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 :
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solar-panel
: Panasonic 2433 |
NEC
0.047F, 5.5V Gold caps |
red
fled |
|
100K
resistor * |
NPN
2N3904 transistor |
5mm
photo-transistor |
|
Optional
Powerstor 1.5F supercaps |
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* ( 22K,
33K, 47K and 100K Ohms resistors are included in Kit#7 to play with
sensitivity)
6 items for a "Dark" detector.
Wanna give it a try......... :-)
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1a. Small wires are
soldered onto the pads first. |
1b. epoxy is used here
to fix the wires position |
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2a. bend the legs of
2N3904 as above |
2b. soldering the
"brain" |
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3a. this is the
"brain" of the "Dark" detector |
3b. 100K ohm resistor
goto +ve of solar-panel |
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4a. don't forget to bend
the panel wires upward for the capacitor later |
4b. make sure the
"brain" is located closee to the center |
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5a. fled anode (longer
leg) goto 100K ohms resistor |
5b. marking on the
0.047F capacitor is -ve (longer leg), should goto -ve wire of
solar-panel |
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6a. bend the legs like
that |
6b. flip it over to let
it sit on my desk, with the P-trans facing the window. The red fled will
start blinking when the sun is down !! |
Viola, 30 mins later, you got yourself a
"Dark" detector :-)
last
updated Mar. 20, 2002
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Roll of 40 pins IC round
legs socket in 2 rolls, that gives you total of 80 pins :-) Just use your
nippers to cut into the plastic case. |
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solder 2N3904B with 1
pin, and then the +ve solar-panel with the other pin. Crazy glue the pins
onto the panel. Let it set for overnight (I used 5 min crazy glue) |
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You can now plug in the
diff. value of resistor to play with the light sensitivity. Have fun :-) 100K ohms resistors will turn on the
"Dark" detector when it is "completely" dark. 47K ohms resistors will turn on
the "Dark" detector when you cast a shadow on it. 33K ohms resistors will turn on
the "Dark" detector when you cast a "slight" shadow on
it. |
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Hook up the 1.5F Supercaps and the fled will
blink for hours :-) |
Back to more pics on
"Dark" detector
Basic concept :
Circuits quoted from :
http://www.engr.udayton.edu/faculty/jloomis/ece445/topics/egginc/pt_app.html
http://archives.e-insite.net/archives/ednmag/reg/1997/091297/19di_06.htm
http://www.aaroncake.net/circuits/lightdrk.htm