The simplest DIY actuator controller based on 51 single chip microcomputer

51 SCM Internet of things smart car series article catalog

Chapter one ： The most simple DIY Of 51 Bluetooth remote control car design
Second articles ： The most simple DIY Serial port Bluetooth hardware implementation scheme
Third articles ： The most simple DIY bluetooth PS2 The remote control controls the Bluetooth smart car
Fourth articles ： The most simple DIY be based on 51 Servo controller based on single chip microcomputer

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Preface

    daodanjishui The simplest of the core original technologies of the Internet of things DIY be based on 51 Servo controller based on single chip microcomputer .
     There are various open source intelligent steering gear controllers on the market , But there are complex and simple , If you want to get started quickly, it is based on 51 The servo controller of single chip microcomputer is matched with the intelligent car , This plan will give you a quick and efficient plan .

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One 、 The most simple DIY be based on 51 What is the actuator controller of single chip microcomputer ？

     In the first part, the design of Bluetooth remote control intelligent car is completed , Readers are curious about why there are in the source code PWM Control code ？ But I was too lazy to delete it when I was writing a blog , Take up one more IO Mouth won't make a mistake . Now it's my fourth blog post ：DIY be based on 51 Servo controller based on single chip microcomputer Buried the foreshadowing .
     Although there are many open source steering gear controller solutions on the market , But it is all controlled by register configuration PWM Wave output code is very few , Now write it down in words , This code was developed by guotianxiang 51 SCM books copied from . I didn't create it , Later, there will be an original 51 PTZ design launched .
     This time I use 51 SCM development board to do the steering gear control , It mainly uses the buttons above .
51 The SCM development board is as follows ：

Two 、 analysis

1. Prepare the hardware

1.1 Buy sg90 The steering gear （180 Steering gear ） As shown in the figure below ：

Complete the wiring between MCU and steering gear ：
sbit pwm =P2^7 ; //PWM Signal output , Connect the data cable of the steering gear
1.2 Get ready 51 Single chip microcomputer
Buy single chip microcomputer by yourself

2. Parsing code

     This 51 The code of single chip microcomputer is also quite simple , Although it is written in register , But it is also a very classic one PWM Wave generation procedure ！ The code is as follows , comparison arduino Control procedure of , This code is much more valuable ！ Later I will launch STM32 Version of the steering gear control program , In fact, it is also completed by using the idea of this program for reference .

#include "reg52.h"

unsigned char count; //0.5ms  Number identification 

sbit pwm =P2^7 ; //PWM Signal output , Connect the data cable of the steering gear 

sbit jia =P3^7; // Angle increase button 

sbit jan =P3^6; // Angle decrease button , Low level trigger 

unsigned char jd; // Angle identification  1.0ms->45 1.5->90 2.0->135 2.5->180

void delay(unsigned char i)// Ordinary delay function 

{
    

unsigned char j,k;

for(j=i;j>0;j--)

for(k=125;k>0;k--);

}

void Time0_Init() // Timer 0 initialization 

{
    

TMOD = 0x01; // Timer 0 Work in the way 1,16 Bit increment count timer ,16 All of them 1, The maximum count value is 65535, It overflowed 

IE = 0x82;//EA=1 Global interrupts allow ,ET0=1, Timer interrupt allows 

TH0 = 0xfe;//(65536-N)/256=0xef=254 Introduction N=512,N Is the number that needs to be counted , The machine cycle is 1.09us, therefore 

//512*1.09us=0.5ms, At this time, the steering gear is 0 degree ,1ms yes 45 degree ,2.5ms yes 180 degree , Other analogies 

TL0 = 0x33; //11.0592MHz Single chip microcomputer of crystal oscillator , Lead to 0.5ms The counter overflows once , Generate timer interrupt 

TR0=1; // Turn on timer 

}

void Time0_Int() interrupt 1 // Timer 0 Interrupt service routine 

{
    

TH0 = 0xfe; // Reload the initial value 

TL0 = 0x33;

if(count< jd) // Judge whether the counting times are less than the identification 

pwm=1; // Output high level PWM

else

pwm=0; // Low level PWM

count=(count+1); // Count times continue to increase 

count=count%40; // Count times must be less than 40, because 0.5ms*40=20ms, This is the steering gear PWM A fixed period of 

}

void keyscan() // Key scan 

{
    

if(jia==0) // Press the Add button 

{
    

delay(10); // Eliminate jitter 

if(jia==0) // Press the Add button 

{
    

jd++; // Logo added , Altogether 5 files ,jd=1 Corresponding 0 degree ,jd=2 Corresponding 0,45 degree ,jd=3 Corresponding 90,4 Corresponding 135,5 Corresponding 180 degree 

count=0; // Count clear 0, When count Add to 2 When , Overflow twice , Time is 0.5*2=1ms, Turn the corresponding steering gear to 45 degree 

if(jd==6)

jd=5; // Identification clear 0

while(jia==0); // Wait for the key to release 

}

}

if(jan==0) // Press the decrease button 

{
    

delay(10);

if(jan==0)

{
    

jd--; // Empathy 

count=0;

if(jd==0)

jd=1; // Reset 

while(jan==0);

}

}

}

void main()

{
    

jd=1;

count=0;

Time0_Init();

while(1)

{
    

keyscan(); // Dead cycle , Key detection 

}

}

3. Principle analysis of steering gear

According to how it works , The specific control method of the steering gear needs a 20ms Left and right time base pulses , The high level part of the pulse is generally 0.5ms_{2.5ms Angle control pulse part in range . The pulse width ranges from 0.5ms}2.5ms, The position of the corresponding rudder is 0~180 degree , It changes linearly . General steering gear pulse width 20ms, Correspondence between high level width and angle

0.5ms————0 degree ;

1.0ms————45 degree ;

1.5ms————90 degree ;

2.0ms————135 degree ;

2.5ms————180 degree ;
According to the above principle , We know that as long as a single-chip computer produces 20ms Pulse signal of , By changing the high level time from 0.5ms To 2.5ms change , The steering gear can be turned to the corresponding angle . Finally, the function of the program is to press the Add button , Steering gear from 0 C to 180 , Press 5 Time ; Steering gear from 180 To 0 Also need to press 5 Time reduction button .

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3、 ... and 、 Simulation and debugging

1. Get the hardware ready , Access to electricity .

The hardware connection is relatively simple .

2. Control the steering gear

Press the Add button , Steering gear from 0 C to 180 , Press 5 Time ; Steering gear from 180 To 0 Also need to press 5 Time reduction button .

summary

     Just learned 51 SCM readers had better get started with this code , Yes 51 There is a deep understanding of the use of SCM registers , It will lay a solid foundation for the future manipulator control and intelligent car speed regulation .

Download project code ：https://www.cirmall.com/circuit/20977/
Point, I'll jump