Abstract:
A power distribution and timing device (PDTD) for controlling power supply to controlled device(s). This invention includes: an outlet; an alarm clock; a backup battery; a keyboard; a tamper switch; a display for showing day, time, modes of operation, programming steps, operational time remaining, warning signals and tamper attempts; and a microprocessor. The microprocessor includes: an integrated circuit for setting maintenance power to the controlled device(s); a program for securely programming the days and time periods when the controlled device(s) may be operated and the amount of time that the controlled device(s) may be operated; securely allowing power to the controlled device(s) to be increased to operating level when these time periods are not exceeded; and keeping power to the controlled devices at maintenance level when these time periods are exceeded. One or more of the outlets may be remote from the microprocessor and signals may be sent to such remote outlets via conventional means.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to the management of the play or operation of one of more controlled devices, and, in particular, to a method and apparatus for controlling when and for how long each day such device(s) may be played. 
   2. Brief Description of the Related Art 
   Children in developed nations typically have unlimited access to electronic devices, e.g., television, gaming devices and consoles, personal computers, etc., that may not always contribute to their positive growth and development. Parents and educators have noted a rise in childhood obesity and may not always agree with the beliefs promoted by television programs and video games. Access to electronic devices is almost impossible to control when children are at home without parents or guardians. Access to electronic devices is actually difficult to control even when parents and guardians are at home. First, parents and guardians must be in the same room where their children are using the devices. When a parent or guardian estimates that any of their children are spending too much time utilizing any of these devices, they may be forced to discipline the child. Since the amount of time on these devices is rarely measured, discipline occurs at inconsistent times, generally dependent on the mood of the parent, and generally without objective information to support the discipline. As a result, discipline without any data creates a strain on the parent-child relationship, often yielding poor results. 
   A secondary problem that exists is the fact that, when entertainment device use is unlimited, children value it less. When it is limited, for example if a child can only spend 10 hours per week watching television, television viewing will become a more valued, and therefore more planned, use of time. Therefore, instead of the practice of “flipping” through television channels, children will be more likely to select a planned schedule of certain television programs, which will result in a more valuable entertainment experience. 
   The automatic control of a variety of multiple electronic devices and appliances is well known in the art. U.S. Patent Application Publication 2004/0060059 is directed to a method and apparatus for remotely controlling a plurality of devices. This apparatus includes a control mechanism which is in communication with multiple devices or software programs, applications, processes, or sub-processes resident on the devices. The control mechanism is in communication with the input mechanism. The input mechanism may include an alphanumeric keypad, touch-activated display device, or other devices capable of accepting input from a user and transmitting this input to the control mechanism. The control mechanism is also in communication with a visual display mechanism. The control mechanism may be located in a dedicated housing, together with the input mechanism and the visual display mechanism which may be mounted thereon. In alternative embodiments, the control mechanism may exist as a program on a separate device, such as a television set, a personal computer, a hand-held computer, a computing device, etc. 
   In the preferred embodiment, the apparatus includes a control mechanism having a memory and a configurable database. This configurable database allows for the input, modification, deletion, and output of various variable and values, namely, multiple user accounts, device identification values unique to each device, and device usage allotment values for each device corresponding to the device identification value for each user account. The control mechanism further includes a user interface which would allow the parent or guardian to set the settings for each user (child). In the preferred embodiment, the control mechanism allows for user names, user types, week day hours, weekend hours, password changing, bonus allowances, use restriction, user deletion, device selection, time or date selection and modification, time carryover options, hours per device, setup password changing, user statistics, etc. 
   U.S. Pat. No. 5,964,661 is directed to an apparatus and method for timing video games. The video game timer is interposed between the video game power supply and the video game console. The video game timer serves to interrupt the power supply to the video game console. The video game timer is plugged into the power input jack of the video game console and the video game power supply is plugged into the power input jack of the video game timer. A solid state switch of the video game timer, turns the power to the video game unit on and off. This switch is controlled by a microcontroller in the video game timer, as shown in. The microcontroller further polls to determine if there are any inputs from the twelve key keyboard and keeps track of time from a twenty-four hour counter. A small audio transducer is used to provide feedback to the user, specifically a tone is transmitted in response to input on keyboard and the audio transducer also provides a warning beep five seconds before power is turned off to the video game console. 
