Actions
Forum Thread Details
  • Replies 17 replies
  • Subscribers 394 subscribers
  • Views 983 views
  • Users 0 members are here
Related

Temperature controlled relay (help needed for noobie)

Former Member

Hello, my name is Aisha this is my first post and I am excited to get into the community.


I live in a studio apartment with my wife. The entire apartment is on a 15amp breaker so we have to be careful about power use. We find if we run the A/C and cook something in the kitchen the fridge will kick on more often and trip our breaker. We have a blower to pull hot air out of the kitchen and I would like to use an arduino to turn it off and on based on the temperature.


I have:

 

an arduino uno

a tmp36 temperature sensor

a 5v arduino relay module

a breadboard and leads

 

I want to do this not only the right way and the best way with what I have available. I have used the arduino to switch the relay using the blinking LED code from a kit I got. I have wired up the sensor and read readings off of it.

 

 

The tutorials I find online say I should connect it to 3.3v and also AREF to 3.3v when I do this I don't get 3.3v in my serial monitor like the tutorials say but 1.5 (average). I am left lost as no tutorials show how to do this without an LCD screen and with a relay module. I don't need to monitor the temperature after I have it set properly once so an LCD is unnecessary (though I would not mind being able to add on in the future.)

 

I plan to put the sensor on a cable, are there limits to how long a cable can be for this sensor? I was planning on using cat5 cable.

 

So far all of my experiments with arduino involve copy pasting code and maybe modifying a couple lines that are clearly labeled or that a tutorial has told me to edit. I have 0% skills and about as much understanding and confidence in coding anything let alone a micro controller.

 

I have seen people adding things like data logging to increase accuracy of readings and delays to keep the switch from tripping like crazy but again I'm still struggling with the hardware and code is not at my level yet.

 

Hopefully there are people who can help me out. I know this is super easy for anyone who knows how to use and code arduino, I just need some help getting my first project finished.

Parents Reply
  • in reply to mcb1

    I am unsure what is dangerous about using the hot glue. I soldered everything. The glue is mostly to physically keep the power connector in the box.

     

    My fan doesn't draw that much power so I don't see heat becoming an issue with the electrical connections.

     

    I don't want to sound argumentative but I simply don't understand the issue with this project and the hot glue.

     

    I would be worried about the box and and  insulation on the wires if it was likely to get that hot.

Children
  • in reply to Former Member

    I am unsure what is dangerous

    That is why we try to provide education about the dangers.

     

    Relying on hot glue to stop the cable from being pulled and exposing the wires is one issue.

    The cardboard box is not a suitable insulator if it becomes damp, and will in fact conduct, and since it is not earthed, then it potentially become live.

    The fact that the cardboard box privides no ability to earth and has no strength is another.

     

    While you might be careful and treat it with care, what about a small child, or someone tripping on the wire.

    How would you feel if the item you created was the cause of injury to someone else?

     

     

    If you type Unsafe Mains into the site search, you will find numerous posts where we have raised similar issues.

    image

     

    So please don't feel I am targetting you personally,  .... just the practice.

     

    If you want advise on how to minimise these risks, then we are more than happy to assist, but you should open it a as new discussion.

     

     

    Mark

  • in reply to mcb1

    I am absolutely with Mark on this one. While you get top marks with project progression, it would be a Zero for the enclosure and safety.

     

    The glue may hold the cable but the cardboard will not hold the glue or any of the other parts in the "Shoe Box" style enclosure. one drop and everything will go flying

     

    You can get some very good and reasonable priced enclosure from most local hardware store (Look at my Safety Box as an example Safety Outlet for the Home Bench or Lab). Actually this video was all about safe practices in the lab.

     

    And you have stated this project is going into a kitchen, this is a place prone to moisture or worse so the requirements are way higher

     

    Please fix the enclosure, board mounting and strain relief, then we should be much happier image

     

    Oh and as Mark stated, this is not personal, we will comment on any project showing bad (Unsafe) Practices. This is a family show after all.