Hello
I'm working on a project, and I need 4 DS18B20 digital sensors and some solar cells to read temperature changes and amount of sunlight. I don't believe hardware is a problem. And the solar cells are working fine, I had this problem before and after I added the cells. I'm using this code:
#include <OneWire.h>
#include <DallasTemperature.h>
// Data wire is plugged into port 2 on the Arduino
#define ONE_WIRE_BUS 2
#define TEMPERATURE_PRECISION 9
// Setup a oneWire instance to communicate with any OneWire devices (not just Maxim/Dallas temperature ICs)
OneWire oneWire(ONE_WIRE_BUS);
// Pass our oneWire reference to Dallas Temperature.
DallasTemperature sensors(&oneWire);
// arrays to hold device addresses
DeviceAddress insideThermometer, outsideThermometer, insideThermometer2, outsideThermometer2;
void setup(void)
{
// start serial port
Serial.begin(9600);
Serial.println("Dallas Temperature IC Control Library Demo");
// Start up the library
sensors.begin();
// locate devices on the bus
Serial.print("Locating devices...");
Serial.print("Found ");
Serial.print(sensors.getDeviceCount(), DEC);
Serial.println(" devices.");
// report parasite power requirements
Serial.print("Parasite power is: ");
if (sensors.isParasitePowerMode()) Serial.println("ON");
else Serial.println("OFF");
// assign address manually. the addresses below will beed to be changed
// to valid device addresses on your bus. device address can be retrieved
// by using either oneWire.search(deviceAddress) or individually via
// sensors.getAddress(deviceAddress, index)
//insideThermometer = { 0x28, 0x1D, 0x39, 0x31, 0x2, 0x0, 0x0, 0xF0 };
//outsideThermometer = { 0x28, 0x3F, 0x1C, 0x31, 0x2, 0x0, 0x0, 0x2 };
// search for devices on the bus and assign based on an index. ideally,
// you would do this to initially discover addresses on the bus and then
// use those addresses and manually assign them (see above) once you know
// the devices on your bus (and assuming they don't change).
//
// method 1: by index
if (!sensors.getAddress(insideThermometer, 0)) Serial.println("Unable to find address for Device 0");
if (!sensors.getAddress(outsideThermometer, 1)) Serial.println("Unable to find address for Device 1");
if (!sensors.getAddress(insideThermometer2, 2)) Serial.println("Unable to find address for Device 2");
if (!sensors.getAddress(outsideThermometer2, 3)) Serial.println("Unable to find address for Device 3");
// method 2: search()
// search() looks for the next device. Returns 1 if a new address has been
// returned. A zero might mean that the bus is shorted, there are no devices,
// or you have already retrieved all of them. It might be a good idea to
// check the CRC to make sure you didn't get garbage. The order is
// deterministic. You will always get the same devices in the same order
//
// Must be called before search()
//oneWire.reset_search();
// assigns the first address found to insideThermometer
//if (!oneWire.search(insideThermometer)) Serial.println("Unable to find address for insideThermometer");
// assigns the seconds address found to outsideThermometer
//if (!oneWire.search(outsideThermometer)) Serial.println("Unable to find address for outsideThermometer");
// show the addresses we found on the bus
Serial.print("Device 0 Address: ");
printAddress(insideThermometer);
Serial.println();
Serial.print("Device 1 Address: ");
printAddress(outsideThermometer);
Serial.println();
Serial.print("Device 2 Address: ");
printAddress(insideThermometer2);
Serial.println();
Serial.print("Device 3 Address: ");
printAddress(outsideThermometer2);
Serial.println();
// set the resolution to 9 bit
sensors.setResolution(insideThermometer, TEMPERATURE_PRECISION);
sensors.setResolution(outsideThermometer, TEMPERATURE_PRECISION);
sensors.setResolution(insideThermometer2, TEMPERATURE_PRECISION);
sensors.setResolution(outsideThermometer2, TEMPERATURE_PRECISION);
Serial.print("Device 0 Resolution: ");
Serial.print(sensors.getResolution(insideThermometer), DEC);
Serial.println();
Serial.print("Device 1 Resolution: ");
Serial.print(sensors.getResolution(outsideThermometer), DEC);
Serial.println();
Serial.print("Device 2 Resolution: ");
Serial.print(sensors.getResolution(insideThermometer2), DEC);
Serial.println();
Serial.print("Device 3 Resolution: ");
Serial.print(sensors.getResolution(outsideThermometer2), DEC);
Serial.println();
}
// function to print a device address
void printAddress(DeviceAddress deviceAddress)
{
for (uint8_t i = 0; i < 8; i++)
{
// zero pad the address if necessary
if (deviceAddress[i] < 16) Serial.print("0");
Serial.print(deviceAddress[i], HEX);
}
}
// function to print the temperature for a device
void printTemperature(DeviceAddress deviceAddress)
{
float tempC = sensors.getTempC(deviceAddress);
Serial.print("Temp C: ");
Serial.print(tempC);
Serial.print(" Temp F: ");
Serial.print(DallasTemperature::toFahrenheit(tempC));
}
// function to print a device's resolution
void printResolution(DeviceAddress deviceAddress)
{
Serial.print("Resolution: ");
Serial.print(sensors.getResolution(deviceAddress));
Serial.println();
}
// main function to print information about a device
void printData(DeviceAddress deviceAddress)
{
Serial.print("Device Address: ");
printAddress(deviceAddress);
Serial.print(" ");
printTemperature(deviceAddress);
Serial.println();
}
void loop(void)
{
// call sensors.requestTemperatures() to issue a global temperature
// request to all devices on the bus
delay(1000);
Serial.print("Requesting temperatures...");
sensors.requestTemperatures();
Serial.println("DONE");
// read the input on analog pin 0:
int sensorValue = analogRead(A0);
// Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
float voltage = sensorValue * (5.0 / 1023.0);
// print out the value you read:
Serial.println(voltage);
delay(1000);
// print the device information
printData(insideThermometer);
printData(outsideThermometer);
printData(insideThermometer2);
printData(outsideThermometer2);
}
When I upload it to the arduino uno and open the serial monitor. It reads data for each sensor normally giving the temperature in C for every 0.5C (for example 24.00 C, 24.50 C, 25.00 C, 25.50 C etc) However after a while, it randomly says the temp are at 85 C for a split second!! (sometimes -127). After that, the temp comes back to normal, but it gives it out for every 0.001 C!? (example: 24.02 C, 24.67 C, 25.14 C etc). And every once in a while it goes to 85 C for a second,then back to normal. Also each sensor usually does this, sometimes all at once. The picture I attached is an example. In the third row the temperature for the 2 middle sensors jumps at 85.Ignore the 1.72, that's the amount of light in my room.
This never happened with just 2 temp sensors. Thanks!!
