Based on STC8G2K64S4 single-chip microcomputer to display analog photosensitive analog value through OLED screen

#Foreword

This article mainly explains how to use the OLED screen to display the analog value detected by the analog light sensor

For how to use the OLED screen, please refer toBased on STC8G2K64S4 microcontroller to control OLED screen through I2C hardware

Finally, I won't be bothered by the photosensitive threshold and the light factor of the venue. The first two times were because of this, and then the consecutive start failed and it split directly in situ.Use the OLED display to display the analog values ​​to observe the parameters more intuitively, and then modify the threshold values ​​in the program

Hardware aspects

The main control board and OLED continue to use the last one, so I won't introduce it here. If you don't understand, you can read the article I mentioned above

The analog photosensitive is used here, and there are many treasures.The main difference from digital is that it will be smaller, there is no adjustable resistance, and the price will be relatively lower

As the name suggests, the analog photosensitive does not output a digital quantity, that is to say, it is not a simple 0 and 1, but an output analog value.In fact, the digital photosensitive is to add an adjustable rheostat on the principle of analog quantity to determine a value as the dividing line, and then compare the analog value with the dividing line, if it is greater than the dividing line, it will output 1; if it is less than the dividing line, the output will be 0

Let's talk about color first. Of course, there is no big problem with normal black and white. If there is light yellow or red, it is likely to be judged as white, which will lead to tracking problems.Although there are adjustable resistors, you can adjust the level of the dividing line, but you can't see it directly. Maybe it can be detected by a multimeter or other methods, but it greatly increases the time

Furthermore, there is the problem of the site. The ambient light at the scene is basically different from the ambient light that I debugged in the school. This will also cause the analog value of black or white to cross the dividing line, and all are judged as one color.If this happens in the three minutes of preparation before the game, it will explode directly

So the use of analog photosensitive can solve all the above problems, and the tracking part will basically not have problems

Software aspects

The analog value cannot be directly seen in the program, and it needs to be converted into an analog value through ad.

Note here that the pin of the analog photosensitive OUT must be connected to the pin of the microcontroller with adc function, not the common io port.This also depends on the chip

The principle is that the analog light sensor detects the voltage, and then the pin of the microcontroller needs to convert this voltage into an analog value, the formula is as follows

a //Analog valuev //Measured voltagevrsf //reference voltage256 //8-bit precisiona=v/vref*256

vrsf is generally explained in the chip manual, different chips are different.In STC8G2K64S4, it is connected with vcc, so it is 5V

Accuracy is easy to understand. The larger the number of digits, the more accurate it is. Generally, there are 9 and 10 digits to choose from

The next step is to display the analog value with OLED, and also use the library function of Zhufei Technology

Initialize adc:

adc_init(ADC_P06,ADC_SYSclk_DIV_2); //Select P06 as ADC function, ADC clock frequency is SYSclk/2

Digital display of analog values:

void gewei() //One digit display{int yushu;yushu=q%10;if(yushu == 1)one(2,47);if(yushu == 2)two(2,47);if(yushu == 3)three(2,47);if(yushu == 4)four(2,47);if(yushu == 5)five(2,47);if(yushu == 6)six(2,47);if(yushu == 7)seven(2,47);if(yushu == 8)eight(2,47);if(yushu == 9)nine(2,47);if(yushu == 0)zero(2,47);}void shiwei() //Ten display{int yushu;yushu=q/10%10;if(yushu == 1)one(2,40);if(yushu == 2)two(2,40);if(yushu == 3)three(2,40);if(yushu == 4)four(2,40);if(yushu == 5)five(2,40);if(yushu == 6)six(2,40);if(yushu == 7)seven(2,40);if(yushu == 8)eight(2,40);if(yushu == 9)nine(2,40);if(yushu == 0)zero(2,40);}void baiwei() //Hundreds display{int yushu;yushu=q/100%10;if(yushu == 1)one(2,33);if(yushu == 2)two(2,33);if(yushu == 3)three(2,33);if(yushu == 4)four(2,33);if(yushu == 5)five(2,33);if(yushu == 6)six(2,33);if(yushu == 7)seven(2,33);if(yushu == 8)eight(2,33);if(yushu == 9)nine(2,33);if(yushu == 0)zero(2,33);}

Main code:

#include "headfile.h"int q;void main(){DisableGlobalIRQ(); //Close the total interruptboard_init(); //Initialize internal registers, do not delete this code.init_all(); //Initialize all functionsEnableGlobalIRQ(); //Enable global interruptpingmu_init(); //Screen initializationxianshi(); //Open the screen displaywhile(1){q = adc_once(ADC_P06, ADC_10BIT); //collect ADC once, precision 10 bitsgewei(); //display unitsshiwei(); //display tensbaiwei(); //display hundredspca_delay_ms(10);}}

Please refer to the OLED code hereBased on STC8G2K64S4 microcontroller to control OLED screen through I2C hardware

Effect display:

#Summary

I believe that in future competitions, the photosensitive tracking will be very stable, and I will not panic because of insufficient time on site.Although it is not a very powerful thing, it may be very useful.In terms of code, there are still many sub-functions that need to be optimized. Once these things are done, it will be more convenient in the subsequent use process

I am a novice, I have questions to exchange and discuss, and be taught with an open mind