Please help with code for DS18B20

[astanapane]

i'm facing the same problem with the LED output pulses.

Is there anyone has the same problem? I cannot fix it.

Once the temp goes closer to the SET temp, the output seems to have pulses before it light the LED at its level.

It looks like the PIC sends pulses at the very close set temp and once it comes to the action, lights the LED.

To be more specific.

Lets say we SET the TEMP at 22 C. and .10 C. the plus and minus from 22 C.

If the display goes to 21.6 or 21.8 the indicator LED flashes very low with pulses.

If the TEMP goes to 22.20 then the LED lights.

Please let me know if anyone of you having the same problem. To program i use the PIC KIT 2.

thanks a lot.

I would like to say that i have test the circuit with Transistor also and Resistor 4,7K.

But at the point close to the set TEMP the led keeps flashing, and once is reaching the (emaple 22.20 C) it goes stable active.

[Ioannis]

The comparisson is done with the program code in post #88?

Ioannis

[astanapane]

Hi Ioannis,

Yes, i have added the lines Fratello told me in order to activate the outputs.

[Ioannis]

It should not do this. The code has some kind of hysteresis which prevents the play at he output.

What if you increase this hysteresis?

Ioannis

[fratello]

I made tens of this thermostat, for all my friends, relatives....without troubles. Maybe it's time to show us Your schematic !

[Acetronics2]

May we ALSO see your FULL code ???

...

Alain

[astanapane]

Yes sure, i will upload the code soon, and i will also make a small video if you want.

On the output, i have done the following configurations.

1) only an LED
2) light the LED through resistor.
3) light the LED through a transistor.

In case number 1. the 3MM LED does not go ON but it flashes very low with some pulses, it is not noticeable. (the 5 mm goes on)
In case number 2. the LED works just fine
In case number 3. the LED works just fine

My question is, if anyone understands why it does not light up straight from the PIC (pin) output with no transistor or resistor.

thanks a lot and sorry for the trouble