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Knight Technology Q & A

  1. Scanner Questions
  2. 5- Step Sequencer Questions
  3. Plexiglas Questions
  4. General Electronics Questions
  5. Voice Box Questions
  6. Misc. Questions

Scanner Questions

Q:  I'm planning on converting my J.C. Whitney scanner into a good scanner,
like the one you have schematics for on your site.  But I have two
questions.  What kind of wire did you use to run from the battery to the
transistors (the fused one), and how did you split the wire off 8 times
to each transistor?

A:  I used a 8 gauge wire, you could probably use a smaller one like 12 gauge.
You will need to run this wire to a switched (ignition switch) 12 volt
source. e.g.. radio power.

I used solder to connect all the transistor's emitters in a row, from there
I ran a wire to the fuse then to a connector (for ease of installation in
the car) then on the other side of the connector I ran the 8 gauge power

Q:    I was reading the scanner electronics and got confused on where to put
the transistors and everything else that is needed could you help me out ?  Also how do I attach the
bigger bulbs to the scanner, do they solder to the board or what ?

A:  You will need to put everything on a circuit board (except the light bulbs.)  The light bulbs attach to a Scanner bar that you will have to make (see projects section) I made my circuit board from old PC cards that I removed all the components and sanded down the board until all the etching was off.  Then I drilled the holes for each component and soldered everything together.  You can see the boards I made here.

Q:  How do you actually make the "scanner" circuit? I was told to try a circuit that starts with a capacitor that charges. Then discharges to a transistor to light a lamp. The then transistor changes the circuit path to charge another capacitor and the process repeats itself. I am sorry that I cannot give more detail, but I am not that well versed in electronics. I do not want to use a 555 timer because I want the "sweeping" effect that is created when you use a capacitor.

A: Ok, you got things a little backwards and up side down....  I used a JC
Whitney "scanner box" and modified it for bigger bulbs. .  I needed
something that actually looked good so I built a "scanner bar" for the front
of my car, and a "booster box" for the JC Whitney scanner.  I trashed the
scanner bar that originally came with the JC box.  There are no schematics
for a scanner box on my site.  The only schematic is for the booster box.

When you say you don't want to use a 555 timer I'm guessing that you are
going to build your own scanner sequencer box.  I tried that and I couldn't
get it to work correctly after several hundreds of dollars, so I bought the
JC box for $30.00.

Either way, you need a sequencer to light the lights 1-2-3-4-5-6-7-8 then
8-7-6-5-4-3-2-1. The JC box had 8 outputs, each originally went to a little
light bulb in a flat scanner that ships with the box.  Instead of running
the small lights I used big transistors to amplify the output of the box to
run bigger automotive bulbs in my custom made scanner bar.

The 555 timer wont run the scanner it self, the 555 is required to make a
"pulse" that a counter or "sequencer" can run off of.  The counter runs 8
transistors in sequence 1-2-3-4-5-6-7-8 then 8-7-6-5-4-3-2-1, the
transistors are connected to 8 light bulbs in the scanner bar. The faster
the 555 runs, the faster the counter works, thus.. the lights in your
scanner move faster.  You can make a scanner circuit without a 555 (the JC
box doesn't use one) but I haven't tried it.

As far as the fading effect, you can add this feature after your scanner is
working correctly.  It is true that you use capacitors on the base side of
the transistors for it to get the fading effect with regular light bulbs. My
scanner fades just fine the way it is.  So I cant really say from
experience.  However the easiest way to get the fading effect would be to
use halogen light bulbs in the scanner bar.

My advice would be to buy a JC Whitney box and save yourself  allot of
money. Here's a link to it:

Q:  I am in the process of building my own scanner.  Where do you mount the resistors and stuff?  Do you build a box for them?

A:  I did stick the circuit board in a box from Radio Shack.  I made the circuit board it self from old PC cards that I removed all the components and sanded down the board until all the etching was off.  Then I drilled the holes for each component and soldered everything together.  You can see the board I made here.

