This invention concerns a remote control system,
particularly a type suited to perform remote control operations
like opening/closing a door, connecting/disconnecting a burglar
alarm system, etc.
More particularly this invention concerns a remote control
system incorporating a multi-channels transmitter and a receiver
capable of driving an actuator to accomplish a desired operation
when receiving from the transmitter a predetermined numerical
code equal to a code stored in the receiver.
The invention has a preferred and particular application,
in remote control systems using infrared, radiofrequency,
ultrasounds, etc., and it will be disclosed in the following
with reference to such an application, which however is not to
be understood as limiting the scope of the invention.
Remote control systems are devices of widespread use and
generally include one or more remote control transmitters,
provided with a memory in which at least a code is stored, and
one or more remote control receivers, fitted to the actuating
device or to vehicle to be controlled, and adapted to extract
from the transmitted signal an unique code that enables the
execution of a desired operation. By using a code made up by a
relatively long binary combination, the remote control
transmitter becomes a sort of quite safe "key" for the user.
Remote control transmitters and receivers are
manufactured as mass production devices and subsequentely
customized with proper identification codes.
In the known systems, the code is selected in advance and
stored in the devices by the equipment manufacturer. As an
alternative the final user can select his/her own identification
code and have it stored by means of a suitable programming
device.
In systems where the choice of the identification code
is left to the user, the code can be stored either manually or
by using a programmer. Where the storing is manually
accomplished, usually through a plurality of microswitches or
"dip" switches located inside in transmitter and possibly also
in receiver, serious safety problems araise, for example in case
the device is (even temporarily) lost, because such code can be
discovered through a mere inspection of the switches.
In systems that use a programming unit or programmer,
the user is compelled to purchase also this unit, or to have the
code stored by the installer, which implies a number of
drawbacks even in respect of the safety.
In remote control systems where the manufacturer takes
care of selecting and storing the codes, the storage is carried
out so as to render quite difficult an unauthorized duplication
of the code, and a better degree of safety is obtained. However
this procedure involves both a loss of flexibility and
considerable difficulties and complications.
Other inconveniences of those known systems known as
"Rolling code" originate from the fact that, in order to provide
the final user with a new transmitter, the installer has to go
to the controlled premises and store the code in the receiver.
On the other hand, in systems known as "Random", the installer
must keep a card with a non volatile memory for each
installation, in order to be able to reprogram a transmitter
without physically going to the controlled plant or premise.
The object of this invention is to overcome the above
described limits and drawbacks of the prior art devices, and in
particular to provide a system in which the final user is able
to select and store a code of his/her own both in the
transmitter(s) and the recever(s) of a remote control system,
with the utmost safety and without need of using complex
equipments, nor to accomplish manual operations on the receiver
and the transmitter.
These objects are achieved through a remote control
system according to claim 1. Further advantageous
characteristics are recited in the dependent claims.
The remote control system according to this invention
provides for using code portions or partial codes of different
level in order to improve the system safety, More particularly,
according to an embodiment of the invention, there are defined a
distributor code, an installation code, a plant code and a
personal code that together make up the complete identification
code (CODE) of a given device, plant or car, with each partial
code being entered and stored separately in both the receiver
and the transmitter as steps of a programming procedure.
The invention will now be disclosed with reference to the
attached drawings of preferred but non limiting embodiments
thereof, in which:
Fig. 1 illustrates a remote control system according to
the invention; Fig. 2 is a block diagram of a remote control
transmitter according to the invention; Fig. 3 illustrates a programming step of the transmitter
according to the invention; and Fig. 4 shows a hierarchical structure of partial codes.
With reference to Fig. 1, a remote control system
according to the invention comprises - in its simplest
arrangement - a remote control transmitter, indicated by
reference 10, and a remote control receiver 20, connected to an
actuator 4 (shown in dotted lines) or other circuit or device
adapted to carry out the required operations, e.g. the
opening/closing of a door. The remote control transmitter 10 is
preferably provided with 2/4/8 or more channels, with each
channel being associated to a different code.
Usually there are provided two or more remote transmitters,
for example one being given to a second user, and two or more
receivers, for example to control more than one gate or door
through the same device. Besides, the transmitters and receivers
can be of various types, for example infrared devices,
radiofrequency devices (radio control), ultrasounds devices,
with the programming being carried out (preferably) through
infrared signals, without this being construed as a limitation.
