BicycleLighting - Revision history

Rachel: /* next step */

2009-01-16T05:10:55Z

next step

← Older revision		Revision as of 22:10, 15 January 2009
Line 66:		Line 66:

	=== next step ===		=== next step ===
	~~Still need transistor circuit as all the LEDs together will~~ be ~~more current than the op amp can handle.~~ ~~That is the last piece of circuit~~.		Big(?) capacitor behind seat switch s/b sufficient to keep lights on for some time after seat is vacated. How big must it be? Test.

	~~Big(?) capacitor behind seat switch s/b sufficient~~ to ~~keep lights on~~ for ~~some time after seat is vacated~~. ~~How big must it be?~~		Alternately, I have a scribbled diagram that uses a Schmitt trigger which is claimed to be usable for this purpose... research & poke at this more.

	I can create the seat cover with embedded pressure switch whenever, it's just a switch, so it can wait until last.		I can create the seat cover with embedded pressure switch whenever, it's just a switch, so it can wait until last.

Rachel: /* current state */

2009-01-16T04:29:45Z

current state

← Older revision		Revision as of 21:29, 15 January 2009
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	blue pot ranges from 0 ohms to about 2.35k ohms. the pair of leads swap resistance levels compared to the single lead, such that the total resistance is always about 2.35k ohms. When the pot is turned all the way to one side, resistance between the single lead and one of the doubles is 0, and from the single lead to the other of the doubles is 2.35. When it's turned all the way to the other side, the resistances on the double leads, against the single lead, is swapped.		blue pot ranges from 0 ohms to about 2.35k ohms. the pair of leads swap resistance levels compared to the single lead, such that the total resistance is always about 2.35k ohms. When the pot is turned all the way to one side, resistance between the single lead and one of the doubles is 0, and from the single lead to the other of the doubles is 2.35. When it's turned all the way to the other side, the resistances on the double leads, against the single lead, is swapped.

			Have the 2 circuit bits combined with a transistor, fully functional. Drew circuit diagram & breadboarded additional version from diagram to test diagram; made a couple small corrections. Diagram is correct (possible resistor values s/b changed for optimality as NB supply hadn't anything smaller than 100 ohm).

	=== next step ===		=== next step ===

Rachel: /* current state */

2008-12-17T20:48:57Z

current state

← Older revision		Revision as of 13:48, 17 December 2008
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	Learned a bit of comparator chip circuit theory from David... Have the op amp circuit breadboarded out such that it turns on one LED when the photoresistor is occluded. Circuit includes a pot for calibration, forming the second voltage divider.		Learned a bit of comparator chip circuit theory from David... Have the op amp circuit breadboarded out such that it turns on one LED when the photoresistor is occluded. Circuit includes a pot for calibration, forming the second voltage divider.

			Notes on my pots:

			blue pot ranges from 0 ohms to about 2.35k ohms. the pair of leads swap resistance levels compared to the single lead, such that the total resistance is always about 2.35k ohms. When the pot is turned all the way to one side, resistance between the single lead and one of the doubles is 0, and from the single lead to the other of the doubles is 2.35. When it's turned all the way to the other side, the resistances on the double leads, against the single lead, is swapped.

	=== next step ===		=== next step ===

Rachel: /* next step */

2008-12-03T06:25:30Z

next step

← Older revision		Revision as of 23:25, 2 December 2008
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	=== next step ===		=== next step ===
	~~Update breadboarded comparator circuit to use potentiometer for calibration. Take it to light & dark places & mess with it.~~

	Still need transistor circuit as all the LEDs together will be more current than the op amp can handle. That is the last piece of circuit.		Still need transistor circuit as all the LEDs together will be more current than the op amp can handle. That is the last piece of circuit.

Rachel: /* current state */

2008-12-03T06:25:06Z

current state

← Older revision		Revision as of 23:25, 2 December 2008
Line 57:		Line 57:
	The photoresistor registers about 140k ohms in inside natural light, held under the bike seat. In the bathroom with the door mostly shut, simulating nighttime, it registers 22M. Tentative initial ON value: 20Mohm.		The photoresistor registers about 140k ohms in inside natural light, held under the bike seat. In the bathroom with the door mostly shut, simulating nighttime, it registers 22M. Tentative initial ON value: 20Mohm.

