unstable Project with Arduino Nano

Hey Everyone,

description

i (tried) to build a Project to control my destillery (especially the heat source).

It should show the actual temperature comming from a DS18B20 and show it in the Display.
i use two buttons to rise and lower the maximum temperature (to wich i try to heat the destillery)

the code controls a relay, which sould simply turn on and off the heat source to rise the temp and go off on maximum temperature.

the second Temperature (pt100)is for a emergency shutdown to measure the water in the cooler. if it goes to high it turns off the heater, and make some noise (relay two).

No to the actual problem(s):

issues

  1. the sensorvalue i get from the pt100 is not stable(converted in degrees C it goes up and down for like 2-3), and i cant tell why. i can live with that for the emergancy shutdown, but not for the exact temp on the distillery itself. anyway it should not be this way… ::slight_smile:

  2. all the rest worked fine for like 2h, than turned into a gremlin… :fearful: which leads me to

  3. every then and now, i get 85 degrees from the ds18b20, which means (so far i read) it is not connected well, what simply cant be… its rock solid and i can mesure the whole way throug with my multimeter without any issue. sometimes no issue for like 1h or more sometimes all the time. sometimes it flaps to 85 and back to normal. :sob:

the code itself (so far i testet the 2h in line) works, what makes me think the gremlin is somewhere in my elektronics/ the way i wired it up.

i tried to sketch it in fritzing as good as i could (pic below).

Can anybody tell me what i did wrong, to tame this monster back to normal?!?! :confused:

  • Could you please post a normal schematic instead of that hard to understand diagrams? Fritzing has this option.
  • What is you heater wattage?
  • For PT-100 I'd recommend to use MAX31865 amplifier module.

alesam: - Could you please post a normal schematic instead of that hard to understand diagrams? Fritzing has this option.

i can try, i opened the scematics view, but it looks quite weird, i dont think its correct. Is it drawn automatically, or should i connect the parts in this view as well?

alesam: - What is you heater wattage?

500W, but the issues occur also if the heater is not connected (because i can see the LED of the Relay/hear the relay clicking)

alesam: - For PT-100 I'd recommend to use MAX31865 amplifier module.

But the Transmitter has an higher resolution due to the higher range (usually... sadly somehow not in my case it seems) Or is this not the case?

Sorry but there is nothing to discuss till you post a readable schematic.

i opened the scematics view, but it looks quite weird, i dont think its correct. Is it drawn automatically, or should i connect the parts in this view as well?

When you add components to the breadboard view, they are also automatically added to the schematic view, but in “random” positions. It is for you to arrange them into an easy to read and understand diagram.

When you connect components in breadboard view, they are also automatically connected in schematic view, but with straight thin lines. These thin lines are only to guide you. It is for you to draw the connections in an easy to read and understand way. The thin lines are only there to help you remember what is connected to what in breadboard view, so you don’t connect the wrong components by mistake, or miss any connections.

This technique works the other way around as well. If you had started off by drawing your schematic on a blank screen, and then switched to breadboard view, all the components would be there in random positions with thin lines connecting them. You could then draw the wires or plug the components into a breadboard and Fritzing would help you by indicating if you had got the connections right or wrong, based on what you drew in the schematic.

Starting by drawing the schematic, then moving on to the breadboard layout, is a much more sensible approach, leading to fewer errors.

A schematic should be easier for you to draw and for others to read and understand, compared to breadboard view. In a schematic, you don’t have to represent the complexities of the physical aspects of the circuit, such as the location and size of components. Lay them out however you like so that connections are neat and don’t cross over each other (as far as you can).

A great tip for drawing a schematic is to use “power” symbols for 5V, 24V and GND. Put as many of these in as you like, near to each component that need them. Then you don’t have to draw in all the lines between them, which makes the schematic neater and easy to read. They are assumed to be connected.

For example, if you had started with the schematic view and drawn the breadboard view after, you would probably have avoided the mistakes you can see here:


You have multiple wires & pins going into the same breadboard holes, which you can’t do physically. Also, the 4K7 is shorted by the breadboard track.