Q:  Does the scanner only do the scanning from side to side or is it programmable to
scan in one direction. Like to indicate a turning signal. Also does it have the
"sweeping" effect. Where the light lights up and then fades off. The
transistor/ capacitor technique.

A:  The J.C. Scanner only has one mode of operation it has 8 lights and only
scans back and forth.  As for the "fading effect"  it does not have this
capability as it comes shipped from J.C. Whitney but it can be done by
converting it to bigger bulbs.  Halogens are the best for fading however, my
scanner uses regular "interior/backup" light bulbs and if you got the thing
scanning back and forth at a good speed it does the fading also.

Q:  I built the scanner box and electronics
but I am having a problem. I got everything wired up and connected it to
power,and the control box worked but the scanner bar didn't. I followed your schematic
exactly so I am kind of stumped. I don't know a whole lot about
electronics but I think I did everything correctly...should I heat sink
the transistors? I just used regular car bulbs...the only thing I did
differently from what you did was that I put in a 10 amp in-line fuse instead of a 5
amp fast acting fuse...

A:  Heat sinking the transistors
will have no effect if the circuit is not working. The fuse should not have
an impact on the circuit unless it is blown (you can fry the transistors
with a 10 amp fuse by the way).   Did you use the
correct transistors?  They need to be PNP not NPN.  You must have the 270
ohm resistors on the base side of the transistor or you will fry the
transistors.  Umm... How bout the diodes, they only flow current in one
direction, if they are in the circuit backwards it will not function.  Try
turning one around to see if you can get one light to work, if it does light
up, turn around the rest of the diodes and the circuit will work with all
the lights.  This is a pretty simple circuit, we can figure it out.

Q:  Where do I order the J.C.  scanner from?

A:  The J.C. scanner is available at:

This is THE original place to get these scanners, you can find them on e-bay
for outrageous prices.  You can send off for a printed copy of their
catalog, they have tons of stuff for cars.  If you order a scanner from them
you expect to wait about a month or two to receive it, they always have to
back order them, probably because people are buying them in bulk and selling
them on e-bay.

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5- Step Sequencer Questions

Q:  (5-step Sequencer) I got it all together but when I hook up power it starts blinking in sequence
like Christmas lights constantly. And if I turn down the pot in just lights
them all up at once but they stay on. Any suggestions?

A:  Sounds like you got everything right up until the SCR area....  The
SCR's are the pieces that "catch and hold" the circuit on.  They receive a
signal from the 4017 counter which triggers them on and they should stay on.
If all the LED light bars are flashing like a Christmas tree then at least
the timer and counter are working.  The lights should flash in the
appropriate sequence 1-2-3-4-5 right now,  right?  and they are just not
staying on.
Make sure you have the correct 470 ohm resistors before the output of the
SCR's into the transistors.  If the resistors are missing or incorrect the
SCR will not function correctly.  The transistors are apparently functioning
correctly at this point.  Also make sure the SCR's are hooked up correctly,
if the anode and cathode are reversed it wont work either.  When you turn
the pot, the reason they all come on at once is that the timer is going so
fast that it looks like they are on constantly, but they are infact
switching on and off so fast us humans can't see that.  (Kinda like a TV
screen, it's a bunch of still frames displayed very fast, but to the human
eye it looks like moving pictures...) 

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Plexiglas Questions

Q:  When cutting Plexiglas glass what kind of blade do I use?   A blade with  little
teeth or a blade with bigger teeth ?

A: You want to use a fine tooth blade (lots of teeth) and a slow speed when
cutting Plexiglas.  If you cut it to fast it will melt.  If you use a coarse
(few teeth) blade it will shatter.  You can also cut Plexiglas with a
special tool (or a utility knife with a new blade) available at any hardware
store for a few bucks. It scores the surface of the plastic.  After you
score it 3-5 times you need to set the score mark along the side of a table
the snap the Plexiglas in half.  It will snap along the score line perfectly
straight. it may take some time to get the process correct so try it on a
scrap piece first.

