Optical obstacle switch -
del50006
Description.
The 555 monostable has a 1 second period, If pin 2 gets low trigger
pulses of a frequency more than 1 Hz, the output pin 3 will remain
high, if the trigger pulses came in 10 second delays then output will
go on and off, so also the relay and the electrical load on relay
contacts. Like an integrator, it will not operate relay very fast. Even
in a fridge stabilizer they put something like this else the compressor
motor
is damaged on frequent black-brown outs.
Now for the LM567 part, The clock at pin 5 flashes the IR Transmitter
LED
LD1 at a frequency set by C7-R5. The IR Photo Sensitive
Diode or Transistor LD2 conducts when light is got from the IR LED. As
the
lights is in pulses, so also the impedance of LD2 goes low and high at
same frequency. This develops an AC waveform across R3 over a DC
representing Ambient light. If direct sunlight falls on this
arrangement, the Photo-diode
saturates, then this circuit or any other circuit won't work. But
when
ample protection from ambient light is made, some pulses good enough
for LM567 tone detection, 100mV rms, is obtained and it operates the
relay via a
LM555.
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Component Layout
Hand-Made
Artwork Positive
Film Solder Mask
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Right
Click Image, Save to Disk, Print to Scale.
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Build it Yourself.
The Artwork was made by a traditional PCB Artist with Artwork tape,
pads, Rotring Pen, and Knife.
This is scan of Hand-Made Artwork. Then
we go to a Offset printing, photo processing studio, he will make a
Positive and Negative of artwork with photography. This is what you
will need to make a PCB. Positive Film and Solder Mask.
The Artwork and Film are 1:1 or 1x, 300dpi scan. The Solder Mask is
shrunk to 1/2, it may not be usable, i have to still build some
graphics expertise and using the scanner. The component layout is an
assembly instruction. I have no idea how you will make PCBs out of
this, try postscript printing or ask a DTP professional. But if you
manage to get a scaled print, and you know screen printing or even have
a photo resist fluid. you can make prototypes at home. I used to do it
in my younger days.
Data sheets and Information.
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