Andy's Solar-bugs

B.E.A.M.
BEAM is an acronym standing for :
Biology, Electronics, Aesthetics and Mechanics
last updated Mar 27, 2007

DIY : "Dark" Detector

Parts list :

solar-panel : Panasonic 2433	NEC 0.047F, 5.5V Gold caps	red fled
47K resistor *	NPN 2N3904 transistor	5mm photo-transistor
Optional Powerstor 1.5F supercaps

* ( 22K, 33K, 47K and 100K Ohms resistors are included in Kit#7 to play with sensitivity)

6 items for a "Dark" detector. Not bad at all.
If you use battery to replace solar-panel and capacitor, that will be 5 items all together !!

Tutorial May 13, 2002
Test drive the circuit on Breadboard Feb. 8, 2002

	3J connected to +ve with jumper wire 6J connected to -ve with jumper wire I'll explain it later
	spread the legs of the 2N3904 a bit so it will fit into the sockets of the breadboard
	6F : E of 2N3904 5F : B of 2N3904 4F : C of 2N3904
	6G : E of photo-transistor (longer leg) 5G : C of photo-transistor (shorter leg)
	4G : Cathode of fled (shorter leg) 3G : Anode of fled (longer leg)
	3H : 1 leg of 100K ohms resistor 5H : the other leg of 100K ohms resistor To turn on the fled at "Complete Darkness", use 100K ohms resistor lower the value of the resistor to adjust the sensitivity, ie, 47K, 33K, 22K
	Hook up the battery : +ve to +ve, and -ve to -ve. When I cast a shadow onto the photo-trnasistor, the red fled is on !!
Mega-easy, eh :-)

Tutorial May 13, 2002
Here's the pics :-) 26 Nov., 2001



	General layout of the 'dark" detector. I'm going to put it close to my window, so the photo-transistor should point to the outside and the fled should point toward me.
cast a shadow onto the photo-transistor, the fled starts to blink
darker the shadow, brighter the blinker :-)

Tutorial May 13, 2002

Basic concept :

The common use of photo-transistor is light trigger, ie, light shined onto the photo-transistor will activate the circuit. Thus, the "Light" detector.	What if we want to turn on a fled when light is out ? A nocturnal circuit.
Basic circuit used here is to have the Vo "low" when light is shined onto the photo-transistor. :-)
The "load" can be fled, flag spinning motor or anything you can think of.
Simple enough to do it yourself :-)
Parts I used instead: · solar-panel : Panasonic 2433 panel · capacitor : NEC 0.047F, 5.5V Gold caps · photo-transistor : 5mm p-transistor with deep blue casing (daylight filter) · resistor : 100K resistor · transistor : NPN 2N3904 transistor · load : red fled
More pics are coming. Not today, need more time to rest :-(	Nov. 18, 2001, Nov. 23, 2001, Nov. 26, 2001