   U.S. Pat. No. 4,510,623 is directed to a television channel lockout. The microprocessor controls the channel which the television is tuned into. The microprocessor receives commands from the user via the control panel keyboard or the remote transmitter. When a keyboard entry is made, microprocessor checks to determine whether the four-digit master key has been entered. If not, the microprocessor then checks to determine whether the channel has been entered. If not, the microprocessor checks the EPROM to determine if the entered channel bit is “high” indicating that the channel is locked out. If that channel is not locked out, the microprocessor mutes the audio, blanks the channel number display and loads the PLL with the required programmable constant for the channel number selected. If the channel selected was a locked out channel, the flow diagram proceeds from connector A in A to the same connector in B. Having determined that the channel selected is a locked out channel, the microprocessor causes the display to blink the selected channel number for five seconds. If during that time, no four-digit code is entered or the correct four-digit security code is not entered, microprocessor will cause the display to display the last channel number and then go into the idle mode. A locked out channel cannot be watched for the next twelve hours unless the correct four-digit security code is used. 
   U.S. Pat. No. 5,654,746 is directed to a secure authorization and control method and apparatus for a game delivery service. The transaction control unit (TCU) receives transaction data from a decoder, interprets received transactions and performs other functions. The TCU further includes RAM and ROM memory. It further manages the authorization maps and operates game timers. The various game timers include parental control, playtime and the like, and may be decremented in ten second intervals. 
   U.S. Pat. No. 6,722,984 is directed to a game controller with parental control functionality. One implementation of a parental time limit feature includes setting a parental limit flow chart and monitoring and limiting play time flow chart. In this example, the limit is expressed as a maximum number of hours per day that the game controller may be used. The controller counts down the time that is actively in use via an algorithm that assumes that a ten-second period without any button press activity means that the unit is no longer active. When the countdown value reaches zero, the controller no longer responds to button presses. At the start of each new day, the daily limit value is automatically reinstated to the parentally set value. Further, the system may provide a “warning” signal such as a beep or a flashing LED a short interval prior to complete expiration of the limit value. Further, a small LCD display could be provided on the controller to show remaining time allocation. 
   U.S. Pat. No. 5,125,492, U.S. Pat. No. 5,497,479, U.S. Pat. No. 5,541,664, U.S. Pat. No. 5,716,273, U.S. Pat. No. 5,845,260, U.S. Pat. No. 5,973,683, U.S. Pat. No. 6,433,831, U.S. Pat. No. 6,519,208, U.S. Pat. No. 6,704,929, U.S. Patent Application No. 2002/0075760, and U.S. Patent Application No. 2003/0056209 are all directed to similar systems 
   Development of a power distribution and timing device which can control the time period and total time that a controlled device can operate each day, provide maintenance power to the device, and securely prevent tampering with the device represents a great improvement in the field play time control and satisfies a long felt need of parents and guardians 
   SUMMARY OF THE INVENTION 
   The present invention is a power distribution and timing device (PDTD) for controlling power supply to controlled device(s). This invention includes: an outlet for (a) accepting a power plug and cord from, and (b) supplying power to the controlled device(s); an alarm clock for alerting a user when a pre-set time has been reached; a backup battery for providing power to the PDTD when the PDTD is disconnected from mains power; a keyboard for allowing entry of a security code and programming of the PDTD; a tamper circuit and tamper switch for detecting when the PDTD has been tampered with; a display for showing day, time, modes of operation, programming steps, operational time remaining, warning signals and tamper attempts; and a microprocessor. 
   The microprocessor includes: 
   an integrated circuit for setting for setting maximum allowable power draw (maintenance level) when the controlled device(s) is/are not operating; 
   a program for: 
   securely programming the days and time periods (allowable time period) when the controlled device(s) may be operated and the amount of time (total time) that the controlled device(s) may be operated (normal operation mode); 
   securely allowing power to the controlled device(s) to be increased to operating level (override mode); and 
   securely keeping power to the controlled device(s) to maintenance level (restrict mode); 
   an integrated circuit for setting, turning on and turning off the alarm clock; 
   an integrated cicuit for recharging the backup battery as needed when the PDTD is connected to mains; and 
   an integrated circuit for: 
   determining the mode of the program; 
   if the mode is normal operation mode:
         if the current day and time are within the allowable time period and the total time has not been exceeded, allowing power to the controlled device(s) to increase to operating level, detecting that current draw has been increased to operating level, and decrementing the count down timer whenever a user turns the controlled device(s) on;   as the current day and time approaches the end of the allowable time period, issuing a warning signal;   as the end of the total time period approaches, issuing a warning signal;   at the end of the allowable time period, decreasing power to the controlled device(s) to maintenance level; and   at the end of the total time period, decreasing power to the controlled device(s) to maintenance level;   if the program is in override mode, allowing power to the controlled device(s) to increase to operating level; and   if the program is in restrict mode, keeping power to the controlled device(s) at maintenance level;       

