GB2315145A - Password-protected electronic time switch - Google Patents

Abstract

An electronic time switch whose settings can only be altered after a valid password has been entered. Power is supplied to the connected appliance/equipment only when the time is between presettable on and off times. Further control is provided such that power is only supplied to the appliance/equipment for a presettable period subject to the first control criterion. All settings of the time switch including the password are user-selectable and are entered on 1 and displayed on 2. Further information about the operational status of the time switch is provided by 3,4,5 and 6 and an internal audible sounder. The time switch sounds an audible warning when disconnection of the electrical supply to the appliance by the time switch is imminent and all the settings are protected if the supply to the time switch is interrupted.

Description

PASSWORD-PROTECTED ELECTRONIC TIME This invention relates to a password-protected electronic time switch.

Time switches (both electro-mechanical and electronic) are very familiar equipment, which enable the user to provide an electrical power supply to electricallelectronic apparatus at predetermined times only.

Existing time switches do not prevent unauthorised changes being made to their settings, nor do they provide the facility to control the total amount of time for which the connected apparatus is supplied with electrical power.

According to the present invention there is provided an electonic time switch to tum on and off the electrical supply to an appliancelequipment at user-selectable times wherein before the on/off time and all other settings can be made or altered, the correct user-selectable password must be entered.

The preferred embodiment of the invention also provides for the user to preset the total time duration for which the controlled appliancelequipment is to receive an electrical supply and in addition wams the user when disconnection of the electrical supply to the controlled appliance/equipment is imminent - though of course other embodiments might not include these features. The prefered embodiment of the invention uses a 12-key keypad for entering all settings of the invention, two 7-segment LED (light emmitting diode) digital displays for displaying the settings and four LEDs plus an audible indicator to provide various informationlwamings about the status of the invention; other embodiments could either omit some or all of these or implement the functions differently. Also, the preferred embodiment is housed in a two-part plastic case as illustrated in Figure 3, Figure 4 and Figure 5, and has an integral BSl 363-type 13Amp plug so that the appliance/equipment's supply cable is wired directly to the invention in place of the normal plug. In this embodiment the two halves of the case are joined together with security fasteners to prevent unauthorised removal of the invention from the supply cable of the appliance/equipment which it controls. For simplicity the join between the two parts of the case is not shown in Figure 3, Figure 4 and Figure 5, and nor is the method of fixing together the two parts of the case. Other embodiments of the invention could be housed differently, or could be part of another equipment or vehicle, or the wiring of a building. The preferred embodiment of the invention will now be described in detail, by way of example only, with reference to the accompanying drawings and appendices in which: Figure 1 & Figure 2 show the schematic diagrams of the electronic circuit. The appliancelequipment to be controlled is labelled as LOAD in Figure 1 and the phase and neutral connections to the mains electricity supply are labelled L and N respectively; Figure 3 shows the front view of the assembled invention; Figure 4 shows the top view of the assembled invention; Figure 5 shows a side view of the assembled invention; Appendix 1 describes the electronic components referred to in Figure 1 8 Figure 2; Appendix 2 shows the listing of the program which must be programmed into the microprocessor integrated circuit IC1 in Figure 1 to enable the invention to operate as described.

Referring to Figure 3, Figure 4 and Figure 5, the invention has a keypad 1, on which all settings for the invention are made; a two-digit display 2; four light emmitting diode indicators (LEDs) 3,4,5 and 6; a recessed push switch 7; and a BS1363 type 13Amp plug 8. The appliance/equipment's supply cable 9 is also shown. In order for the invention to be used for the first time, the power supply cable of the appliance/equipment to be controlled must first be wired to the invention and 8 must then be plugged into a source of approximately 230 Volt AC electricity such as the domestic mains supply. Since this is the first time the invention has been used, the user's own password has not been programmed into the invention and so the preset password must be enabled (this password has been permanently programmed into the micmcontroller integrated circuit IC1 in Figure 1). To do this the recessed push button 7 and the * key 10 on 1 must be pressed simultaneously and 7 released before 10. The preset password must now be entened on 1. Whenever the user enters a password a short delay between key presses is possible but if too long a delay occurs an audible waming is sounded and the user must enter it again from the beginning. If the entered password is incorrect another audible waming is sounded and the user must reenter the password from the beginning again. If the correct password has been entered, a third audible signal is produced. Until the correct password has been entered the invention cannot be used. Once the user has programmed in their own password (see below), all that is necessary for the user to change settings on the invention is that they enter their own password correctly. Should the user forget their own password, the preset one can be enabled again at any time by pressing 10 and 7 together as described above.

When the correct password has been entered one of five setting modes can be selected by repeatedly pressing the # key 11 on 1. The first press causes 3 to be illuminated and this indicates that the total on-time setting mode has been chosen. A second press causes 4 to light, indicating that the time-window setting mode has been chosen. A third press lights 5, indicating that the clock setting mode has been chosen. Another press illuminates 6, indicating that the password setting mode has been chosen. A further press causes 3,4,5 and 6 to light, showing that the override mode has been chosen. If 11 is pressed again just 3 stays lit, showing that the on-time setting mode has been selected again and, thereafter, repeatedly pressing 11 cycles the invention continually through its five setting modes. Before a setting mode can be used 10 must first be pressed. Each setting mode will now be explained in detail.

