Arduino Uno ds18b20 and sure 2416 dor matrix display

float temperature=0 ; sensors.requestTemperatures();

temperature = (sensors.getTempCByIndex(0));

Serial.println(temperature,DEC); char buffer[4]; itoa(temperature,buffer,10); ht1632_putchar(0 , 0, buffer[0]); ht1632_putchar(6 , 0, buffer[1]); ht1632_putchar(12 , 0, buffer[2]); ht1632_putchar(18 , 0, buffer[3]); ht1632_puttinychar(26 , 0, 'o'); ht1632_putchar(33 , 0, 'C'); delay(150);

do not works... e127 °C show

Which part do you suppose is not working-- the part that reads the temperature from the sensor, or the part that displays the temperature on the LCD screen?

I think that inside buffer there is nothing becouse it write 127. The ds 18b20 works perfectly becouse with lcd skecht show the correct temperature

Some questions :

What do you get on the screen if you just output buffer[0] ?

Does the same problem occur if you output the temperature to somewhere else on the screen ?

What happens if you output the temperature twice ? Output it once then output it again without clearing the screen ?

What does your code do to the screen immediately before showing the temperature ?

What happens if you print some text before the temperature ?

What happens if you put a specific value in the buffer without reading the temperature then output it ?

this is with the code posted

( fot.jpg)

i tryed to give a value and it put on display it and it show the value ( exaple 22.50 )

sensors.requestTemperatures();

float TempC = 22.50 ;//sensors.getTempCByIndex(0);

Serial.println(TempC,DEC); char buffer[4]; itoa(TempC,buffer,10); ht1632_putchar(0 , 8, buffer[0]); ht1632_putchar(6 , 8, buffer[1]); ht1632_putchar(12 , 8, buffer[2]); ht1632_putchar(18 , 8, buffer[3]); ht1632_putchar(24 , 8, buffer[3]); ht1632_puttinychar(32 , 8, 'o'); ht1632_putchar(39 , 8, 'C'); delay(150);

this is the result ( foto22.jpg )

thanks in advance

foto.JPG|640x480

foto22.JPG|640x480

if i write float TempC = 2250; show 22500 °C

in serial monitor show the temperature in this way : 19.4375000000

I think the problem is the decimal

I must divide 19 from 43 without the dot ( or comma )

put 19 into a buffer and the 43 into another buffer

then show it

Right ???

thanks

danielb: if i write float TempC = 2250; show 22500 °C

in serial monitor show the temperature in this way : 19.4375000000

That's strange, I would expect to see: 2250 , wouldn't you?

I think the problem is the decimal I must divide 19 from 43 without the dot ( or comma ) put 19 into a buffer and the 43 into another buffer then show it Right ??? thanks

Pretty much. You will need to adjust your buffer size to 5 and/or adjust your placement on the screen if you want to be able to show "19.43", since that is five characters and your existing code uses four. Or, you could show it as "19.4" and leave it where it is on the screen.

John

yes of course but i can resolve 22500 problem display but not my BIG problem

If I write

float TempC = sensors.getTempCByIndex(0);

I should see something !!! not e127 that is the error when someting goes wrong !!

I need help for this

resolve 22550 end not 22 50 will be able to resolve !!

hi guys don't rell me how but now it WORKS !!!

this is the correct code

sensors.requestTemperatures();

int temp = sensors.getTempCByIndex(0);

Serial.println(temp,DEC); char buffer[4]; itoa(temp,buffer,10); ht1632_putchar(6 , 8, buffer[0]); ht1632_putchar(12 , 8, buffer[1]); // ht1632_putchar(12 , 8, buffer[2]); // ht1632_putchar(18 , 8, buffer[3]); ht1632_puttinychar(19 , 8, 'o'); ht1632_putchar(24 , 8, 'C'); delay(150);

only one question ( easy i think )

now it show the temperature in this format XX °C

and if I would like to show decimal ?

ie XX,X °C ?

how I should change it ?

Many thanks

Daniel

how I should change it ?

Based on snippets? Who knows? Post ALL of your code. Right now, we can only guess what sensors is.

int temp = sensors.getTempCByIndex(0);

Does that method return an int? Or a float?

Pauls Thank you for your answer
the kind of sensor il write on the topic and on the top post… SENSOR IS DALLAS DS18B20

the entire code was just posted so I repost

Thank you so much

Daniele

dallas 18B20.txt (15 KB)

  // returns temperature in degrees C
  float getTempC(uint8_t*);

  // returns temperature in degrees F
  float getTempF(uint8_t*);

  // Get temperature for device index (slow)
  float getTempCByIndex(uint8_t);
  
  // Get temperature for device index (slow)
  float getTempFByIndex(uint8_t);

So, yes all the methods to get the temperature return a float, not an int.

Your buffer will need to be larger, and you'll need to use ftoa(), instead of itoa(). After that, you'll need to put more characters to the display.

thanks
so what i change ?

int temp = sensors.getTempCByIndex(0);

to

float temp = sensors.getTempCByIndex(0); ???

then ?
( I think I must change sometingh here but how ? )

char buffer[4];
itoa(temp,buffer,10);

Many thanks

Daniel

( I think I must change sometingh here but how ? )

Your buffer will need to be larger, and you'll need to use ftoa(), instead of itoa(). After that, you'll need to put more characters to the display.

if i change

itoa(temp,buffer,10);

to

ftoa(temp,buffer,10);

I receive this error

lcd24x16_base_temperatura.cpp: In function 'void loop()': lcd24x16_base_temperatura:112: error: 'ftoa' was not declared in this scope

where is the problem ?

Try dtostrf().

lcd24x16_base_temperatura.cpp: In function 'void loop()': lcd24x16_basetemperatura:112: error: invalid conversion from 'char*' to 'signed char' c:/users/daniele/desktop/varie2/arduino-0023/hardware/tools/avr/lib/gcc/../../avr/include/stdlib.h:581: error: too few arguments to function 'char* dtostrf(double, signed char, unsigned char, char*)' lcd24x16_base__temperatura:112: error: at this point in file

danielb: error: too few arguments to function 'char* dtostrf(double, signed char, unsigned char, char*)'

You aren't passing the correct number and type of arguments to dtostrf(). The documentation tells you what it expects. Only you know what you're actually providing, since we can't see your code, but it's obviously not correct. Change your code so it passes the arguments that the function expects.

I understand the kind of error but I don't know what I should write.

sensors.requestTemperatures();

float temp = sensors.getTempCByIndex(0);

Serial.println(temp,DEC); char buffer[8]; dtostrf(temp,buffer,10); <====== Float temp inside to buffer in decimal type but how change it ? ht1632_putchar(6 , 8, buffer[0]); ht1632_putchar(12 , 8, buffer[1]); // ht1632_putchar(12 , 8, buffer[2]); // ht1632_putchar(18 , 8, buffer[3]); ht1632_puttinychar(19 , 8, 'o'); ht1632_putchar(24 , 8, 'C'); delay(150);

temp is the variable where the sensor give the reading of temperature buffer is where temp goes

how convert by dtostrf float temp to buffer ?

the error is

dtostrf(double, signed char, unsigned char, char*)

what is double ? what is signed char ? what is unsigned char ? what is char* ?

many thanks

Daniel

http://lmgtfy.com/?q=dtostrf&l=1

This has information about what the parameters need to be. If you have trouble interpreting it, post back with what you tried and why :)

Cheers, John