   When the power cord is disassemblable from the controlled device(s), i.e. the power cord has a second plug which plugs into a receptacle on the device(s), the invention further comprises an additional means for indicating whether the power cord has been disassembled from the controlled device(s). 
   An appreciation of the other aims and objectives of the present invention and an understanding of it may be achieved by referring to the accompanying drawings and description of a preferred embodiment. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front perspective view of this invention showing the case, the display and the keypad. 
       FIG. 2  is a real perspective view of this invention with the rear door open and showing the electrical receptacles and tamper switch. 
       FIG. 3  is a block diagram of the most important elements of this invention. 
       FIG. 4  illustrates the display and keypad of this invention  FIG. 5  is a flow chart showing initial set up of this invention. 
       FIG. 6  is a flow chart showing the various programming functions that can be programmed for this invention. 
       FIG. 7  is a flow chart showing the three modes of operation of this invention. 
       FIG. 8  is a flow chart illustrating what happens if the invention is tampered with. 
       FIG. 9  is a flow chart illustrating programming a new code into the invention. 
       FIG. 10  is a flow chart illustrating setting of the clock. 
       FIG. 11  is a flow chart illustrating the various methods for programming of the timer. 
       FIG. 12  is a flow chart showing how to set the alarm feature of the invention. 
       FIG. 13  is a flow chart showing programming of the timer to allow the same on/off times and the same total time for each day. 
       FIG. 14  is a flow chart showing programming of the timer to allow different on/off times and the different total times for each day. 
       FIG. 15  is a flow chart showing how operation of the invention may be overridden: i.e. unrestricted operation of a connected device is allowed. 
       FIG. 16  is a flow chart showing how operation of the invention may be restricted: i.e. no operation of a connected device is allowed. 
       FIG. 17  is a flow chart illustrating the tamper evident seal of this invention. 
       FIG. 18  is a sketch showing use of the tamper evident seal of this invention. 
       FIG. 19  is a sketch illustrating an alternate embodiment of this invention comprising a PDTD which controls one or more devices at a distance from the PTDT. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility. 
   Referring to  FIGS. 1 ,  2  and  3 , it will be seen that this invention  10  comprises a microprocessor  14  connected to a keyboard  18 , a display  22 , a tamper switch  26  and a receptacle  30 . Power is supplied to the microprocessor either from the mains, via a plug  34  and power cord  38 , or from a rechargeable, backup battery  42 . Any kind of commercially available tamper switch  26  (such as a reed switch, or spring loaded switch) can be used. The invention  10  is contained within a case  46  which includes a rear, receptacle access door  50 . The case  46  is assembled with tamper proof screws (not illustrated). Tamper proof screws are well known in the art. The head of a tamper proof screw is designed so that it can be inserted with a common screwdriver but not removed with a common screwdriver. 
   The door  50  is attached to the case  46  with a hinge  54  and co-operates with the tamper switch  26  to provide a tamper signal to the microprocessor  14 . The device whose operation it is desired to control (controlled device)  58  is plugged in to the receptacle  30  within the case  46  via a plug  70  and power cord  66 . The door  50  has a keyway  62  so that the power cord  66  for the controlled device  58  can exit the case  46  while its plug  70  is trapped behind the closed door  50 . The preferred embodiment of this invention  10  will control a single device  58 . An alternate embodiment  10  will have several receptacles  30  for controlling several devices  58 . 