Q:  Is there a certain way to paint the Plexiglas with the paint.    I mean
like do I have to sand it down then paint it ?  Or do I just paint it and
add more coats of paint to it as I go along ?

A:  Are you talking about the scanner bar or the tail light blackouts?  I'm
assuming that your talking about the scanner bar....  You will want to clean
the Plexiglas with rubbing alcohol first.  Then all you do is coat the
plastic with the stained glass paint, one coat at a time with about 5-10
minutes drying time in-between coats.  Keep coating until you think it's
enough, the more coats you put on, the less light that can get through.

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General Electronics Questions

Q:   I was looking over the schematics on your website under the voice and
step-down circuits and I noticed you used 12 volt 1 amp voltage regulators.
I was wondering if that is correct?  I was planning on using 5 volt
regulators because I didn't think the circuit components could sink that much
voltage.  Is there a reason for not breaking the voltage down from 12 to 5 volts?

A:  I tried the 5 volt way, I couldn't get the LED's to be bright enough.  The
3915 chip is rated at 3-25 volts, so there wasn't any worry about smoking
any parts.  Infact the circuit will work directly off a  car battery without
the regulators.  Without them though the brightness of the LED's would vary
with the car's electrical system which can be between 10-16 volts.  I used
them to keep a steady level of brightness.  You can run a single LED of a
car battery if you use a 1k ohm resistor, it isn't the voltage that really
matters its the amount of current flowing through the LED.  If you flow to much
current through a LED you will pop it, the resistor merely slows down the flow.

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Voice Box Questions

Q:  I am not to good with electronics.  I was wondering if you could build
me a voice box of KITT, and I will pay you for doing it for me.  Also is
there a way to explain the modification of the J.C. Whitney light a little better
because I am not to good with electronics I always blow something up.

A:  When I started to design the circuits I didn't know much about
electronics either.  Go get the book "Getting started in electronics" from
Radio Shack.  This book will tell you tons about how the individual
components work.  There is a picture of this book in the projects section,
under help.  Right now I am not able to build these parts due to time
constraints, maybe sometimes in the future I will be able to.

Oh and as far as "always blow something up"  I did to....  about 2-4 hundred
dollars of parts, by time I was done with all the schematics.  At least you
have something to go by, I did not.  You can do it if you take the time too

Q:  Hi, I just finished building the circuit for my scanner, works great thanks. 
My question is, what kind of transistors do you use for the voice boxes?  Are
they the same ones as with the scanner? 

A:  The answer is no, but you could use them if you had to.  I used smaller ones (little round ones with 1 flat side)  you can get them at Radio Shack in a package of 10 (around 3-4 dollars) allot cheaper than the bigger transistors.  Be shure to get the correct type as in either PNP or NPN, wichever the schematic calls for.

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Misc. Questions

Q:  Did you say that you were going to just use the normal summit digital gauges or did you say you were going to reconfigure it to resemble KITT's?

A:  As far as the gauges, I used VDO cockpit series analog gauges witch are pretty
neat.  The speedometer has a regular "pointer" on a face that has
numbers like a regular gauge. It also has a digital reading for the mileage
and also doubles as a trip odometer.  All the other gauges don't have the
digital reading.  I couldn't afford the digital gauges from Mark or Eric at
the moment so these gauges are the place holders for now.  When I got my
latest Summit catalog I saw an add for a custom digital gauge package.
  This would be an excellent start for anyone making a digital Knight dash. 
If one would know how to solder and drill a circuit board re-arranging these
LED's to resemble KITT's dash would probably be pretty easy.

Q:  I was wondering  if you would sell me one of your voice boxes at an reasonable price?

Q:  Is there any ways you might sell me a high powered scanning light you have

A:  I cannot sell you a voice box / scanner because I only made 1 for my car.
Perhaps someday I will sell the parts for conversions but right now I'm just
to busy with work and my other projects.

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