	Learned a bit of comparator chip circuit theory from David... Have the op amp circuit breadboarded out such that it turns on one LED when the photoresistor is occluded.		Learned a bit of comparator chip circuit theory from David... Have the op amp circuit breadboarded out such that it turns on one LED when the photoresistor is occluded. Circuit includes a pot for calibration, forming the second voltage divider.

	=== next step ===		=== next step ===

Rachel: /* next step */

2008-12-02T07:13:55Z

next step

← Older revision		Revision as of 00:13, 2 December 2008
Line 60:		Line 60:

	=== next step ===		=== next step ===
	~~Breadboard out this~~ comparator circuit ~~using a pair of voltage dividers (one with photoresistor, one with~~ potentiometer for calibration).		Update breadboarded comparator circuit to use potentiometer for calibration. Take it to light & dark places & mess with it.

			Still need transistor circuit as all the LEDs together will be more current than the op amp can handle. That is the last piece of circuit.

			Big(?) capacitor behind seat switch s/b sufficient to keep lights on for some time after seat is vacated. How big must it be?

	I can create the seat cover with embedded pressure switch whenever, it's just a switch, so it can wait until last.		I can create the seat cover with embedded pressure switch whenever, it's just a switch, so it can wait until last.

Rachel: /* current state */

2008-12-02T07:08:36Z

current state

← Older revision		Revision as of 00:08, 2 December 2008
Line 57:		Line 57:
	The photoresistor registers about 140k ohms in inside natural light, held under the bike seat. In the bathroom with the door mostly shut, simulating nighttime, it registers 22M. Tentative initial ON value: 20Mohm.		The photoresistor registers about 140k ohms in inside natural light, held under the bike seat. In the bathroom with the door mostly shut, simulating nighttime, it registers 22M. Tentative initial ON value: 20Mohm.

	Learned a bit of comparator chip circuit theory from David...		Learned a bit of comparator chip circuit theory from David... Have the op amp circuit breadboarded out such that it turns on one LED when the photoresistor is occluded.

	=== next step ===		=== next step ===

SpammerHellDontDelete: /* next step */

2008-12-01T01:22:25Z

next step

← Older revision		Revision as of 18:22, 30 November 2008
Line 60:		Line 60:

	=== next step ===		=== next step ===
	Breadboard out this comparator circuit using a pair of voltage dividers (one with photoresistor, one with ~~dialled variable resistor~~ for calibration).		Breadboard out this comparator circuit using a pair of voltage dividers (one with photoresistor, one with potentiometer for calibration).

	I can create the seat cover with embedded pressure switch whenever, it's just a switch, so it can wait until last.		I can create the seat cover with embedded pressure switch whenever, it's just a switch, so it can wait until last.

SpammerHellDontDelete: /* parts */

2008-12-01T01:22:08Z

parts

← Older revision		Revision as of 18:22, 30 November 2008
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	* 1x LM393 (op amp) analog comparator for voltages		* 1x LM393 (op amp) analog comparator for voltages
	* 1x photoresistor		* 1x photoresistor
			* 1x pot
	* various resistors & capacitors to produce the right 555 outputs		* various resistors & capacitors to produce the right 555 outputs
	* 1x fabric pressure sensor		* 1x fabric pressure sensor

SpammerHellDontDelete: /* next step */

2008-12-01T01:20:57Z

next step

← Older revision		Revision as of 18:20, 30 November 2008
Line 59:		Line 59:

	=== next step ===		=== next step ===
	~~Figure~~ out ~~how to translate the~~ photoresistor~~'s output into an ON/OFF signal~~. ~~Surely I don't need a microcontroller for this!~~		Breadboard out this comparator circuit using a pair of voltage dividers (one with photoresistor, one with dialled variable resistor for calibration).

	I can create the seat cover with embedded pressure switch whenever, it's just a switch, so it can wait until last.		I can create the seat cover with embedded pressure switch whenever, it's just a switch, so it can wait until last.