Color Changing Warming Hat Using Arduino

Problem with my circuit

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Step 1: Please Help

Im actually writing this to try to get some feedback from some people.

For one of my final projects in school I am making a beanie with color changing fabrics that should heat up and change colors when the temperature outside gets below a certain temperature.

We are getting so far into our project and when it finally becomes time to test it out its failing.

We have rebuilt the circuit twice and we know the code is fine because we have gotten it to work with an LED.

I will post below everything I have done before and hopefully I can get some good feedback.


Step 2: Temperature Sensor

First I set up my temperature sensor in a breadboard and checked to make sure it was working and it was. It was reading temperature perfectly and when head was added the temperature was changing. We also on the breadboard had it so an LED was turning on when the temperature got below a certain point and that was working perfectly too.

Step 3: Changing the LED to the Heading Pad

Now comes the fun part,

We at first tried one transistor that was getting way too hot for how much power was giving off from the circuit so I ended up going with the TIP120. What seems to be happening with my circuit is which ever signal pin is being used is failing which is not allowing power back to my heading pad. We recreated the circuit twice and the same thing happened both time. I did many hours of research to see if this was a common problem but I couldn't ever find a direct answer. We have checked every connection and they are all receiving power so we are having a hard time figuring out what is going on with our signal pin.

If anyone could help that would be awesome.

Thank you!

Step 4:



    • Indoor Lighting Contest

      Indoor Lighting Contest
    • Make It Fly Challenge

      Make It Fly Challenge
    • Growing Beyond Earth Maker Contest

      Growing Beyond Earth Maker Contest



    1 year ago


    This should never have been posted as an instructable, as it's not - The forums would be the correct place for such, but anyway...

    For anyone to help you, you must provide the relevant info, such as the schematic of the parts you cannot get to work (with values) and the specs of the heating pad - Voltage and either max. current or its resistance.

    Depending on the heating pad parameters, the TIP120 will be a poor to downright useless choice, as its collector-emitter voltage drop can easily be up to ~4V with a large collector current. A much better choise would be a Logic Level MOSFET (a Fairchild FDP8860 30V, 80A 2.5mOhm would do really well, but there's a host of other possible options as well)

    From what you write, it sounds like you load the outputs really hard (if I read you right), but provide schematic and heating pad data and it's a one-minute-fix :)

    Have a nice day :)