Preferably, the receiver is of the so called "autolearning"
type, i.e. capable - when properly enabled to do so - of
receiving and permanentely storing the code from the
transmitter, i.e. to be programmed. However also this feature is
not to be construed as a limitation.
The transmitter 10 is housed in a plastic material
container 14 and usually equipped with a plurality of
independent channels, each of which is univocally associated
with a receiver 20 by an enabling digital code. A transmitter is
generally provided with one code for each channel, while the
receiver is usually responsive to one code only.
The system according to the invention further provides for
at least two separate encoders (30, 40, 50, 60 in Fig. 1) in
order to enter a desired digital code in the receiver and the
transmitter, that is "to program" or set these devices.
The encoders can be either portable devices with a
construction like that of the transmitter. or bench type
apparatuses capable of setting a large number of transmitter and
receivers, and in this case they are provided with a holder in
which the device to be set is located, and the code transmission
is continuous in order to speed up the encoding of a large
number of devices.
According to the invention, said two or more encoding
devices 30, 40, 50, 60, are employed in succession to store in
the transmitter(s) 10 and the receiver(s) an identification code
CODE or a portion thereof.
More particularly, according to the illustrated
embodiment, a complete identification code CODE comprises a bit
string, and each encoder supplies a portion (partial code) of
this string.
With reference to Fig. 3, in a preferred embodiment of
the invention, a portable encoder is housed in a container 34
substantially equal to the container 14 housing the transmitter
10, and provided with two pushbuttons T1 and T2 and with two
emitters, for example two LEDs, respectively 31 and 32.
The encoder can further comprise a plurality of
microswitches or dip switches 33 through which a partial code is
set up. As an alternative, the partial code can be stored in a
non volatile memory.
In an alternative embodiment (not shown), preferably for use
at (dealer) distributor level, the setting means of the encoders
can include a keyboard, or an interface for a PC connection.
According to a preferred embodiment to be disclosed
later, there are provided four (levels of) encoders, of the
infrared type, each being enabled for entering the code in the
transmitter in a hierarchical manner.
As shown in Fig. 3, the transmitter 10 is provided with
a receiving portion RI comprising an infrared photo-transistor
12 for receiving the code or portions thereof, and with a radio
transmitting portion TX for sending the code to the receiver 20.
Referring now with more details to Figures 2 and 3, the
transmitter 10 is contained in a housing 14, preferably of a
plastic shockproof material. Device 10 comprises a transmitting
portion TX capable of sending command codes to receiver 20, and
a receiving portion RI capable to receive codes from the
encoder.
The housing 14, in correspondence of the transmitting
section TX, provides an infrared emitter 11, particularly a LED,
and two pairs of pushbuttons, CH1, CH3 and CH2, CH4, for
transmitting an activation code over one of four channels. A
switch 13, provided with two positions A and B, allows to double
the number of available channels, since when the switch 13 is in
position A, channels from 1 to 4 are operable, and in position
B, the CH keys enable channels from 5 to 8.
On the outer surface of housing 14 the receiving section
RI of the transmitter 10 there is located an infrared receiver
12, for example a photodiode, a PIN or similar device, which is
used either in the codes entering procedure or in the
autolearning procedure.
As better shown in the diagram of Fig. 2, besides
receiver RI and RF transmitting portion RX, the transmitter 10
further comprises a memory M, of non volatile and re-writable
type, that stores the digital enabling codes for the several
channels, and a microcontroller or a microprocessor indicated
with µC. Preferably memory M is an EEPROM (Electrically Erasable
Programmable Read Only Memory).
The code portions Cp, Cd, Ci and Cu of a given channel
are supplied in different locations and at different times by
the different encoders 30, 40, 50, 60 and are stored in memory
M. As schematically shown in the enlarged detail of Fig. 2, the
portions Cp1, Cd1, Ci1 and Cu1 of a same code are stored at
different memory locations and not adjacent to each other, but
however the microprocessor is capable to retrieve the code
portions and join them together to obtain the complete code.
When the user pushes one of the control pushbuttons CH, the
microcontroller µC reads from memory M the partial codes that
make up the complete code of a given channel and pack them again
to build the string of the complete code that is then
transmitted by portion TX. A similar storing arrangement can be
provided in the receiver(s) 20.