   The microprocessor  14 : contains a default security code, operational program, day and time clock, and countdown timer; controls the display  22 ; allows reprogramming of the security code and operational program; allows for the clock to be securely set; starts and stops the timer; senses current to the controlled device  58 ; supplies maintenance power to the controlled device  58 ; switches power to operational level for the controlled device  58 ; detects opening of the tamper switch  26  via a tamper circuit; provides visible (via the display  22 ) and audible alerts; controls charging of the backup battery  42 ; allows programming of the alarm clock; and controls functioning of the alarm clock. Programming includes normal, restrict and override operation. Alerts include tamper, end of time limit and end of total time alerts. 
     FIG. 4  illustrates the display  22  and keyboard  18 . The functions of the buttons on the keyboard  18  are self evident and will become clearer from the description below. The display is preferably a backlit LCD display  22 . The backlight remains on low intensity at all times for easy viewing at night and switches to high intensity during programming, alarm and alert modes, and whenever a controlled device  50  is being used. 
   Each function or mode is indicated in the display  22  and will begin to blink along with the corresponding characters when their programming is enabled. It will be clear that not all the markings on the display  22  are visible at all times. The markings that are visible at any time will become clearer from the description below. 
   A. Initialization 
     FIG. 5  illustrates initializing the invention. To start, the controlled device(s)  58  are turned off. Then they are plugged into the receptacle(s)  30  and the plug compartment door  50  is closed. The PDTD  10  is plugged into mains and the current day and time are set. See B2 below. At this point, the unit  10  determines maintenance power. It is well known that many electrical devices draw a small amount of power when off in order to minimize the time it takes to turn on the device, keep LEDs lit, keep backup batteries charged, maintain clock settings, etc. For purposes of this invention, maintenance power is defined the current draw of the controlled device(s)  58  when they are turned off plus a small tolerance. The tolerance is preferably +5 to 15% to allow for fluctuations in line voltage. The unit  10  always supplies this maintenance power to the controlled device(s)  58 . The circuit that determines current draw with the devices  50  off is simply an amp meter. The maintenance power is shown on the display  22 . Then the unit  10  can be programmed (see B) or operated (see C). In addition the alarm may be set (see D). 
   B. Programming 
   A valid security code is required to enter programming mode. Functions are active and can be modified when they are blinking in the Display. The (+) (−) keys are used to adjust the programming forward or back and up or down. Pressing and releasing the (+) or (−) keys momentarily provides slow adjustments while holding the keys down will scroll the digits quickly. Any time any button is pressed on the keyboard the display goes from dim to bright in order to aid visibility. In addition all button presses are confirmed with an audible tone. 
   The ENTER key must always be pressed after final adjustment to confirm the last entry or to scroll to the next function. If there is no activity for one minute, programming will time-out: this will require starting again.  FIG. 6  illustrates the different kinds of programming that can be accomplished.
         1. Changing Security Code. The unit  10  is provided with a default four digit security code which is preferably “1234”. For maximum security the default security code should be changed when the unit  10  is initialized. The new security code is, preferably, a four digit permutation of the numbers 1, 2, 3 and 4. More digits and higher numbers could easily be utilized for this invention but 256 different security codes are available with the preferred scheme. This plus the security features make having more than 256 different possibilities unnecessary. Preferably, a four digit number that is easy for the controlling party (the parent) to remember should be used and this should be changed frequently. To change the security code, the steps outlined in  FIG. 9  are followed.   2. Setting the Clock. The clock is set and reset using the procedure shown on  FIG. 10 .   3. Setting the Timer. The microprocessor contains a default timer program, preferably as follows:       

