GB2482568A

GB2482568A - Device for driving unidirectional motors in bursts for enhanced data display

Info

Publication number: GB2482568A
Application number: GB1018838.1A
Authority: GB
Inventors: Richard George Hoptroff
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-11-08
Filing date: 2010-11-08
Publication date: 2012-02-08
Anticipated expiration: 2030-11-08
Also published as: GB2482568B; GB201018838D0

Abstract

A timepiece with a pointer, for example a hand, has a pulse generator configured to be in one of two states, each generating a different number of pulses. A driving circuit selects the state on comparison of an electronic data reference and a pointer position reference. A stepping motor drives the pointer according to the number of pulses. Thereby the position of the pointer can be corrected by varying the number of pulses.

Description

DEVICE FOR DRIVING UNIDIRECTIONAL MOTORS IN BURSTS FOR ENHANCED

DATA DISPLAY

This invention relates to the use of unidirectional watch and clock stepper motor drivers to indicate the progression of time. The invention pulses the motor in bursts in order to convey additional information that is either independent of the time indication or can be derived from it.

Clocks and watches display, primarily, the passage of time. A typical analogue electronic device uses a stepper motor that is excited at regular intervals. The constant rate of stepping is translated by means of gearing to a display based on moving elements such as pointers (e.g. hours, minutes and seconds hands) and plates (e.g. 31-day date window).

Such gearing is either rationally linear (i.e. elements move in repeating cycles with periodicities related by ratios of integers) or a step-wise derivative of the same (e.g. a date plate that steps one position at midnight).

One measure of state of the state of art of such electronic circuits may be regarded as US Patent 4014164, most commonly embodied in the PCA2000 integrated circuit produced by NXP Semiconductors. In normal operation, it produces one pulse per second. When the battery is low, it instead issues a burst of four pulses every four seconds. This alternate, regular pattern results in a stepping motion that is jerkier but maintains the basic time indication. The electronic circuit does not store a count of where it has moved the elements in the time display; it simply drives the motor according to a regular pattern. Consequently, the additional low battery' information is unarguably conveyed by the characteristics of the motion of the moving elements rather than their resulting positions.

This invention relates to a method of irregularly driving a stepper motor to convey extra information. US Patent 4271494 discloses a similar method to achieve similar goals, but requires a series of irregular pulses that alternately drive the motor forwards and backwards.

This invention differs in that it requires forward driving alone and deriving the desired result by a different mechanism and sequence of events. US Patent 4271494 does not consider this possibility despite it being possible to implement it using the circuit elements discussed in US Patent 4271494. Therefore it is reasonable to claim that the present invention is novel with respect to US Patent 4271494, and is not an obvious development from it.

According to a first aspect of the present invention, there is provided a timepiece, having a pointer, comprising a pulse generator, configured to be in a first state and a second state, wherein the pulse generator generates a first number of pulses in the first state and a second number of pulses in the second state, an electronic data reference, a pointer position reference, a driving circuit, including a number of pulses selector, wherein the number of pulses selector is configured to select the first or second state on comparison of the pointer position to the electronic data reference, and a stepping motor, configured to drive the pointer for the selected number of pulses.

According to a second aspect of the present invention, there is provided a method for driving a pointer on a timepiece, the timepiece having an electronic data reference, the method comprising the steps of comparing the position of the pointer to the electronic data reference, selecting a first number of pulses or a second number of pulses according to the comparison of the pointer position to the electronic data reference, and driving the pointer for the first or second number of pulses.

Accordingly, and with reference to figure 1, the invention is the following device: 1. An electronic circuit (101' in figure 1) drives unidirectional stepper motor (102'), which, possibly by means of gearing (103') drives mechanical display elements (104'), with reference to a regular timing component such as a crystal oscillator (105').

2. Electronic circuit (101') maintains an up-to-date count (106') of the time and the number of pulses imparted to the stepper (102').

