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Slot Car Computerized Lap Timing and Counting
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| I like lights on slot cars however the extra cost for the
"L" version or the high priced kits do not appeal to me. I put together
this article to help the others in the hobby that like me enjoy having
lights on their slot cars. The circuit I use can be found anywhere on the
net but I did modify it slightly for safety and efficiency. I will make
available a kit for anyone wishing to add lights to their cars. I some
pictures that I have collected or created and you can view them
here. As well here is where I got started
this page is a translation
from German to English with the authors permission of course. |
| I will start by saying this is not a hard
project but you may find it difficult especially if you have never tried to
read a schematic or picked up a soldering iron. I will try to make this as
straight forward as possible and if there is something that I could make
clearer please let me know because I do not want anyone to walk away from
this project frustrated. On the right you will find a parts list. I did not
include prices because frankly you might be able to get the parts cheaper
from your local shop. The parts list is for a complete Head/Brake/Running
light circuit. |
| Quantity |
Description |
| 2 |
5000mcd white LEDS |
| 4 |
750mcd or less red LEDS |
| 1 |
LM7806 Voltage regulator |
| 3 |
1N4148 Diodes |
| 3 |
150 --> 220 ohm resistors |
| 1 |
1.2K ohm resistor |
| 1 |
10K ohm resistor |
| 1 |
10 ohm resistor |
| 1 |
2.2uf electrolytic capacitor @ 16vdc |
| 1 |
.1F GoldCap capacitor @ 5.5vdc |
| 1 |
PNP transistor |
| 1 |
Wire, solder, heat shrink, PC Board. |
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The circuit is fairly simple and if you were
only wanting the head-lights then it gets even simpler but we will focus on
the complete circuit for now and go into the smaller ones later. The key to
the whole circuit is the GoldCap, this little component supplies power to
the circuit after you let go of the trigger. Therefore the brake-lights,
head-lights and running-lights will come on and stay on after the power
from the track has been cut. How long the LEDS stay lit will depend on how
many of them you have in the circuit for example, if you were only to
install head-lights then you might get 30 seconds of light from the LEDS
and the more LEDS you put in the circuit the shorter they will stay on.
I will go through the circuit step by step and please skip this if
you don't need this explanation. Power from the track enters D1 & D2, D1 &
D2 will isolate this circuit from the track and motor. The regulator U1 is
6vdc output which enters D3, D3 will prevent voltage from C1 from feeding
back into U1 when power is disconnected from U1 as well D3 drops the
voltage output of U1 to the rating of C1 which is 5.5 volts. U1 is always
charging C1 and providing voltage to the circuit for the LEDS until we let
go of the controllers trigger. When this happens C1 now starts to provide
voltage to the circuit and as well to the brake-lights. Q1 is in an off
state while voltage is applied to the track but once voltage is cut it
turns on letting the GoldCap power the brake-lights. |
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| This Schematic is for the complete setup,
head/brake/running lights. |
| This Schematic shows just the head-lights. |
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| This schematic shows the head-lights D6 & D7 as well
the running-lights D4 & D5. |
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| This schematic shows just the brake-light circuit. This
circuit must be used in conjunction with the main circuit to function
properly. |
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