Chip: 74HC14D

The working voltage of 3.3 V to 5 V

Output mode of digital signal (pulse signal)

Detection way of infrared ray interrupts

Detection signal detected the obstacles for high level, no obstacle or beyond detection range output low level

LED two road Status indicator, indicator light ray interrupt, ray conduction indicator

Connection mode:

1. + 5

+ 5 the positive input port for the power supply, can be connected to 3.3 V ~ 5 V voltage

2. The GND

GND for power negative input port

3. The OUT

OUT for the signal output, link MCU I/O port, general external interrupt

Note: the for arduino players should set the MCU I/O ports for the input mode/receiving mode, otherwise unable to use.

Other MCU, or more advanced control panel, such as Arm these, if need to set the I/O port as the input and output model, must be

Set to input mode/receive, otherwise unable to use.

51 series microcontroller can directly use, do not need to set the input and output model.

Program design.

Speed measuring module OUT link in the MCU external fracture, whenever there is a infrared ray conduction is an external buffer.

Logic design.

Measuring range:

Speed sensor output pulse signal, a pulse interrupt once;Infrared ray conduction time is low level, so we set the interrupt to be low

Touch the law level pattern.General integer grid encoder, whether it is a principle of how many, in fact, such as 10 grid encoder, there are ten empty

Grid, after one revolution of the motor is ray conduction 10 times, external touch low level 10 times;

Install the ideas above, we can play the effect of speed sensor, we know that 10 interrupt a circle, so we calculation

Number and the total number of except at 10 number of rotation of the motor, and then according to the perimeter of the wheel, calculate how long the wheel is a circle, you can

In order to determine the car has run far.

Measuring speed:

According to the thinking of the distance measurement, we use a MCU timer, 1 seconds to receive how many external interrupt, for example, a second received 20

External interrupt, we can judge the car speed for 1 second car wheels turn two laps, and then calculate the perimeter of the car wheels, can be learned

The speed of the car for 1 second.