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Smart Brake Light for Automobile.
Sheets of Drawings
TITLE: Smart Brake Light for Automobile
BACKGROUND OF THE INVENTION
RELATED APPLICATIONS:
This application claims priority and is entitled to the filing date of U.S. Provisional application Ser. No. ######### filed MM. DD, 2004, and
entitled “Smart Brake light for automobile.” The contents of the aforementioned application are incorporated by reference herein.
INCORPORATION BY REFERENCE: Applicant(s) hereby incorporate herein by reference, any and all U. S. patents, U.S. patent applications,
and other documents and printed matter cited or referred to in this application.
FIELD OF THE INVENTION:
The present invention relates to means, in automobile safety.
DESCRIPTION OF RELATED ART:
TBD
SUMMARY OF THE INVENTION
The present invention teaches certain benefits in construction and use which give rise to the objectives described below.
Brake light serves as indicator that brakes of automobile is applied, it give out warning that this vehicle is slowing down so other vehicles
behind it can be prepare for it. However, today’s brake light isn’t very effective in terms of giving out warning signal since it only provide one
sole information that brake pedal has been pressed. It can’t differentiate a gentle slow down and hard braking stop. This invention intend to
improve on it by providing more information when vehicle braking.
And it his being done via a low cost, reliable way. And it is easy to adopt with today automobile build without other changes. No need for
added wiring nor switch other than the brake light module itself.
Two stages (or more) of brake light are provided. The first stage, like our current brake light, turned on by a switch at brake pedal. The brake
on come up at one and only one condition… driver hits brake pedal. This method had been proven very reliable for long time. We have no
intension to change it. This invention is to provide an additional amount of light as indicator that vehicle has slow down more rapidly. More
intensive brake light comes up if two conditions are both met. A> the first stage of brake light is up. B> A beyond threshold g-force has been
detected due to de-acceleration of vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
DETAILED DESCRIPTION OF THE INVENTION
CLAIMS
ABSTRACT OF THE DISCLOSURE
ABSTRACT
Brake light serves as indicator that brakes of automobile is applied. So vehicles behind that automobile know it’s slowing down and shall
keep a safe distance from it. However, the rate of slowing down via braking may vary within a wild range. Often see driver with his/her brake
light on but vehicle doesn’t seem to slow down much. The other scenario, vehicle under emergency may apply great deal of braking force
and slow down rapidly. However, with today’s brake light system, it doesn’t give out any more indication than the first case driver who is just
merely adjust his/her speed slightly.
This invention intends to change that. Vehicle slows down more rapidly should give out more clear, stronger message to vehicles behind it.
When apply brake to vehicle, a switch turns on and apply electric power to brake light module. Basic brake light lights up under all condition
(see fig 2,3,4). A g-force sensor is used to detect rapid slow down of speed. When g-force detected beyond a thresh hold(0.3 g in our
example), additional light is giving out to indicate rapid slow down. (see fig 3)
Background of the Invention
1. Field of the Invention
The present invention is a effective way to improve automobile safety.
2, Description of the Prior Art
Random Access Memory, include SRAM or DRAM, is a very popular hardware device among embedded or computer system. Often, more
than one piece of RAM is used in one system. Function of memory is to retain value of write operation for future read access. Unless non-
volatile, memory location, without prior-write operation after system reset, its value should be undefined.
An authentication mechanism is used as a device to provide authentication keys for CPU to perform authentication check. Device is used to
protect illegal copy (or pirate copy). Authentication-check often takes place when system first boot up, it verifies if this device is properly
authenticated, otherwise fails this process. Even the entire hardware including software program reside in system ROM being duplicated,
without correctly complete authentication process, system won't function but go to a halt state. Such device connects to system's CPU via
various kind of access interface. Authentication device often to be an individual part, therefore, occupies PCB space and stands a cost.
Summary of the Invention
This invention provides a method to integrate an authentication mechanism with Random Access Memory. One goal we try to achieve via this
invention is to share existing RAM interface to CPU without adding extra pin. This invention only utilizes these supposedly undefined read
operations to perform authentication process to lower system cost and easy design.
