52 lines
1.4 KiB
C++
52 lines
1.4 KiB
C++
#include <driver/adc.h>
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float battery_read()
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{
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//read battery voltage per %
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long sum = 0; // sum of samples taken
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float voltage = 0.0; // calculated voltage
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float output = 0.0; //output value
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const float battery_max = 3.6; //maximum voltage of battery
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const float battery_min = 3.3; //minimum voltage of battery before shutdown
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float R1 = 470000.0; // resistance of R1 (100K)
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float R2 = 470000.0; // resistance of R2 (10K)
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for (int i = 0; i < 500; i++)
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{
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sum += adc1_get_voltage(ADC1_CHANNEL_7);
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delayMicroseconds(1000);
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}
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Serial.print("Out :");
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Serial.println(sum);
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// calculate the voltage
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voltage = sum / (float)500;
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voltage = (voltage * 1.1) / 4096.0; //for internal 1.1v reference
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// use if added divider circuit
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voltage = voltage / (R2/(R1+R2));
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//round value by two precision
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voltage = roundf(voltage * 100) / 100;
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Serial.print("voltage: ");
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Serial.println(voltage, 2);
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output = ((voltage - battery_min) / (battery_max - battery_min)) * 100;
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if (output < 100)
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return output;
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else
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return 100.0f;
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}
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void setup()
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{
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adc1_config_width(ADC_WIDTH_12Bit);
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adc1_config_channel_atten(ADC1_CHANNEL_7, ADC_ATTEN_11db); //set reference voltage to internal
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Serial.begin(115200);
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}
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void loop()
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{
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Serial.print("Battery Level: ");
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Serial.println(battery_read(), 2);
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delay(1000);
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}
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