Measure the voltage with analog input (taking Arduino as an example, the range is about 1KV)

Statement ： I am a freshman majoring in Vehicle Engineering , The technical level of posting is not high , And this method has long been shared , This post only shares one experience , Please do not carry out some dangerous operations according to the content of this post , In case of accident , Nothing to do with me ！

Premise of instructions ：

   arduino Of A0、A1、、 The waiting port is the analog signal input port ,arduino The board is measured A0 The potential of the mouth A0 Port data , The range of pressure measurement is 0~5V, The resulting value is 0~1023. When measuring potential with analog input , The negative pole of the tested object shall be connected with GND Connect , Otherwise, it cannot be measured , And a series of wrong values are generated due to floating .

The core idea ：

       1、arduino Read voltage function of analog input .

       2、 Resistance partial voltage of series resistor .

       3、 The analog input value is calculated to obtain the voltage value .

example ：

The left side is the serial port monitor output value , On the right is the measured value of voltmeter .

The design of this example is 0~1030V Measuring circuit of measuring range .     

 

  Circuit diagram ：

Just look at the picture on the left , The right side is a little messy .

 

 

      Because the resistance is often not as accurate as the value measured by the mark or multimeter , therefore , The design of the circuit should be flexible . We can connect a variable resistor in series on the circuit to adjust the test accuracy . There is another way to adjust the accuracy , That is, modify some parameters in the calculation program , The value in this example has been debugged like this .

    About the choice of variable resistance , Total value of personal suggestions 10k Ohmic , At the time of calculation , It can be calculated by making the large partial voltage resistance take a value slightly smaller than the actual value , After that, it is compensated by sliding rheostat . such as 47k resistance , Value for 45k Calculate , If it is not enough, it can be compensated by adjusting the value resistance .

Calculation ：

        We know that the resistance partial voltage ratio of the series resistance is directly proportional to the resistance specific range , So we can calculate our original 5v How many times has the range been enlarged .

  Be careful ： We mentioned earlier that the resistance of electronic components is not completely accurate , So there is a problem in the value of resistance , Subsequently, the variable resistance and adjustment value will be used to calibrate , So this is a rough calculation .

Program ：

      If only one voltage is measured , The procedure is very simple , But when designing other projects , If you want to measure the voltage somewhere , This method can be used .

void setup() {
pinMode(A0,INPUT);                       // Make A0 For analog input 
Serial.begin(9600);  
}

void loop() {
int i =analogRead(A0);                   // Make A0 Port readout voltage , But this is 0~1023 The number of .
float V=0.00;           
Serial.print("  i=");  
Serial.print(i);                         // Efferent i Size .
V=i*(5.00/1023.00)*206.00;               //206.00 Is the magnification of the test voltage ( Adjust according to the actual situation , The original number is 205.55)
Serial.print("  V="); Serial.println(V); // Outgoing voltage V Size 
delay(100);                    
}

      This procedure will A0 Oral value i And the final calculation result V Output to computer , among i*（5.00/1023.00） It's to make A0 Mouth measured 0~1023 The number of becomes the actual measured voltage （ This operation can also be used map Function mapping implementation ）. after , Multiply 206.00（ Magnification ） You can get the voltage at the pressure measuring end V.

calibration ：

It is also mentioned repeatedly above , We leave elastic space in circuit design . Here is a brief description of the specific operation ：

1, Using variable resistance . After connecting the circuit , Adjust the variable resistance to 0, Then the pressure measuring end is connected to the measured object , At the same time, the measured object is connected to a finished voltmeter ,arduino Connecting to a computer , And turn on the serial monitor . Observe the value of the finished voltmeter and the... Returned from the serial port monitor V value . Adjust the variable resistance repeatedly , Until the two readings are basically consistent . Try more groups .

2,（ It's not necessary ） If the adjustment through variable resistance is still not calibrated , You can modify the multiple we calculated above .

Final , We can make arduino Calculate the exact value , however , Definitely not 100% accurate . The following figure shows some of my pressure measurement results .

The first group

 

 

  The second group

 

 

 

 

The third group