JPS6314394B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a pedometer.

Among the purely mechanical devices that count and display the number of steps taken when walking or running, there is a pedometer, which is well known in the past. Fig. 1 shows an example of its configuration. 1 is a pendulum, 2 is a weight, 3 is a spring, 4 is a base plate, 5 is a pendulum fulcrum shaft, 6 is a gear, 7 is a feed piece, and 8 is a reverse prevention piece. , 9 is a spring fixing pin, 10 is a stopper, 11 is a case fixing part, 1
2 is a step count display board, and 13 is an indicator hand. Note that the arrow direction in the figure is vertically upward, and it is attached to a part of the body such as the waist. When the pendulum 1 swings up and down while walking or running, the gear 6 is sent one tooth at a time by the feeder 7 attached to the pendulum 1, and a mechanism connected to the gear 6 (not shown) ) to drive the indicator hand 13 and display the number of steps.

Next, Figure 2 shows a step sensor for a pedometer that does not use the gear mechanism mentioned above but counts electrically. are given the same reference numerals. The pendulum 1, weight 2, spring 3, pendulum fulcrum shaft 5, and spring fixing pin 9 are almost the same as those in FIG.
In addition, a permanent magnet 14 and a reed switch 15 are newly provided.

To explain the operation below, the pendulum 1 swings due to the vertical movement of the body associated with walking or running, and the pendulum 1
The permanent magnet 14 attached to the tip of the reed switch 15 swings up and down on the sides of the reed switch 15, and as the permanent magnet 14 approaches and moves away from the reed switch 15, the pendulum 1 is attached to both ends of the reed switch 15 up and down. Opening/closing signals corresponding to the movement can be obtained. The signal obtained from this reed switch is counted by a counter, and the value is displayed on a display or the like.

By the way, Figure 3A shows the vertical acceleration G versus time t during walking, and the vertical movement of the human body during walking or running does not result in a single sway, although it depends on the walking speed and individual differences. , 1 step (S ₁ in Fig. 3,
S ₂ indicates the time required for one step)). Therefore, the step sensor shown in Figure 2 in particular causes 1 to 3 vibrations as shown in Figure 3 (B).
A plurality of detection signals a from the reed switch 15 are generated in response to each step, which causes erroneous counting of the number of steps.

Additionally, a signal expansion circuit is provided between the step sensor and the counter to extend the detection signal for a certain period of time (for example, 130 [msec]), so that one detection signal is obtained for each step. According to this, for example, when walking at a speed of about 140 steps/minute, the detection signal is extended by one step as shown in Figure 4.
There are cases where the OFF time is less than 10 [msec] between a′ (hereinafter referred to as an expansion signal) and the next expansion signal, so when counting the detection signals using a microcomputer etc., these two This had the disadvantage that it could not be identified as a signal and was incorrectly counted as one step, resulting in a lower number of steps than the actual number of steps.

The present invention has been proposed in view of the above points, and its purpose is to connect a pulse width conversion circuit such as a monostable multivibrator to the rear stage of a signal expansion circuit that obtains one output signal per step. death,
To provide a pedometer which performs counting after converting the pulse width of an output signal from a signal expansion circuit into a fixed time period, thereby completely preventing erroneous counting especially when walking at high speed.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 5 is a circuit diagram showing one embodiment of the present invention, and its configuration can be roughly divided into a step count sensor 20, a signal expansion circuit 30, a pulse width conversion circuit 40, a counter 50, and a display 60. The step count sensor 20 includes a pendulum 22 having a magnet 21 attached to its tip so as to be swingable, and the pendulum 22 is held horizontally by a spring 23 in a stationary state. The pendulum 22 is arranged opposite to the magnet 21 at the tip, and turns ON when the magnet 21 approaches or moves away.
One end of the reed switch 24 to be turned off is connected to the positive electrode of the DC power supply E, and the other end is led to the signal extension circuit 30 as an output terminal of the step count sensor 20.
In the signal expansion circuit 30, the reed switch 24
The cathode of the diode D, whose anode is connected to the ground, is connected to the movable terminal of the changeover switch SW, which can be switched between walking and running, and the base of the transistor Tr ₁ whose emitter is grounded. is connected to through resistor _R3 . Furthermore, variable resistors R ₁ and R ₂ with one end grounded are connected to the fixed terminal of the changeover switch SW, and either of the variable resistances R ₁ or R ₂ is connected in parallel with the capacitor C by operating the changeover switch SW. It's becoming like that.

