to non conducting mode. As long as there is still enough charge in C3, C1 is again charged up via R1 and the next led flash is initiated. The time required for C1 charge up will increase with falling C3 voltage. This results in a continuously slowing down flashing of the LED.
	[[File:opotring_sim_full.png\|600px\|center\|simulation]] <br />		[[File:opotring_sim_full.png\|600px\|center\|simulation]] <br />
	[[File:opotring_sim_blitz.png\|600px\|center\|simulation - single LED flash]]		[[File:opotring_sim_blitz.png\|600px\|center\|simulation - single LED flash]]

Mirwi: Image of hw added.

2017-01-15T15:37:46Z

Image of hw added.

← Older revision		Revision as of 15:37, 15 January 2017
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	The measurement results of the actual built units match pretty well with the simulation. The voltage across R8 is perfectly suited for monitoring the LED current with an oscilloscope...		The measurement results of the actual built units match pretty well with the simulation. The voltage across R8 is perfectly suited for monitoring the LED current with an oscilloscope...

	[[File:hw_optical_bell.jpg\|center\|Hardware build of the optic bell circuit.]]		[[File:hw_optical_bell.jpg\|600px\|center\|Hardware build of the optic bell circuit.]]

Mirwi at 15:33, 15 January 2017

2017-01-15T15:33:51Z

← Older revision		Revision as of 15:33, 15 January 2017
Line 10:		Line 10:

	The measurement results of the actual built units match pretty well with the simulation. The voltage across R8 is perfectly suited for monitoring the LED current with an oscilloscope...		The measurement results of the actual built units match pretty well with the simulation. The voltage across R8 is perfectly suited for monitoring the LED current with an oscilloscope...

			[[File:hw_optical_bell.jpg\|center\|Hardware build of the optic bell circuit.]]

PhilmacFLy at 12:27, 6 January 2017

2017-01-06T12:27:40Z

← Older revision		Revision as of 12:27, 6 January 2017
Line 1:		Line 1:
	~~== Opitcal bell ==~~

	At the [[Events:GPN16\|GPN16]] the plan was to put field phones in all lecture halls, close to the speaker desks. To be allowed to do so, the requirement was that these phones should not disturb any lectures by loud ringing. So the phones were silenced (TODO: link to description) and equipped with the optical ring indicator described below, before deployment.		At the [[Events:GPN16\|GPN16]] the plan was to put field phones in all lecture halls, close to the speaker desks. To be allowed to do so, the requirement was that these phones should not disturb any lectures by loud ringing. So the phones were silenced (TODO: link to description) and equipped with the optical ring indicator described below, before deployment.

PhilmacFLy: PhilmacFLy moved page Tech:Opitcal bell to Tech:Optical bell

2017-01-06T12:26:32Z

PhilmacFLy moved page Tech:Opitcal bell to Tech:Optical bell

← Older revision		Revision as of 12:26, 6 January 2017
(No difference)

PhilmacFLy: PhilmacFLy moved page Tech chaos optoring to Tech:Opitcal bell

2017-01-06T12:24:27Z

PhilmacFLy moved page Tech chaos optoring to Tech:Opitcal bell

← Older revision		Revision as of 12:24, 6 January 2017
(No difference)

Mirwi at 16:25, 4 January 2017

2017-01-04T16:25:58Z

← Older revision		Revision as of 16:25, 4 January 2017
Line 5:		Line 5:
	[[File:Optoring_schem.png\|center\|schematic]]		[[File:Optoring_schem.png\|center\|schematic]]

