Wireless speed indicating system of automobile

[0001]

	5,818,332	Oct. 6, 1998	Yau Dang	340/441
	5,708,410	Jan. 13, 1998	Blank et al	340/438
	5,172,100	Dec. 15, 1992	Lino	345/7

[0002] Safe driving is top priority for automobile drivers. Collision frequently occurs while followed driver failed to notice sudden slowing down of vehicle in front. To dress this problem, some kind of automobile speed indicator has been developed. Yau Dang invented an automobile speed indicator using different color of light to indicate automobile speed. However, bad weather, limited vision may make driver of following automobile fails to notice the warning.

[0003] A wireless speed indicating system utilizes wireless means to transmit speed information of preceding automobile to the automobile just followed. Information of The speed change of preceding automobile is displayed before the driver of following automobile. Sound alarm is generated when preceding automobile is slowing down.

[0004] FIG. 1 shows transmitting of speed signal of preceding automobile to following automobile.

[0005] FIG. 2 shows function structure of one preferred embodiments of speed signal processing unit together with wireless transmitting device.

[0006] FIG. 3 shows function structure of one preferred embodiments of display unit together with wireless receiving device.

[0007] A wireless speed indicating system of automobile is invented. The indicating system is composed of a Speed Signal processing (SSP) unit, a Display (DP) unit, a transmitting device and a receiving device. As shown in FIG. 1, the SSP unit 1 and transmitting device 2 are installed at rear of an automobile. The SSP unit 1 processes speed signal coming from speed meter of automobile to determine if the automobile is speed-up, slowing-down or maintaining constant speed. The result is sent to the following automobile through transmitting device 2 such as directional transmitting antenna. The receiving device 4 such as directional receiving antenna and DP unit 5 are installed in the front of an automobile. The receiving device 4 receives signal 3 transmitted by preceding automobile and feeds it to DP unit 5. The DP unit 5 processes the received signal and displays the result. The transmission of speed information can be carried out by wireless means such as electromagnetic wave, infrared, laser or ultrasonic.

[0008] FIG. 2 shows one of preferred embodiments of the SSP unit. The SSP unit utilizes speed signal applied at speed meter of automobile as its input signal. This standard speed signal is 4000 pulses per mile. The speed signal of 4000 pulses/mile from automobile is applied to input of frequency/voltage (F/V) converter 6 to get related voltage signal. The higher the automobile speed, the higher output voltage of the F/V converter 6. The output of F/V converter 6 is applied to input of first sampling/holding (S/H) unit 7 that is used to sample and hold current automobile speed. The second sampling and holding (S/H) unit 8 samples and holds the output of first S/H unit 7. This value is previous automobile speed. The pulse generator 9 provides sampling pulses and controls sampling frequency. The time delay unit 10 is used to secure that first S/H unit 7 won't start sampling until second S/H unit 8 finishes sampling. The output of first S/H unit 7 (current automobile speed) and output of second S/H unit 8 (previous speed) are compared at comparator 11 and 14. Resistor 12 and 13 are used to attenuate output voltage (stand for current speed) of S/H unit 7. Resistor 15 and 16 are used to attenuate output voltage (stand for previous speed) of S/H unit 8. This attenuation generates dead zone for camparator 11 and 14. Radio frequency generator 17 generates two RF signals with different frequency f1 (first frequency) and f2 (second frequency). If attenuated current speed is higher than not-attenuated previous speed (automobile is speeding up), the comparator 11 will turn switch 18 on and RF signal of first frequency (fl) is sent to power amplifier 20. If attenuated current speed is lower than not-attenuated previous speed (automobile is not speeding up), the comparator 11 will turn switch 18 off and no RF signal of first frequency (f1) can be sent to power amplifier 20. If attenuated previous speed is higher than not-attenuated current speed (automobile is slowing down), the comparator 14 will turn switch 19 on and RF signal of second frequency (f2) is sent to power amplifier 20. If attenuated previous speed is lower than not-attenuated current speed (automobile is not slowing down), the comparator 14 will turn switch 19 off and no RF signal of second frequency (f2) can be sent to power amplifier 20. The RF signal from power amplifier 20 is transmitted out through transmitting antenna 2 to following automobile. The antenna is a directional antenna and the transmitted RF power is only effective within 40 meters from transmitting antenna 2 along the pointed direction of the antenna.

[0009] FIG. 3 shows a preferred embodiment of RD unit. The directional receiving antenna 4 picks only the RF signal pointed to it. The received signal is amplified by pre-amplifier 21 and then sent to frequency identifier 22. If the received signal is at first frequency (f1), the frequency identifier 22 turns on switch 23. The indicator 24 of first color, preferred to be green, will be on. It indicates that the automobile just ahead is speeding up. If received signal is at second frequency (f2), the frequency 22 turns on switch 25 and switch 28. Alarm generator 27 will drive speaker 29 to give out warning sound and indicator 26 of second color, preferred to be amber, will be on. It indicates that the automobile just ahead is slowing down. If no RF signal is received, switch 23, 25 and 28 are all off. Both green and amber light are off and no warning sound is generated. It indicates that the automobile just ahead is at constant speed.