A conventional RAM keeps values written to its locations unchanged for future read operations. A read operation on a location where hasn't
been written before gets undefined result on conventional RAM. Therefore it's a common rule for computer program not to trust such a read
operation. However, in case of anti-pirate RAM, CPU can obtain authentication keys through these read operations. Memory location once
written, from that point on, will only perform function of conventional memory. That’s to hold value written unchanged.
Memory devices usually have large number of memory cells. They are arranged in word by addresses. Consider that CPU will also need
some memory to execute authentication check program, we may need some portion of RAM for memory function while one part of them to
provide authentication keys. In order to perform both function at a same time, we divided entire memory device into sections. After system
reset, all sections are in default mode to provide authentication keys. Any section needed by CPU can be converted into memory function by
simply issue a write operation to it, which is pretty reasonable to start a memory function any way. The write operation brings one section
back to memory function while leaves other sections unaffected to serve authentication function. Once the authentication is done, All sections
can be used as memory function… or not. For instance, an 8kx8 memory piece has 8096 memory words, each word has 8 bits. We can
divide it into 32 sections; each section has 256 bytes. (This is an example, doesn’t have to be exactly this partition) When boots up, system
can use up to 31 sections as memory but only need one section for authentication keys. (And that should be plenty)
As we go alone with example above, each authentication section has 256 bytes space for authentication function. These locations are used
to provide device ID, read-incremental authentication input key and authentication return keys. As Fig.~sectionmap~ shows. The first 8 bytes
of each section are used to provide device ID. Contain of this ID is a fixed value as long as a section is serving authentication function. It’s
defined by vender and by product. Authentication program can read this field to ensure this section is still serving the correct function. If its
value doesn’t match the ID, which says either this section is the wrong device or this section already out of authentication function and turn
into memory.
The second field is a read incremental authentication input key. Contain of this field increments every time it gets read. CPU can set this field’
s value by reading it the correct number of times. Its value will be used to calculate rest of authentication keys. If someone tries to defeat this
authentication system by placing a copy of known keys, this field is designed to obsolete them. Since this field’s value increases every time it
gets read, we can designed our authentication program to read this field a random number of times before accessing rest of authentication
keys. Using read incremental counter to set a value may need many access cycles, yet it certainly avoid any write operation which will bring a
section out of authentication mode and into RAM mode. It’s advised to limit the number of bits. In the case of our example, 10 bits, any
desired value could be reached within 1024 accesses to the counter. Since this field plays a part to generate authentication keys, pirate
copier can’t predict which value out of 1024 CPU is going to set for this field (if a true random number was used), there is no way they can
predict a image of authentication keys to pass the check.
As fig~sectionmap~ shows, rest of the section is used to provide authentication return keys. These authentication keys are a function of few
combinational inputs. These inputs are product specific secret authentication key, authentication input key and access address. Access
address is the address within RAM. Each location has unique one. Authentication input key is decided by read incremental counter as
described above. Value last time this field got read is used as authentication input key.
Secret authentication key is the one distinguishes one authentication check from the others, even base on same part. There can be more
than one product using this same authentication device, as long as they are pre-programmed with different secret keys, the return
authentication keys won’t be the same. Hence a device used by one product can’t be interchangeable with the ones within different type of
product. Due to its secret nature, no one knows other system’s secret keys; therefore there is no way to avoid choosing same secret key. If
that happen, it’s a collection between two secret keys. To minimize the opportunity of key collection, it’s advised to pick a long length for the
secret code design (for instance 32 bits, 64 bits or 128bits). And we should avoid picking too simple a combination for secret key such as all
0 or all f. This secret key should be pre-program into device prior being used in a system. Once it is programmed, there shall be no way to
retrieve it back, even by the designer. The only method to verify secret key has been correctly programmed is to perform an authentication
check. The method to program secret key is not described in this article.
The functions to generate authentication return keys are also not described in this article. However function for these applications should
provide certain level of protection for secret key and generates enough variety for return authentication keys. Secret key must be hard to trace
back thru reverse engineering. While return keys must full of varieties that two devices with different secret keys shouldn’t have identical
return key set, so they can’t be interchangeable. Individual function like bit scramble, exclusive-OR and modulation are usually good sub-
function candidates for a combination of functi