   
     
       
             
             
             
           
             
             
             
             
           
         
             
                 
                 
             
             
                 
               Allowable Time Period 
                 
             
           
        
         
             
               Day 
               Start Time 
               End Time 
               Total Time 
             
             
                 
             
             
               Sun 
               7:30 AM 
               8:30 PM 
               4 Hours 
             
             
               Mon 
               3:30 PM 
               8:30 PM 
               1 Hour 30 Minutes 
             
             
               Tue 
               3:30 PM 
               8:30 PM 
               1 Hour 30 Minutes 
             
             
               Wed 
               3:30 PM 
               8:30 PM 
               1 Hour 30 Minutes 
             
             
               Thu 
               3:30 PM 
               8:30 PM 
               1 Hour 30 Minutes 
             
             
               Fri 
               2:30 PM 
               11:00 PM  
               4 Hours 
             
             
               Sat 
               7:30 AM 
               11:00 PM  
               4 Hours 
             
             
                 
             
           
        
       
     
   
   Alternatively the microprocessor  14  can be reprogrammed with a new timer program. The PDTD can be programmed with the same start and end times and total playtime for each day or programmed with varying start time, end time and total time for each day. 
   Pressing the TIMER key selects between the three operational modes of the Timer: Auto, Restrict, and Override. See  FIG. 11 . Auto mode allows operation during the allowable time periods and up to maximum total time. Auto mode is entered after following the programming steps of  FIG. 13  or  14 . Restrict mode allows no operation of the device(s) at all and is entered after following the programming steps of  FIG. 16 . Override mode allows unlimited operation of the device(s) and is entered by following the programming steps of  FIG. 15 . 
   4. Alarm. Only the Alarm function can be programmed without the 4-digit security Code. Press the ALARM key once to display the current alarm set time. The displayed alarm time will be blinking and can be adjusted by using the (+) (−) keys. Each subsequent press of the ALARM key will toggle between ON and OFF on the display. See  FIG. 12 . 
   C. Normal Operation 
   There are three separate programs running simultaneously: Clock, Timer, and Alarm. Normal operation proceeds as shown in  FIG. 7  depending on what operational mode has been pre-programmed. Operational power to the device(s)  58  is only provided during the allowable time period each day and then only for the total time programmed. 
   Thus operation of the device(s)  58  can only commence between the programmed start and end times each day. The timer will begin the count down sequence when a controlled device  58  is switched on during an allowable time period. If the device  58  is turned off during the period, the timer will cease timing. The display  22  will continually display the clock time for ten seconds and then operational time remaining for three seconds between the start and end time. 
   When the timer approaches total time or end time an alert signal will be issued. Preferably the alert signal is flashing of the LCD backlight on the display  22  and sounding of an audible alarm. Preferably this will occur during the last 5 minutes remaining on the countdown timer. Preferably the frequency of the alerts will increase as the remaining time approaches 0:00. The following is the preferred schedule: 
   4:59–3:00 minutes remaining—alerts every 30 seconds 
   2:59–1:00 minutes remaining—alerts every 15 seconds 
   0:59–0:00 minutes remaining—alerts every 5 seconds. 
   Following this schedule allows the user to wind up operation of the device, saving progress on a game or computer, ejecting CDs, etc. 
   When end time is reached or total time reaches 0:00 for that day, the PDTD  10  will cease providing operational power to the device(s)  58  and revert to providing maintenance power. 
   D. Tamper Operation 
   The unit  10  will go into tamper mode if the plug compartment door  50  is opened, thus triggering the tamper switch  26 , or if an invalid code is entered during programming. Tamper operation is shown in  FIG. 8 . The plug compartment is electronically and mechanically tamper protected even during long-term power outages. Mechanical tamper protection is provided by the tamper proof screws which are used to assemble the case  46  as described above. 
   Upon opening the compartment door  50 : the device will switch into Restrict mode and the display will begin to blink the Restrict and Tamper messages. A valid security Code is required to reset the display and return the Unit to normal operation. 
   When invalid codes are entered the microprocessor counts the number of attempts. When invalid codes are entered for the first and second times, an alert signal is issued. Preferably the alert signal is that Code, Tamper and Restrict messages and the LCD will begin to blink alternately between high and low intensity in the display  22 . In addition on the third attempt the keyboard is locked for 1 minute. When an invalid code is entered for a fourth or subsequent time, the keyboard will be locked for 24 hours. 
   If the code has been forgotten or is not known the unit  10  must be reset. The only way to reset the invention  10  is to unplug the unit  10  from power and allow approximately 10 days for the backup battery to become depleted. After this, when power is reapplied all default settings will be restored and the backup battery will be re-charged. 
   E. Tamper Evident Seals 