3. The circuit generates stepper motor pulses in bursts which are sufficiently close to being regular in number over a long period of time that a regular progression of time is indicated by one or more moving elements, while the irregularities in the number of pulses in any one burst, derived at least in part from counter value (106'), conveys additional information according to the resulting position of the moving elements.

Embodiments of the invention would generally take the form of microcontrollers configured to count the moving element position and generate the irregular pulses required. The intent is to enhance the amount of information conveyed by existing watch and clock movements through the use of more sophisticated driving circuitry. Example embodiments include: 1. With reference to figures 1,2 and 3, motor driver circuitry (101') generates pulses to drive a stepper motor whose axis completes a rotation after 60 pulses and is connected to a second hand that completes a rotation every minute. In addition, it is connected to reduction gearing in the ratio 60:1. The resulting axis completes a rotation every 3600 pulses, or once per hour, and is connected to a minute hand.

This in turn is connected to reduction gearing in the ratio 12:1. The resulting axis completes a rotation every 43200 pulses, or once per twelve hours, and is connected to an hour hand.

Rather than generating pulses once per second as in a normal timepiece, motor driver circuitry (101'), with reference to counters (106'), generates bursts of pulses every minute (302' in fig 3). If 60 pulses are generated each minute, the hour and minute hands appear to advance normally in one minute steps to depict the time while the second hand comes to rest at the same position each time (201' to 202' in fig 2).

If 59 pulses rather than 60 are generated, the hour and minute hands appear to advance normally to depict the time while the second hand appears to have fallen back by six degrees (203'). If 61 pulses rather than 60 are generated, the hour and minute hands appear to advance normally in one minute steps to depict the time while the second hand appears to have advanced by six degrees. Thus the number of pulses generated each minute can control the depiction of an independent quantity on the pointer originally intended to depict seconds while depicting the passage of hours and minutes on the hours and minutes hands.

Motor driver circuitry (101') determines the value of the independent quantity to be displayed on an arc swept by the second hand (204'). It then determines (303') the number of pulses required to depict it as follows: If the resulting desired position of the indicator is within 3 degrees of the current position, 60 pulses are generated. If the resulting desired position of the indicator is between 3 to 9 degrees ahead of the current position, 61 pulses are generated, and for each 6 degree interval beyond that, a further pulse is generated. If the resulting desired position of the indicator is between 3 to 9 degrees behind the current position, 59 pulses are generated, and for each 6 degree interval beyond that, a further pulse is deducted from the number to be generated. The motor is then advanced that number of pulses accordingly (304').

2. With reference to figures 1, 4 and 5, motor driver circuitry (101') generates pulses to drive a stepper motor whose axis completes a rotation after 3600 pulses and is connected to a minute hand that completes a rotation every hour. In addition, it is connected to reduction gearing in the ratio 12:1. The resulting axis completes a rotation every 43200 pulses, or once per twelve hours, and is connected to an hour hand.

Rather than generating pulses once per second as in a normal timepiece, motor driver circuitry (101'), with reference to counters (106'), generates bursts of pulses once every two minutes (502' in fig 5). If 120 pulses are generated each two minutes, the hour and minute hands appear, overall, to advance normally in two-minute steps, i.e. the minute hand comes to rest each time is exactly 12 degrees ahead of where it was before (401' to 402' in fig 4).

If, on occasion, 60 pulses rather than 120 pulses are generated, the minute hand comes to rest 6 degrees ahead of where it was before. If the pattern then reverts back to 120 pulses, the hour and minute hands appear, overall, to advance normally to depict the time in two-minute steps while, when examined closely, minute hand is now 6 degrees behind (403').

If, on occasion, 180 pulses rather than 120 pulses are generated, the minute hand comes to rest 18 degrees ahead of where it was before. If the pattern then reverts back to 120 pulses, the hour and minute hands appear, overall, to advance normally to depict the time in two-minute steps while, when examined closely, minute hand is now 6 degrees ahead.

Motor driver circuitry (101') determines the value of the binary quantity to be displayed on alternately odd and even positions on the circle swept by the minute hand (404'). It then determines (503'), with reference to its count (106') of the number of pulses generated previously, the number of pulses required to depict the binary quantity as follows.