The length of the partial codes Cp, Cd, Ci and Cu is in some
way dependent from the number of different encoders that are
assigned to a given code/channel. For example, the number of
bits forming the Cd partial code assigned to the distributor
must allow to identify each distributor with his own code. By
using 5 bits for the partial code Cd, 32 (25) different codes
are available and as a result an equal number of encoders can be
assigned to as many distributors. The number of bits identifying
a distributor can also be increased, however it is preferable to
assign a larger number of bits (i.e. of identifiable
combinations) to the installers. In other words it is preferred
to lengthen the partial code Ci in order to ensure the maximum
customization of a transmitter.
As shown in the hierarchical diagram or tree in Fig. 4,
a transmitter is manufactured including a partial code Cp
(manufacturer) of 5-10 bits that identifies the reseller. This
way resellers that are geographically near to each other cannot
have transmitters that could be compatible.
Then the distributor or reseller, by means of an encoder
supplied by the manufacturer, can select and store at suitable
locations of memory M a partial code Cd of his own (or second
level code), made up for example by 10 or more bits, that
identifies the installers who depends on a same distributor.
Also in this case, to installers which are near to each other
there are assigned devices that are not compatible to avoid
interference. The distributor will also supply the installer an
encoder of 20 or more bits that will allow this latter to
customize the transmitters sold by him to the final users.
Finally, the installer can supply to the final user an
encoder with 20 or more bits so that the user can store a
personal code Cu of his/her choice. Moreover the final user can
change the final portion Cu of the code every time this is
deemed necessary or desirable.
The allocation of the partial codes in Fig. 2 is shown
as sequential, in case interleaved with that of other channels,
however many different arrangements of the memory allocation are
possible, either in accordance with particular algorithms or
with different bits interleaved. It is however to be noted the
hierarchical arrangement of the partial codes according to the
invention. More particularly, the microcontroller will prevent
writing of a partial code unless all the hierarchically higher
partial codes have already been stored.
The remote control receivers or receiving units 20 are
provided with a memory and with a microcontroller (or
microprocessor) similar to those used in the transmitter and for
this reason have not been disclosed in details. The receivers
can store either the entire code (i.e. distributor code +
installer code + final user code + personal code), or only two
or more partial codes, such as for example the distributor code
+ the final user code, and so on. The encoder for the receivers
is in principle equal to the portable encoder described with
reference to Fig. 3, but without the (dip) witches 33 since the
relevant code is supplied by the manufacturer with a serial
number and cannot be changed.
Once the complete code has been stored in the
transmitter, the receiving unit is ready for operation.
In addtion to conferring a high degree of safety to the
plant or other article to be controlled, the sequence of partial
codes learnt by the receiving unit is usefull as a safeguard for
the distributor's and installer's sales. For example, in case
the installer code and the final user code are correct, but the
distributor code does not match, then the transmitter will not
be capable of commanding the desired operation, since it comes
from a different distributor from the one who sold the previous
transmitters. Thus the sales of the distributor are safeguarded.
In the system of the invention, the installer will
further be able to further customize and make safer the plant
with the encoding of the receiving units.
An encoder with a code preset by the manufacturer and
different for each installer, allows to enable autolearning of
the transmitted code by the receiver unit. The enabling of the
receiver unit to learn the transmitter code takes place after
the encoder code has been set by means of infrared transmission.
For example, after the installer has customized the
receiving unit using his own encoder, the code of the
transmitter(s) learnt by the receiver unit cannot be changed,
unless the encoder code of the installer who supplied the
transmitters is introduced again in the device.
This way, an installer who is servicing a plant he has
not installed, will not be able to release the receiver unit
with his encoder and to store a new code. In order to customize
all the plants of an installer, only an encoder for receiving
units will be sufficient. In case an encoder is lost or stolen,
it will be possible to get from the installer an encoder enabled
to release only, and only by fulfilling predetermined conditions
(for example supplying the serial number of the lost encoder),
and the new encoder can have either the same original code or a
different one, as desired by the installer.
The simplicity of use, together with the safeguard of
the sales at various levels (distributor, installer, etc.) makes
the system of the invention extremely advantageous, also owing
to its easy programming.
Although the invention has been disclosed with reference
to preferred embodiments, it is generally susceptible of other
applications and changes which fall within the scope of the
invention, as it will become evident to the skilled in the art.