Traditional Chinese Practical Balance Sensory Detector: Circuit Design, Parts List & Workshop Prototype Guide

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Balance Sense TesterPrinciple of balance feeling detection: The tester wears a shaking sensor on his head, closes his eyes, stands on one foot, remains stationary, presses the test switch, and the instrument starts testing. The sensor sends out a pulse signal every time it detects shaking exceeding one degree, and the pulse signal is sent to the counter for accumulation. Once the specified test time is up, the instrument will give a prompt and stop counting. The cumulative value of the pulses displayed on the instrument is the tester's balance feeling index. Obviously, it is very interesting and meaningful for the balance feeling index detector to collect the balance index of different age groups and to collect the own balance index at different periods. For example, cardiovascular and cerebrovascular patients can use balance index to monitor their recovery status. The patient's balance index is higher during severe illness and lower after recovery.Circuit working principle: The balance feeling detection instrument is composed of three parts: a shaking sensor, a timing control unit and a counting unit, as shown in Figure 18-1. The shake sensor adopts the HY-9 photoelectric shake sensor developed by the Institute of Mechanics of Southeast University. Its detection range is ±90 degrees, the minimum resolution is one degree, and the characteristic frequency is 80Hz. That is, the sensor outputs a pulse signal to the counting unit every time it shakes one degree. alt="26.jpg (88643 bytes)">Figure 18-1There are many counting unit circuits. This article uses a four-bit counting integrated block (MM74C926). The circuit is simple and the maximum count is 9999. The integrated block has a multiplexer that drives the display inside. It only needs to be connected to the common cathode of the seven-segment LED display through four external switch tubes. The multiplex conversion frequency is about 1Hz. The timing control unit is composed of binary counter (MC4060) and D flip-flop and other gate circuits. The timing unit mainly completes the tasks of reset bit count and timing control. MC4060 contains an oscillator. CR determines the clock frequency of the oscillator. Q14, Q13, and Q12 are three-speed timing control outputs. After pressing the reset switch, MC4060 and MM74C926 are cleared, and the D flip-flop is set to Q high (Q low), then the counting gate is opened, the counter is in the counting (detection) state, and the counter increases by 1 for each pulse arrival. After the specified time, the timing control output generates a positive transition, the flip-flop is reversed, the Q output is low (Q is high), the counting gate is closed, the counter stops counting, Q controls the NAND gate, and drives the piezoelectric crystal to emit a "beep" prompt sound. At the same time, the state of the D flip-flop is locked until the reset switch is activated. The timing sequence of each point in the circuit is shown in Figure 18-2. The power consumption of the whole circuit is about 150mA. …

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