Patent Publication Number: US-5293161-A

Title: Selective call receiver having a variable frequency vibrator

Description:
This is a continuation of application Ser. No. 07/539,404, filed Jun. 18, 1990 now abandoned. 
    
    
     FIELD OF THE INVENTION 
     This invention relates in general to selective call receivers having a tactile alert, and more specifically to selective call receiver having a variable frequency vibrator. 
     BACKGROUND OF THE INVENTION 
     Electronic devices such as selective call receivers have different methods of alerting a user that a message has been received. One such method of alert is a tactile alert (e.g., vibrational alert), which is conveniently used in business meetings, libraries, and other places where it may be inappropriate to use an audio alert. However, in conventional selective call receivers, the frequency of the vibrator device is usually fixed at some pre-determined frequency. Although the frequency of vibration is fixed, a large variation in the frequency results from the manufacturing process. This causes some users, however, to consider the vibratory mode to be either too high or too low, and as a consequence, a number of these users may avoid using the vibratory alert mode. 
     Regrettably, however, a selective call receiver having a variable frequency tactile alert has been heretofore unavailable, thus failing to satisfy the varied needs of different users of selective call receivers. Accordingly, a need exits for a tactile alert having a variable frequency of vibration. 
     SUMMARY OF THE INVENTION 
     Briefly, according to the invention, a electronic device comprises a receiver for receiving a message and having a vibrator alert capable of vibrating at a selected one of at least two frequencies. The vibrator also has a selector capability for varying the frequency of the vibrator. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of a selective call receiver in accordance with a first embodiment of the present invention. 
     FIG. 2 is a block diagram of a selective call receiver in accordance with a second embodiment of the present invention. 
    
    
     DESCRIPTION OF A PREFERRED EMBODIMENT 
     Referring to FIG. 1, a selective call radio receiver 100 (e.g., a pager) comprises an antenna 102 that provides an RF carrier signal that is mixed with a local oscillator signal contained within the receiver module 104. The receiver module 104 generates a recovered signal suitable for processing by a decoder 106 in a manner well known to those skilled in the art. The decoder 106 converts the signal to an address. A controller 112 compares the decoded address with one or more predetermined addresses contained in the memory 108. When the addresses are substantially similar, the user is altered that a signal has been received by either by an audio alert (e.g., speaker) 114 or a tactile alert (e.g., vibrator) 116. 
     According to the invention, the frequency of the tactile alert 116 can be varied by varying a frequency selector 120. In this way another vibrating frequency of the tactile alter 116 may be selected. 
     In one embodiment, the frequency selector 120 comprises a microcomputer (the controller 112) programmed via conventional techniques to measure a parameter (e.g., the actual vibration, such as, the amplitude of vibration, or the electromagnetic force) of the tactile alert (vibrator alert) 116. Optionally, the microcomputer comprising the frequency selector 120 may monitor a signal, such as, the current or the voltage of the power supply 118, or the electromagnetic force of the tactile alert 116. This information is then used to keep the vibration of the tactile alter 116 substantially constant or at the desired frequency setting. According to the invention, a selected frequency of vibration is held substantially constant, for example, by the microcomputer of the controller 112, which monitors the current applied to vibrator from the power supply 118. As the battery power decreases (such as by aging) to the point where there is insufficient current to maintain the present frequency of vibration, the microcomputer will select another frequency of vibration such as by comparing the current used to a threshold stored in the memory 108. Other methods of choosing alternate frequencies of vibration may be, for example, according to the voltage supplied from the power supply 118 or the amplitude of vibration of the tactile alert 116. The electronic device capable of being powered by the power source providing an output that varies over a voltage range, and the controller providing a constant signal to the vibrator over the voltage range. 
     FIG. 2 shows a selective call receiver 100 similar to FIG. 1 and comprising a second embodiment for varying the frequency of the tactile alert 116. In this embodiment, the selective call receiver 100 includes a tuning hole on a housing (not shown) to permit tuning a tuning element 130 (e.g. a tunable resistor) that is monitored by the controller 112. The controller is responsive to the voltage monitored to vary the drive signal 132 to the tactile alert 116. The tuning hole may be located in any suitable location on the selective call receiver, such as, under a removable conventional belt clip, under the battery door on the housing, within a code plug programming slot, under a housing lock opening, or under labels etc. on the selective call receiver 100. 
     Accordingly, varying the current or voltage using known techniques may also be used to vary the frequency of the tactile alert 116, which in another aspect of the invention may be measured using one of the several known techniques, such as, frequency counters or pressure sensor feedback systems that are commercially available from manufactures such as TDK or Murata. After measuring the vibration of the tactile alert 116, information relating to the selected frequency may be displayed on the display 110 of the selective call receiver 100. 
     In summary, a variable frequency vibrator allows the user to preset a desired frequency of vibration. The present frequency is held constant by a microcomputer or the like the over an active range of the power supply, and after further discharge of the power supply 118 (e.g., below the active range), the microcomputer will measure a parameter from the power supply 118 or the tactile alter 116 to select the next suitable frequency of vibration. Additionally, the selective call receiver 100 may display the selected frequency of vibration setting on the display 110.