How To Make Auto Ranging Ohm Meter

 How To Make Auto Ranging Ohm Meter

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Hello Dear, Welcome to the new blog. In this video tutorial, I will show you How to make an auto-ranging ohmmeter. These are really cool projects. You can measurement any resistor value without selecting any resistor range. The Parts required for this Project 1. Atmega 328p IC

2. 28 Pin IC Base

3. Transistor 2N2906x5

4. Resistor 1K, 10k, 100k, 1M, 2M

5. Resistor 10K x1

6. LED

7. HC05 Bluetooth Sensor

8. IC Base 28 Pin

9. AC Terminal Block 2pin x2

10. AC Terminal Block 3Pin

11. 22pf Capacitor

12. Variable Resistor

13. Female to Male IC Rail

14. Power Socket

15. 16Mhz Crystal

16. USB B Type

17. LCD 16x2

Circuit Diagram:

Code:

#include <LiquidCrystal.h> // include Arduino LCD library // LCD module connections (RS, E, D4, D5, D6, D7) LiquidCrystal lcd(2, 3, 4, 5, 6, 7); #define CH0 12 #define CH1 11 #define CH2 10 #define CH3 9 #define CH4 8 // variables byte ch_number; uint32_t res; const uint32_t res_table[5] = {100, 1000, 10000, 100000, 2000000}; char _buffer[11]; void setup(void) { Serial.begin(9600); lcd.begin(16, 2); // set up the LCD's number of columns and rows lcd.setCursor(0, 0); // move cursor to column 0, row 0 [position (0, 0)] lcd.print("Resistance ="); pinMode(CH0, OUTPUT); pinMode(CH1, OUTPUT); pinMode(CH2, OUTPUT); pinMode(CH3, OUTPUT); pinMode(CH4, OUTPUT); ch_number = 4; ch_select(ch_number); } // main loop void loop() { uint16_t volt_image = analogRead(A1) + 1; if(volt_image >= 550 && ch_number < 4) { ch_number++; ch_select(ch_number); delay(50); return; } if(volt_image <= 90 && ch_number > 0) { ch_number--; ch_select(ch_number); delay(50); return; } if(volt_image < 900) { float value = (float)volt_image*res/(1023 - volt_image); if(value < 1000.0) sprintf(_buffer, "%03u.%1u Ohm ", (uint16_t)value, (uint16_t)(value*10)%10); else if(value < 10000.0) sprintf(_buffer, "%1u.%03u kOhm", (uint16_t)(value/1000), (uint16_t)value%1000); else if(value < 100000.0) sprintf(_buffer, "%02u.%02u kOhm", (uint16_t)(value/1000), (uint16_t)(value/10)%100); else if(value < 1000000.0) sprintf(_buffer, "%03u.%1u kOhm", (uint16_t)(value/1000), (uint16_t)(value/100)%10); else sprintf(_buffer, "%1u.%03u MOhm", (uint16_t)(value/1000000), (uint16_t)(value/1000)%1000); } else sprintf(_buffer, "Over Load "); lcd.setCursor(0, 1); // move cursor to position (0, 1) lcd.print(_buffer); Serial.println(_buffer); Serial.println(); delay(500); // wait some time } void ch_select(byte n) { switch(n) { case 0: digitalWrite(CH0, LOW); digitalWrite(CH1, HIGH); digitalWrite(CH2, HIGH); digitalWrite(CH3, HIGH); digitalWrite(CH4, HIGH); break; case 1: digitalWrite(CH0, HIGH); digitalWrite(CH1, LOW); digitalWrite(CH2, HIGH); digitalWrite(CH3, HIGH); digitalWrite(CH4, HIGH); break; case 2: digitalWrite(CH0, HIGH); digitalWrite(CH1, HIGH); digitalWrite(CH2, LOW); digitalWrite(CH3, HIGH); digitalWrite(CH4, HIGH); break; case 3: digitalWrite(CH0, HIGH); digitalWrite(CH1, HIGH); digitalWrite(CH2, HIGH); digitalWrite(CH3, LOW); digitalWrite(CH4, HIGH); break; case 4: digitalWrite(CH0, HIGH); digitalWrite(CH1, HIGH); digitalWrite(CH2, HIGH); digitalWrite(CH3, HIGH); digitalWrite(CH4, LOW); } res = res_table[n]; }

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