The collector of the transistor Tr ₁ is connected to the positive terminal of the DC power supply E via the resistor R ₄ , and the transistor Tr ₂ has its emitter connected to the positive terminal of the DC power supply E.
The collector of the transistor Tr 2 is connected to the base of the transistor Tr ₂ via a resistor R ₅ , and the collector of the transistor Tr 2 is grounded via a resistor R ₆ and is also connected to the subsequent pulse width conversion circuit 40 as an output terminal of the signal expansion circuit 30 . . This pulse width conversion circuit 40 is made of, for example, a monostable multivibrator, and is used to convert the pulse width of the output signal of the signal expansion circuit 30 into a fixed time period and output it. The output signal is counted and displayed as the number of steps by a subsequent counter 50 and display 60.

This operation will be explained with reference to the time chart shown in FIG. Here, in Figure 6 B, a~
It is assumed that each signal waveform indicated by e indicates a voltage change at each corresponding point in FIG.

First, as shown in Figure 6A, if two positive signals occur within the time required for one step when walking (indicated by S ₁ and S ₂ in the figure), as shown in Figure 6B, There is a normal pulse in the detection signal a of the step sensor 20.
P ₁ and an extra pulse P ₂ that causes false counting. This detection signal a is the changeover switch SW
The integration circuit formed by the variable resistor R ₁ or R ₂ and the capacitor C produces a waveform with a gentle trailing edge as shown in b. In the figure, V indicates the ON level of the transistor Tr _1. When the signal b falls below this level, the transistor Tr ₁ turns OFF, and the voltage at the collector point c changes to the H level.
If the constant of the integrator circuit is appropriately selected, the ON level v of transistor Tr ₁ will not fall below v after pulse P ₁ disappears and before pulse P ₂ is generated, and one pulse can be taken out for each step.
In addition, the expansion time T appearing in signal waveform b is a variable resistor.
By switching R ₁ and R ₂ and adjusting the resistance value, it is appropriate to set T = 130 [msec] when walking and 35 [msec] when running.

In addition, since the signal c is a negative pulse, it is inverted and amplified by the transistor Tr ₂ , and as shown in d, the pulse is
output signals. The output signal d of the signal expansion circuit 30 has an OFF time Δt between pulses when walking at a high speed of 140 steps/minute as described above.
is Δt≦10 [msec]. This output signal d is input to a pulse width conversion circuit 40, and is converted into a signal e having a pulse width of T' from the rising edge of the signal d. This pulse width T' is determined by the capacitor and resistor in the monostable multivibrator as the pulse width conversion circuit 40, and is between 50 and 100.
We are planning to select [msec]. Therefore, one output signal e with a relatively short pulse width and easy to identify is obtained from the pulse width conversion circuit 40 for each step, and this signal is accurately counted by the counter 50, and the counted value is Display 6 as number of steps
This is displayed by 0.

As described above, according to the present invention, a signal expansion circuit is provided downstream of the step count sensor to expand the detection signal of the step count sensor to obtain one pulse-like output signal for each step, and Since the pulse width of the output signal is converted into a fixed time using a pulse width conversion circuit and then counted using a counter,
In particular, even when walking at high speed, one signal is always input to the counter for each step.
This has the effect of completely preventing erroneous counts and providing a highly accurate pedometer.

[Brief explanation of the drawing]

Figure 1 A and B are explanatory diagrams of a pedometer, Figure 2 is an explanatory diagram of a conventional step sensor, Figure 3 A is a waveform diagram showing the relationship between time and vertical acceleration, and Figure B is a lead Figure 4A is a waveform diagram showing the relationship between time and vertical acceleration, Figure 4B is a time chart of the reed switch detection signal, Figure 4C is a time chart of the expansion signal,
5 is a circuit diagram showing an embodiment of the present invention, FIG. 6 A is a waveform diagram showing the relationship between time and vertical acceleration, and FIG. 6 B is a voltage waveform at each corresponding point in FIG. It is. 20...Pedometer, 30...Signal extension circuit,
40... Pulse width conversion circuit, 50... Counter.

Claims (1)

[Claims] 1. A step sensor that detects the vertical movement of a human body during walking and outputs a detection signal, a signal expansion circuit that appropriately expands the detection signal to obtain one pulse-shaped output signal for each step, and the signal expansion circuit. A pedometer comprising: a pulse width conversion circuit that converts the pulse width of an output signal of the circuit into a fixed time; and a counter that counts the output signal of the pulse width conversion circuit.