GB2413649A

GB2413649A - Wireless transceiver remote control system

Info

Publication number: GB2413649A
Application number: GB0409539A
Authority: GB
Inventors: Kevin John Kirk
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-04-29
Filing date: 2004-04-29
Publication date: 2005-11-02
Also published as: GB0409539D0

Abstract

A wireless transceiver data communications system provides an encoded data communications system to operate within the low power, license free radio spectrum to provide remote control and monitoring functions. It consists of a pair of modules that are substantially the same and linked wirelessly together. Each module contains an antenna 1 matched to a transmitter 2 and receiver 3 which can be switched from transmit to receive under the control of the microprocessor 4. When the user applies an input signal to the module interface, it is encoded by the microprocessor into a serial datastream and passed to an encoding system 11 which encodes the stream into a suitable form (such as Manchester encoding) and then adds an identifier code and creates a packet of data. Before the packet is transmitted, the microprocessor uses the receiver to detect whether there is another operating on the same frequency in the vicinity that could cause a collision.

Description

Enhanced wireless remote control system Descrintion The system comprises

of two or more modules linked together wirelessly using frequencies that have been designated by governments for license free data communication and control functions. Each of the modules is substantially the same as the other and are created at a minimum as matched pairs sharing a unique identifier. Each module consists of the following (see figure 1): (a) An antenna matched to the frequency of operation.

(b) A crystal, resonator or SAW locked radio transmitter and receiver (c) A data communications protocol unit (d) A microprocessor that controls the operation of the transmitter and receiver and decodes and verifies the unique identifier (e) An interface system linking the module to the users system Figure I shows a representation of a complete module. The modules are built onto a circuit printed circuit board onto which all the components are mounted (1) . The internal circuitry is connected to a single connector (2) through which the power and control signals are applied or extracted from the system. The integrated system antenna (3) can either be etched onto the printed circuit board together with the electronic components (4) or, for longer range a helical stub antenna that is conformance coated along with the rest of the module to create a monolithic whole.

Electronically (see figure 2) each module of the system will have an antenna (1) which is either etched on the circuit board or in the form of a single ended stub antenna. This is matched to a transmitter (2) and receiver (3) which can be switched from transmit to receive under the control of the microprocessor (4) depending on the function the module is undertaking.

The Receiver is connected to a data communications module that provides a suitable decoding mechanism (5) (such as Manchester Encoding) to ensure data integrity. The receiver will also feature a carrier detect circuit (6) which is applied as an input to the microprocessor to allow the system to monitor the transmission frequency to ensure that if other modules or systems using the same frequency then the module will wait until the waveband is clear of traffic before starting to transmit to avoid collisions.

The output from the receiver is applied to a demodulator (7) which in turn is connected to a decoding mechanism (8) which will check the incoming data-stream against a pre programmed identifier to ensure that the incoming signals are intended for this system. The decoding mechanism will also perform an integrity check, an example being a CRC check, to ensure the data has been received error free. The data payload is then extracted from the datastream and presented to the microprocessor (4) using a serial or parallel dataport (9). The microprocessor will then extract the control information and present the output through the interface (10) to the user's system. The interface will feature suitable level and current amplification to allow simple interfacing to the user's system. An example of one port of the user interface is shown on figure 3. The microprocessor will ensure the correct operation of the receiver and will control the complete reception process using a stored program and the dataport (9) to the receiver module. \' The Transmitter is integrated into the system together with the receiver. When the user applies a input signal to the module interface (such as a switch closure - see figure 3 for an example of a input interface ( 12) which is part of the module interface - (10) on Figure 2) it is encoded by the microprocessor into a serial datastream and passed to an encoding system (1 1) which encodes the stream into a suitable format for data transmission (such as Manchester encoding) and then adds the identifier code and creates a packet of data together with a data integrity portion (an example being a CRC checksum). This is then presented to the transmitter circuit, which is also under the control of the microprocessor. Before the packet is transmitted the microprocessor will use the receiver to detect whether there is another carrier operating on the same frequency in the vicinity that could cause a collision. If there is another carrier then it will wait until the other transmitter stops transmitting before transmission can proceed.

A further integrity check is built into each module to ensure the receiver has correctly received and decoded the data. Once the receiver has received, decoded and extracted the data payload it is presented to the microprocessor. The microprocessor will then send an acknowledgement back through its transmission system, using the method described above, to signal to the originating module that it has received and decoded the data correctly. If the originating module does not receive this acknowledgement it will resend the original data packet at pre-programmed intervals, based on the operating restrictions of the frequency of operation which limits the maximum transmission times in any one hour, until the packet has been received and acknowledged.

The modules will be capable of operation with purely digital inputs and outputs (such as driving relays - (13) on Figure 3 - and accepting switch closures) but can also operate with analogue inputs and outputs for process control purposes. An example is shown in figure 3 (14) - which is part of the module interface (10) on figure 2. In this example the analogue (process) input is presented to a built in Analogue to digital converter which converts the varying input voltages or currents to its digital representation which is then presented to the microprocessor for transmission using the method described above. In order to comply with the license regulations the number of conversions and transmissions per hour will be controlled by the microprocessor such that conversion and transmission cycles will operate on a timed basis or on an event (such as a switch closure). The receiver will decode the incoming signal as described above but in this instance the microprocessor will convert the digital data into an analogue format. An example would be using pulse width modulation which can resolved to an analogue voltage using a simple CR network or could be used, through a suitable current amplifier, to drive and provide speed control for an electric motor directly. .

Claims

Enhanced wireless remote control system Claims With this invention I

claim: (1) This system provides an instant, license free bi-directional wireless data communications and remote control system that does not require any specialist knowledge, beyond a basic understanding of electrical systems in order to create a low power and license free data communications system for controlling and receiving feedback from remote events.

(2) This system will provide error free communications, even in electrically noisy environments or alongside other systems using the same frequency.

(3) This system allows the user to create a wireless data communications system without having any knowledge of propagation or antenna design.

(4) This system allows the user to create a wireless data communications system without having any knowledge of communications protocols or communications methods.

(5) This system will allow the user to create a complex remote control system within a few minutes using a minimum of external components with little specialized knowledge.

(6) This system will provide excellent security and integrity by having a unique identifier for each matched transceiver pair.

(7) The modules in the system are capable of being used together with other modules to create customized systems.