   Most computers, printers, some televisions, etc. have removable power cords  66 . This would allow unplugging of the device  58  and connection directly to mains with an alternate power cord thus defeating the tamper protection of this invention  10 . Therefore, this invention is further provided with a tamper evident seal  80 . A number of such seals  80  are illustrated in  FIG. 17 . The seals  80  are an adhesive backed film (Preferably of plastic or paper) provided on a release paper  82  with a hole  84  through which the power cord  66  fits and a slit  88  running from the hole  84  to the edge  92  of the seal  80 . The seal  80  is peeled off the release paper and fastened to the device  58  around the cord  66  and plug  96  as illustrated on  FIG. 18 . The seals  80  are made of a frangible film with an extremely high tack adhesive. The seals  80  may be printed with appropriate warnings and may contain a box  100  for the control person to annotate with initials or signature as an added measure of security. Any attempt to remove a seal  80  will result in destruction of the seal  80 . It will readily be appreciated that a device  58  may not be unplugged without destroying the seal. 
   Thus it can be seen that this invention  10  allows a controlling party (e.g. a parent) to control when and for how long a user (e.g. a child) can operate a controlled device  58  (e.g. a television). All the controlling party has to do is plug the controlled device  58  into this invention  10 , close the door  50 , change the code, program the current day and time, and then program the time periods when the controlled device  58  can be operated and total time(s) for which the device  58  can be operated during each time period. In addition, if the device  58  can be disassembled from its power cord  66 , the controlling party can affix a tamper evident seal  80 , around the cord  66  and plug  96 , where the cord  66  plugs into the device  58 . Further, the user can program the device  10  so that it can function like a regular alarm clock. 
   Moreover, if desired and for the purpose of rewarding the child, the parent can put the PDTD  10  into override mode and thus allow the child to unlimited play with the controlled device(s)  58 . If necessary and for discouraging or punishing bad behavior, the parent can put the PDTD  10  into restrict mode and thus disallow any play with the controlled device(s)  58 . 
     FIG. 19  illustrates an alternate embodiment of this invention  10 . In this embodiment the PTDT  110  has one or more transmitters  114  instead of one or more receptacles  30 . These transmitters  114  based on the programming described above, transmit an ON or OFF signal to a remote control  118 . The remote control  118  plugs into mains via an outlet  34 . In turn the device  58  plugs into a receptacle  30  in the remote. Preferably the signal transmitted from the transmitter  114  to the remote  118  is radio frequency. This would require the transmitter  114  to be a radio transmitter and the receiver  118  to be a radio receiver. The technology for secure transmission and reception of radio signals is well known and used in currently available WIFI devices, for example. Alternatively, the signal would be transmitted over standard house wiring. The technology for secure transmission and reception of signals over standard house wiring is also well known. A wide variety of products is currently available from X10, of Kent, Wash., for example. Of course, it would be easy for a user to remove the plug  70  from the receptacle  30  in the receiver  118 , remove the receiver  118  from the wall outlet  34 , and simply plug the device directly into the wall outlet  34 . Thus a tamper evident seal  80  is placed around the plug  70  to ensure that it is not removed from the receiver  118 . 
   The following reference numerals are used on  FIGS. 1 through 19 : 
     10  Power distribution and timing device (PDTD) 
     14  Microprocessor 
     18  Keypad 
     22  Display 
     26  Tamper switch 
     30  Receptacle 
     34  Power plug for PDTD 
     38  Power cord for PDTD 
     42  Backup battery 
     46  Case 
     50  Receptacle compartment door 
     54  Hinge 
     58  Controlled device 
     62  Keyway or slot in door 
     66  Power cord for controlled device 
     70  Power plug for controlled device 
     80  Tamper evident seal 
     82  Release paper 
     84  Hole in seal 
     88  Slit in seal 
     92  Edge of seal 
     96  Disassembable power plug for device 
     100  Writing area on seal 
     110  Alternate embodiment of PDTD 
     114  Transmitter 
     118  Receiver 
   The following definitions are used in this application: 
   allowable time period—the period of time each day that the controlled device may be operated; 
   controlled device—a device that is controlled by this invention; 
   control person, control party, parent or guardian—the person who controls usage of the controlled device(s); i.e. the person who knows the security code, securely connects the controlled device(s) and programs the PDTD; 
   LCD—liquid crystal display; 
   LED—light emitting diode; 
   maintenance level or power—the level of power that all the devices controlled by this invention draw when they are OFF, plus a small tolerance; 
   operational level or power—the level of power that all the devices controlled by this invention draw when they are ON; 
   PDTD—power distribution and timing device, this invention; 
   play—operation of controlled device(s) 
   tamper proof screw—screw that can be inserted with a regular screwdriver but cannot be removed; 
   tamper switch—a switch whose state (open or closed) changes when an adjacent element (such as a surface or a magnet) is moved adjacent to or a short distance away from the switch; 
   total time—the time that the devices controlled by this invention may be operated during the allowable time period; and 
   user, child—the person whose use of the controlled device(s) is controlled. 
   Thus, the present invention has been described herein with reference to a particular embodiment for a particular application. Those having ordinary skill in the art and access to the present teachings will recognize additional modifications, applications and embodiments within the scope thereof. 
   It is therefore intended by the appended claims to cover any and all such applications, modifications and embodiments within the scope of the present invention.