|
PERFECT FLASH
System Description
The PERFECT FLASH system is designed to sequence turn signals and
NOT BRAKE LIGHTS. All kits and modules conform. The PERFECT FLASH system is designed fail safe not to sequence brake or emergency lights.
It is against DOT regulations to sequence brake lights. This applies to
automobile manufactures and has been adopted into the motor vehicle laws of many states.
The PERFECT FLASH system consists of 2 modules that each control a
set of tail lights and communicate with each other over a phone cable to determine if turn or brake light operation is needed for each engagement.
See Specifications for technical information
The latest 2010 electronic components as used in modern automotive
electrical systems are used in the PERFECT FLASH system. Each module is computer controlled, buffered to the environment, and designed for fail-safe operation.
Comparison to other systems on the market
The PERFECT FLASH module (bottom) is fully protected for the
automotive environment. The OTHER typical module (top) is ready to fail at any moment. It is clearly lacking the protective circuitry necessary for it to operate any length of time in an automotive
environment.
NO MORE DYNAMITE!
When we go to car meets, sooner or later someone starts complaining
about his failed Dynamite Stick sequencers and it’s going to cost another Hundred Bucks to get new ones. See the dissertation on failed transistors. Dynamite Sticks got their name from their physical shape
and the short life to burn out. They have transistors (or FETs or whatever) potted inside in secrecy just waiting to burn out. You can’t fix them, just get your next hundred bucks out. MBTF = 2 years
nominal. We find it funny that some manufacturers brag about using Dynamite Sticks in their systems. The joke is on who buys them.
Why Power Transistors and FETs are not good choices for switching light bulbs
When a light bulb is switched on, the filament is cold and a very low
resistance. As current flows, the filament warms (very rapidly) and glows with a specific resistance value that determines the current flow
for an applied voltage. The typical brake or turn signal lamp (1157 or 3157 or 4157) draws over 2 amps (give or take} when it is glowing. When the filament is cold it takes about 10 times that amount of
current to start the heating process, or over 20 amps. Flashers of yesteryear are of a bi-metallic contact type that open and close a heavy-duty contact (like a relay contact) to control the current flow to turn
signal or hazard warning bulbs. The design criteria from the D.O.T. are they must cycle for 200 hours or about 20 years of intended life.
Today’s modern flashers use electronic circuits and they are still switching with relay contacts because they must meet the 200 hour cycle life specification. If Transistors were employed, the life is less
predictable and variations in load would have a greater effect on lifetime. Below is a picture of a typical power transistor that might be
used in a flash arrangement. The color picture next to it is a thermal image showing high heat at the bond wire interfaces inside the package when current is flowing.
This picture is the magnified chip inside a power transistor package showing the wire bonded connections for the collector and emitter where the high current flows as it switches on and off.
The pictures show a new device, one that is starting to fail from current
spiking and one that has totally burned out from over load. The constant current hammer effect starts to weaken the connection point and resistance builds causing excessive heating and melting of the
silicon chip. Eventually the resistance increases to the point where it causes the current to melt the chip and fail. This is why regular semiconductors are a poor choice for switching light bulbs on and off
and why Dynamite Stick flashers or other cheap transistorized flashers fail in a couple of years if they are used regularly. If transistors were
good for this application we would have used them. They are CHEAPER. Instead, PERFECT FLASH incorporates special automotive lamp driver components that are designed to work beyond the life of the
automobile. The switching devices are used in automotive computers and are designed to switch automotive lamps. They are called highside drivers.
|