	The circuit is shown in the schematic above. The diode D2 rectifies the positive portion of the input ringing voltage and charges up the capacitor C3. Of course the negative portion could have been used equivalently, with the diode in correct polarity connected to the negative side of C3. The maximum peak voltage observed at C3, with heavy cranking at a field phone, was about 150V. As a second stage, the capacitor C1 is now slowly charged form C3 trough the resistor R1. Voltage at C3 will rise until the base voltage of Q1, generated from C3 voltage through the divider formed by R2 and (R3+R8), is high enough to make Q1 conduct and turn on M1. The moment M1 turns on, there is a significant amount of current that starts flowing through the LED D1 and R8. The now present voltage drop over R8 will additionally feed the base of Q1 and ensures that it stays conducting until the LED current has subsided. C1 will quickly discharge into the LED, making it flash very briefly, for about 2ms, but with high brightness. When C1 voltage has fallen and the LED current has also decreased, Q1 is no longer conducting and M1 also will ~~have returned~~ to non conducting mode. As long as there is still charge in C3, C1 is again charged up via R1 and the next led flash is initiated. The time required for C1 charge up will increase with falling C3 voltage. This results in a continuously slowing down flashing of the LED.		The circuit is shown in the schematic above. The diode D2 rectifies the positive portion of the input ringing voltage and charges up the capacitor C3. Of course the negative portion could have been used equivalently, with the diode in correct polarity connected to the negative side of C3. The maximum peak voltage observed at C3, with heavy cranking at a field phone, was about 150V. As a second stage, the capacitor C1 is now "slowly" charged form C3 trough the resistor R1. Voltage at C3 will rise until the base voltage of Q1, generated from C3 voltage through the divider formed by R2 and (R3+R8), is high enough to make Q1 conduct and turn on M1. The moment M1 turns on, there is a significant amount of current that starts flowing through the LED D1 and R8. The now present voltage drop over R8 will additionally feed the base of Q1 and ensures that it stays conducting until the LED current has subsided. C1 will quickly discharge into the LED, making it flash very briefly, for about 2ms, but with high brightness. When C1 voltage has fallen and the LED current has also decreased, Q1 is no longer conducting and M1 also will returne to non conducting mode. As long as there is still charge in C3, C1 is again charged up via R1 and the next led flash is initiated. The time required for C1 charge up will increase with falling C3 voltage. This results in a continuously slowing down flashing of the LED.
	[[File:opotring_sim_full.png\|~~thumb~~\|simulation]]		[[File:opotring_sim_full.png\|600px\|center\|simulation]] <br />
	[[File:opotring_sim_blitz.png\|~~thumb~~\|simulation - single LED flash]]		[[File:opotring_sim_blitz.png\|600px\|center\|simulation - single LED flash]]

	The whole circuit is simulated using LTSpice. The results are shown in the two graphs above. On complete one, where the LED slow down is nicely visible, and a zoom of a single LED flash, where the decrease of C1 voltage ~~can be seen~~.		The whole circuit is simulated using LTSpice. The results are shown in the two graphs above. On complete one, where the LED slow down is nicely visible, and a zoom of a single LED flash, where the rapid decrease of LED (D1) current becomes obvious.

			The measurement results of the actual built units match pretty well with the simulation. The voltage across R8 is perfectly suited for monitoring the LED current with an oscilloscope...

Mirwi: Created page with "== Opitcal bell == At the GPN16 the plan was to put field phones in all lecture halls, close to the speaker desks. To be allowed to do so, the requirement wa..."

2017-01-04T00:17:56Z

Created page with "== Opitcal bell == At the GPN16 the plan was to put field phones in all lecture halls, close to the speaker desks. To be allowed to do so, the requirement wa..."

New page

== Opitcal bell ==

At the [[Events:GPN16|GPN16]] the plan was to put field phones in all lecture halls, close to the speaker desks. To be allowed to do so, the requirement was that these phones should not disturb any lectures by loud ringing. So the phones were silenced (TODO: link to description) and equipped with the optical ring indicator described below, before deployment.

[[File:Optoring_schem.png|center|schematic]]

The circuit is shown in the schematic above. The diode D2 rectifies the positive portion of the input ringing voltage and charges up the capacitor C3. Of course the negative portion could have been used equivalently, with the diode in correct polarity connected to the negative side of C3. The maximum peak voltage observed at C3, with heavy cranking at a field phone, was about 150V. As a second stage, the capacitor C1 is now slowly charged form C3 trough the resistor R1. Voltage at C3 will rise until the base voltage of Q1, generated from C3 voltage through the divider formed by R2 and (R3+R8), is high enough to make Q1 conduct and turn on M1. The moment M1 turns on, there is a significant amount of current that starts flowing through the LED D1 and R8. The now present voltage drop over R8 will additionally feed the base of Q1 and ensures that it stays conducting until the LED current has subsided. C1 will quickly discharge into the LED, making it flash very briefly, for about 2ms, but with high brightness. When C1 voltage has fallen and the LED current has also decreased, Q1 is no longer conducting and M1 also will have returned to non conducting mode. As long as there is still charge in C3, C1 is again charged up via R1 and the next led flash is initiated. The time required for C1 charge up will increase with falling C3 voltage. This results in a continuously slowing down flashing of the LED.
[[File:opotring_sim_full.png|thumb|simulation]]
[[File:opotring_sim_blitz.png|thumb|simulation - single LED flash]]

The whole circuit is simulated using LTSpice. The results are shown in the two graphs above. On complete one, where the LED slow down is nicely visible, and a zoom of a single LED flash, where the decrease of C1 voltage can be seen.