[ 0013 ] fig1 is a representation of an animal trap display system including a central display unit 101 having a receiving antenna 103 and a display board 149 including a list of animal trap identities 105 in association with a list of trap states 107 . as shown , each trap identity e . g . 109 is associated with a pair of light emitting diodes ( led ) 111 of different colors . for example , one led 113 on the left is green to indicate that the associated trap remains set and a second led 115 is red to indicate that the associated trap needs attention . also included in the system of fig1 is a plurality of animal traps 1 through n of which trap 1 is assigned reference numeral 117 and trap n is assigned reference numeral 119 . each trap 117 through 119 includes a trap sensor 121 ( fig2 ) and a wireless transmitter in addition to the normal trap mechanism 125 as shown in fig2 . the trap mechanism in fig2 is a standard household rodent trap , however , other trap mechanisms might be employed . the trap may be a humane trap of the cage variety with a closing door or a more rugged outdoor variety of the clamp trap such as the type used to capture fur bearing animals such as bear and mink . the only requirement of the trap mechanism is that a detector should be able to sense that the trap has been sprung or that the trap contains one or more captured animals . in the following embodiment , the trap is shown and described as a household rodent trap commonly called a mouse trap . the trap includes a movable portion 122 which is used in the normal manner to trap animals . [ 0015 ] fig3 represents the electrical circuit associated with the traps 117 - 119 . such circuitry may be embedded within the trap body as shown in fig2 or separate therefrom provided that the circuitry can sense the state of the trap . in fig3 the sensor 121 is represented as a single pole single throw switch 127 which is connected to a controller 129 . the sensor 121 may be mechanically , magnetically , electrically or optically coupled to the moving portion 122 of the trap . the exact nature of the sensor is not critical to applicant &# 39 ; s invention . also shown is a transmitter 133 with an associated antenna 135 . the transmitter is of a type well known in the art which am modulates a carrier frequency to transmit signals . it should be mentioned that the transmitters of all of the traps 117 - 119 transmit at the same carrier frequency in the present embodiment , however , such is not required . also included in the transmitter system of fig3 are an identity code storage 137 and a battery 131 . the code stored by storage 137 is unique to a particular trap so that the code can be decoded at a receiver to identify which trap is transmitting . in the present embodiment , thirty two traps 117 - 119 are possible so the identity code should comprise at least 5 binary digits ( bits ). other numbers of traps can be used in other embodiments and codes of different length are necessary . the controller 129 periodically reads the state of sensor switch 127 and transmits a message including the code of the transmitting trap and the then present state of the trap . additionally , the controller senses each change of state of the trap and transmits a signal within a few seconds of the change of state to contemporaneously signal the new state to a control unit . a block diagram of the central display unit 101 is shown in fig4 . a receiver 141 of the central display unit is tuned to receive the rf transmissions from the traps 117 - 119 and to connect the code and trap state received in those transmissions to a processor 143 which may be a programmed micro processor having a memory 145 . memory 145 stores the program and data for controlling the processor and may consist of a plurality of memory circuits including rom for the program and non - volatile ram for storing certain trap related data . also stored in memory 145 is a data table having an entry for each trap 117 - 119 which stores the last look state of the trap and the identification code representing the trap . the table of trap data is represented in fig5 as 147 . display unit 101 also includes a display section 149 comprising the pair of leds for each trap and a printed designation for the associated trap . as shown in fig4 thirty two trap designations are arranged in a column and the associated pair of leds e . g . 113 and 115 are arranged in a row with the trap designations . in addition , the central unit 101 may be equipped to provide trap state data to remote locations when the animal trap identifying system is not readily available . when so equipped , the system includes remote communication unit 146 which is advised of each trap state change detected by processor 143 . upon being advised , the remote communication 146 dials a preset telephone number to alert a human operator or initiates an automatic e mail message to the operator . each trap includes a code storage device 137 to store the unique code of the trap . this storage device 137 may be a permanently written code in the rom of controller 129 or in the present embodiment in a multi position dip switch . the user sets the positions of the dip switches of