TOTAL ON-TIME SETTING MODE This enables the user to set the total amount of time for which power is to be supplied to the appliance/equipment. After 10 has been pressed to enable this mode, 3 flashes and an audible indication is generated which alerts the user that the hours part of this total time is being displayed on 2. The user can then enter on 1 the desired number of hours or, alternatively, press 10 again. In either case the minutes part of the total time is then displayed on 2, and 3 continues to flash but the audible indication ceases. Once again a new setting can be entered on 1 after which 2 displays the hours setting again and the audible indication sounds. By repeatedley pressing 10, 2 displays altemately the hours and minutes part of the total on-time setting. To exit this mode 11 must be pressed, after which the next mode is automatically chosen: TIME-WINDOW SETTING MODE This comprises two parts: the lower-limit and the upper-limit. Power can only be supplied to the appliance/equipment when the time is between these limits (and the on-time duration is not zero). After 10 has been pressed to enable this mode, 4 flashes and an audible indication is generated to tell the user that the lower-limit hours are being displayed on 2. A new setting can be entered on 1 or 10 pressed to display the lower-limit minutes. In either case, 4 continues to flash, but the audible indication ceases. Similarly a new minutes setting can be entered or 10 pressed again. In either case, the upper-limit hours are then displayed on 2 and a different audible waming alerts the user to this. As with the on-time setting mode, entering new settings or pressing 10 steps the invention through each of the four settings. To exit this mode 11 must be pressed, after which the next mode is automatically chosen: CLOCK SETTING MODE This mode is for setting the invention's own intemal clock, which it uses to compare with the time-window settings. After enabling this mode, by pressing 10, the mode works exactly like the time setting mode and is exited by a press of 11, which selects the next setting mode: PASSWORD SETTING MODE This enables the user to set their own password, so oveniding the preset password mentioned earlier. Pressing 10 enables this mode and displays on 2 the first digit of the password, an audible indication is generated and 6 flashes. Ether new password digits can be entered or 10 pressed to step through the digits of the password. While 6 continues to flash, whichever digit is being displayed on 2, the audible indication only sounds when the first digit is being shown. Pressing 11 exits this mode and selects the next one: OVERRIDE MODE This is not a setting mode and selection of this mode is indicated by 3,4,5 and 6 being lit. If the zero key 12 is pressed when this mode is selected, the invention immediately enters override mode. In this mode the invention supplies power to the appliance/equipment continuously, irrespective of the on-time duration remaining and the time-window settings and 3,4,5 and 6 flash on and off slowly to alert the user that the invention is in override mode.

Provided override mode has not been selected, pressing 12 puts the invention into its normal mode, in which it supplies power to the apliance/equipment only if the remaining on-time duration is not zero, and then only when the time is between the lower and upper window limits. When in this state 2 displays the remaining time - the left-hand digit indicating hours and the right-hand digit indicating ten-minute periods remaining - and decrements whenever the invention is in its normal mode and is supplying electricity to the appliance/equipment and the appliance/equipment is tumed on. When disconnection of the supply to the appliance/equipment by the invention is imminent, the invention generates an audible waming: when ten minutes or less time remains before the supply to the appliance/equipment is disconnected, a short audible 'beep' is sounded every ten seconds until one minute or less remains, when a long audible 'beep' is sounded every ten seconds.

When in normal mode 3,4,5 and 6 remain lit constantly.

When in override mode pressing 11 puts the invention into its normal mode.

Once the intemal battery is fully charged (by leaving the invention plugged into the mains supply for about 24 hours), if the mains supply to the invention is disconnected the invention retains all the user-entered settings and its intemal clock continues to run normally for up to 30 hours.

Claims (10)

1 An electronic time switch to tum on and off the electrical supply to an appliance/equipment at user-selectable times wherein before the on/off time and all other settings can be made or altered, the correct user-selectable password must be entered.

2 An electronic time switch as claimed in Claim 1 wherein the total time duration for which power will be supplied to the appliance/equipment is user-selectable after entry of the correct user-selectable password.

3 An electronic time switch as claimed in Claim 1 or Claim 2 wherein settings are entered on a 12digit keypad.

4 An electronic time switch as claimed in Claim 1 or Claim 2 wherein settings are entered by means other than a 12 digit keypad.

5 An electronic time switch as claimed in Claim 1, Claim 2, Claim 3 or Claim 4 wherein entered settings and current values of these settings are displayed on a two-digit 7-segment display.

6 An electronic time switch as daimed in Claim 1, Claim 2, Claim 3 or Claim 4 wherein entered settings and current values of these settings are displayed on a one-or-more-digit electronic display of any type.

7 An electronic time switch as claimed in Claim 1, Claim 2, Claim 3, Claim 4, Claim 5 or Claim 6 wherein additional information about the operational status of the time switch is given by additional visual or audible indicators.

8 An electronic time switch as claimed in Claim 1, Claim 2, Claim 3, Claim 4, Claim 5, Claim 6 or Claim 7 intended to be installed as part of the electrical equipment of a building or vehicle.

9 An electronic time switch as claimed in Claim 1, Claim 2, Claim 3, Claim 4, Claim 5, Claim 6 or Claim 7 intended for portable use whether permanently fitted to an appliance/equipment or not.

10 An electronic time switch substantially as described herein with reference to the accompanying Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Appendix I and Appendix 2.