A while back someone asked for an answer to a problem. 

They set in line with their truck and want to catch a few winks.  They also would like to be alerted when the truck in front of them moves. 

Someone gave me this schmatic. 

I understand the principle of the drawing, but do not know the sizes of the needed capacitors, resistors,comparator,MOSFET,or LED.

#1 is a capacitor

#2 is a capacitor

#3 is a resistor

#4 is a resistor

#5 is a capacitor

#6 is a line that did go to a potentiometer.  The potentiometer would have controlled the distance the sensor would have worked at.  The max range of the sensor is 21 ft.  I just took the potentiometer out because when the truck in front gets 21 ft away the buzzer will go off and that is just fine.  I did not need the buzzer to go off at a different distance than 21 ft. 

#6 Do I need a resistor or anything in line 6 or can the negative from the comparator just go to ground the way it is drawn?

#7  I know nothing about comparators.  Any idea what size or mfg. for this item?

#8 is a resistor again

#9 is a MOSFET.  I do not know from the schmatic if I need a P-channel enhanced or a N-channel depletion.  Again what size or mfg. and what kind  ??

About all I can do from this schmatic is buy the fuse,power switch,voltage regulator,LED, buzzer, wire and wire it all up.  

Anybody want to tackle this?  or  Tell me where/who to talk to for the answers.  Just name your royalty. 

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