each trap to a different combination of positions . the display unit 101 includes a learn mode switch 153 connected to the processor 143 which , when depressed by the user , causes processor 143 to enter the learn mode . in the learn mode , which may last for 10 - 20 seconds , the processor receives a code and state transmitted from a trap and checks each trap entry of table 147 to see if the received code is being used by another trap . when the code is not already in use and thus is not stored in table 147 the new code is so stored in the next available position of trap table and both leds associated with that first available entry are flashed to alert the user of a successful learning operation . when an already in use code is received during a learn operation , such is identified by the check of codes and no leds are flashed . learning mode operation is described in detail in u . s . pat . no . 4 , 750 , 118 which is hereby incorporated by reference , and is generally well known in the art . the present embodiment includes dip switches in the traps and learning of identity codes by the display unit , however , other methods for trap identification could be used . for example , the traps and display could be sold as a set and each trap identity fixed in the trap and permanently memorized by the display unit . [ 0020 ] fig6 is a flow diagram of the operation of the trap transmitters 123 during normal operation . the flow begins with a start operation 161 which is initiated by the placement of batteries 131 into the trap . start operations generally comprise those initialization operations normally performed by a processor on power up . after the start is completed , the flow proceeds to a block 163 in which the state of switch 127 is read and assigned to a variable new_state . flow then proceeds to store the new_state in a block 165 and the new state is compared with a variable old_state which is stored by controller 129 . it should be apparent that an old state represents the state of switch 127 and thus movable trap portion 122 during a last check of trap status . when new_state equals old_state , no current state change has occurred and flow proceeds to block 169 to determine whether two minutes has expired since the last transmission . when two minutes has not passed , flow proceeds to a pause block 171 which is used to delay the excursions through the program loop represented by fig6 . during the pause other processor functions may be performed . after the pause which may only be for 0 . 5 seconds , for example , flow proceeds back to block 163 . when the decision step 169 determines that 2 minutes has passed since the last transmission , flow proceeds to block 173 where a 2 minute timer is reset and on to block 175 in which the identity code of the device is read from storage 137 and both the identity code and new state are transmitted via transmitter 133 and antenna 135 . after such transmission , the variable old_state is set to new_state in block 177 and flow continues to the pause block 171 and back to the program loop discussed above . similarly , when the performance of decision block 167 determines that new_state and old_state are not equal flow proceeds to the transmit step 175 where the identity code of the trap and the new_state are transmitted as before . from the above it can be seen that the trap continues to test for a state change and for the expiration of two minutes . when either event occurs , the trap code and then present state of the movable portion are rf transmitted and the process continues . in the display unit , the processor continues to scan for received codes . when a valid code is received , it is successively compared with the codes stored in table 147 to identify which trap sent the code . when the trap is identified , memory 145 table 147 for the just received trap code is updated to represent the new_state of the trap . processor 143 also performs a continuous loop to read the states of the traps 117 - 119 from memory 145 and energize the appropriate led e . g . 113 to visually represent the trap state . when operating as above described , a baited trap will continue to send a state indication that the trap is ready for use . when an animal takes the bait and springs the trap , the movable portion 122 of the trap moves to catch the animal . the sensor 121 will detect the movement of the movable member and when controller 129 next reads the sensor a signal will be sent to the display unit to reflect the state change . alternatively , as long as the trap remains unsprung and the movable portion does not move the transmitter 133 will be used every 2 minutes to notify the display unit that the state has not changed .
an arrangement for displaying the state of a plurality of animal traps is disclosed . each trap senses the position of a movable trapping portion such as a trap door or jaw and rf transmits the state of the movable portion . a display unit receives the rf transmissions from the traps and identifies and displays the then current state of each trap . the rf signals may be periodically sent from the traps and / or they may be sent in response to a change in state of the movable portion .