If the binary quantity is to remain unchanged, 120 pulses are generated (401' to 402'). If the binary quantity is to transition from the odd state to the even state, 60 pulses are generated. (402' to 403'). If the binary quantity is to transition from the even state to the odd state, 180 pulses are generated. The motor is then advanced that number of pulses accordingly (504').

Similar embodiments might indicate more detail than a binary secondary value. For example, a barometer might have three positions, "falling", "steady" and "rising".

Claims

CLAIMS1. A timepiece, having a pointer, comprising a pulse generator, configured to be in a first state and a second state, wherein the pulse generator generates a first number of pulses in the first state and a second number of pulses in the second state; an electronic data reference; a pointer position reference; a driving circuit, including a number of pulses selector, wherein the number of pulses selector is configured to select the first or second state on comparison of the pointer position to the electronic data reference; and a stepping motor, configured to drive the pointer for the selected number of pulses.
2. A timepiece according to Claim 1, wherein the timepiece has a plurality of time markings and the pointer is configured to point in either a clockwise or anticlockwise direction of the time marking to indicate ante meridiem or post meridiem, the electronic data reference being an electronic time reference.
3. A timepiece as claimed in any one of the preceding claims, wherein the pointer position reference includes a pointer position sensor.
4. A timepiece as claimed in any one of Claims 1 to 2, wherein the pointer position reference is set by the user.
5. A timepiece as claimed in either Claim 3 or Claim 4, wherein the pointer position reference is configured to receive a pulse at the first frequency from the pulse generator, such that the pointer position reference is updated.
6. A method for driving a pointer on a timepiece, the timepiece having an electronic data reference, the method comprising the steps of: comparing the position of the pointer to the electronic data reference; selecting a first number of pulses or a second number of pulses according to the comparison of the pointer position to the electronic data reference; and driving the pointer for the first or second number of pulses.
7. A timepiece substantially as herein described with reference to and as shown in any combination of the accompanying drawings.
8. A method substantially as herein described with reference to and as shown in any combination of the accompanying drawings.Amendments to the claims have been filed as follows * 9CLAIMS1. A timepiece, having a first pointer for indicating hour, minute or second information, comprising a second pointer for indicating additional information; a pulse generator, configured to be in a first state and a second state, wherein the pulse generator generates a first number of pulses in the first state and a second number of pulses in the second state; an electronic data reference; a second pointer position reference; a driving circuit, including a number of pulses selector, wherein the number of pulses selector is configured to select the first or second state on comparison of the second pointer position to the electronic data reference; and a stepping motor, configured to drive the second pointer for the selected number of pulses such that the second pointer indicates the additional information.2. A timepiece according to Claim 1, wherein the timepiece has a plurality of time markings and the second pointer is configured to point in either a clockwise or anticlockwise direction of the time marking to indicate ante meridiem or post meridiem, the electronic data reference being an electronic time reference.S* 5S5 * S * * 3. A timepiece as claimed in any one of the preceding claims, wherein the second * pointer position reference includes a second pointer position sensor. SS' * S4. A timepiece as claimed in any one of Claims I to 2, wherein the second pointer position reference is set by the user.5. A timepiece as claimed in either Claim 3 or Claim 4, wherein the second pointer position reference is configured to receive a pulse at the first frequency from the pulse generator, such that the second pointer position reference is updated.6. A method for driving a timepiece for indicating additional information, the timepiece having a first pointer for indicating hour, minute or second information, a second pointer for indicating additional information, and an electronic data reference, the method comprising the steps of: comparing the position of the second pointer to the electronic data reference; selecting a first number of pulses or a second number of pulses according to the comparison of the second pointer position to the electronic data reference; and driving the second pointer for the first or second number of pulses such that the second pointer indicates the additional information.7. A timepiece substantially as herein described with reference to and as shown in any * .... combination of the accompanying drawings.* 8. A method substantially as herein described with reference to and as shown in any *..*.S * * *: combination of the accompanying drawings.*.**I* * S