Code and wiring for display temperature from ds18b20 on 7 segments display with ATtiny85
The resistor between DS18B20 data and VCC is idealy 4.7K Ohms but it can be everything between 4.7K and 5.3K Ohms.
- DS18B20 (interpreteur): DallasTemperature
- DS18B20 (Communication): OneWire
- 7-segments (TM1637): TM1637
#include <OneWire.h>
#include <DallasTemperature.h>
#include <TM1637Display.h>- ONE_WIRE_BUS = DS18B20 pin
- CLK = TM1637 Clock pin
- DIO = TM1637 Data pin
const uint8_t = Create custom segments referring to This picture
#define ONE_WIRE_BUS 2
#define CLK 4
#define DIO 3
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);
TM1637Display display(CLK, DIO);
int temp;
const uint8_t degree[] = {
SEG_A | SEG_B | SEG_F | SEG_G // °
};
const uint8_t celsius[] = {
SEG_A | SEG_D | SEG_E | SEG_F // C
};
const uint8_t Err[] = {
SEG_A | SEG_D | SEG_E | SEG_F | SEG_G, // E
SEG_E | SEG_G, // r
SEG_E | SEG_G // r
};
const uint8_t CAPt[] = {
SEG_A | SEG_D | SEG_E | SEG_F, // C
SEG_A | SEG_B | SEG_C | SEG_E | SEG_F | SEG_G, // A
SEG_A | SEG_B | SEG_E | SEG_F | SEG_G, // P
SEG_D | SEG_E | SEG_F | SEG_G // t
};- Set brightness of 4-segments display. Can be hex or int, from 8 (min) to 15 (max)
- Clear display
- Open communication with DS18B20
void setup() {
display.setBrightness(10);// 8 - 15 | min - max
display.clear();
sensors.begin();
}- Read sensor
In order
- temperature_from_sensor * 100 21.38 -> 2138
- 2138 / 10 213.8
- round 213.8 -> 214
The purpose is to put in int, one decimal rounded float value (temperature)
- Check if the sensor is wired (unwired sensors output -128 or -1280 after calc) and also if the value is in the capacities of the sensors
-
Display 2 first numbers of int (by dividing it) | false for not showing 0 after when value under 10 | 2 is the number of digits we want to show | 0 is the segment to display
-
Display custom segments degree
-
Display custom segments celsius
-
Like before display 2 first number of int
-
Same
-
Display decimal
- display Err (custom segments)
- "" is for delete old degree symbols without display.clear()
- display CAPt CAPt(capteur) is SENs(sensor) in french...
void loop() {
sensors.requestTemperatures();
temp = round((sensors.getTempCByIndex(0)*100)/10);
if (temp < 1250 && temp > -1270) {
display.showNumberDec(temp / 10, false, 2, 0);
display.setSegments(degree, 1, 2);
display.setSegments(celsius, 1, 3);
delay(2000);
display.showNumberDec(temp / 10, false, 2, 0);
display.setSegments(degree, 1, 2);
display.showNumberDec(temp, false, 1, 3);
delay(2000);
}
else {
display.setSegments(Err, 3, 0);
display.setSegments("", 1, 3);
delay(1000);
display.setSegments(CAPt, 4, 0);
delay(1000);
}
}You can have more than one sensor on the OneWire bus. If it is, juste change number in sensors.getTempCByIndex(X).
The code is completely compatible with any other Arduino-like µcontroller. The only limitation is library compatibilities.