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Project: Temp Sensing Coffee / Tea Sleeve

30 November 2009 6 Comments

Last weekend I came down with a bad cold, so no circuit projects for me. However drinking a ton of tea gave me some inspiration for this week’s experiment – a coffee cup sleeve that warns you when your drink is too hot. I don’t know how many times I have been burned by super-hot green tea, so here is my fun little solution to that problem.

I’ve been wanting to play around with sensors, and while surfing the net one day I came across Aniomagic’s Learning Sensors. They are nice little sewable sensors that come in a few different varieties. The temperature one caught my eye because it is self-contained and you don’t need to hook up any external microcontrollers to play around with it.

Aniomagic's Temperature Sensor (image via Aniomagic.com)

Aniomagic even has a cool tutorial for a temperature sensing coaster, which I ended up adapting for my coffee sleeve idea.

Aniomagic's Smart Coaster Project (image via Aniomagic.com)

For my project I used my favorite little bipolar LEDs from Electronic Goldmine as the eyes for a fleece Penguin. The temperature sensor is hidden behind his belly and lights the LEDs red if the temperature is higher than my calibrated preference, and green when it is ‘just right’. Once the temperature drops lower than my preference, the LEDs turn off. There is a 3rd output that I could have hooked additional LEDs to, but I liked the simple red/green communication as I am more concerned with the higher temps than my beverage being too cold.

My Temperature Sensing Coffee/Tea Sleeve

This was a fun little project to wire up and I’m happy with the design. After testing it I found that the sensor needed to be pressed right up against the cup or it lost the reading, this can be solved by placing your fingers right on the penguin to keep the tension. I tried it out on some green tea, and I think I’ll bring it along on my next visit to my local coffee shop and see how it does with different beverages.

Check out some progress shots and details of construction at my Flickr account.


  • Kristen said:

    Holy crap. This is SO awesome. Talent, you haz lotz!

  • Kaylee said:

    Ahh! Angela, I love it. It’s so damn cute. Your creativity never ceases to astound me.

  • Karen Fraga said:

    First, let me just say the coffee sleeve is so cute! I had this idea that if you cut out a heart shape instead of the penquin it would be perfect for Valentine’s day! Anyway, I also wanted to comment on the TEI show that you went to recently (as seen on Fashioning Technology Blog). It seemed amazing! I wish that I could learn some of the things that you saw. Actually, I wish that I had some of the knowledge so that I could teach some classes. The economy is so tough right now. I have been looking for a job but haven’t been able to find one (I have been looking for a clerical position). I have often thought that I think outside the box – there has to be a way to make some money. I bought Syuzi’s book but money is tight right now to buy some of the items in it to try it out. Bummer! If you have any ideas for making money, please let me know. Thank you so much, I really appreciate it.

  • softcircuitsaturdays (author) said:

    Hi Karen, I’m not sure about making money from soft circuit projects – you can always try selling some of your successful experiments on Etsy. But playing just to learn is definitely a worthwhile endeavor. If you look around on Instructables and on some of the sites from Craft and Makezine there are lots of free tutorials about this stuff out there.

    Have you seen the new kit at MakerShed (http://www.makershed.com/ProductDetails.asp?ProductCode=MSCBP), it provides a few of the conductive materials used in Fashioning Technology that would otherwise be pretty pricey to buy separately.

  • calebhc said:

    I’ve heard a lot about e-textiles but never got involved and built anything yet until I saw this little project! I’m definitely going to try building this and start experimenting with this whole new world of electronics. Thanks for sharing this awesome project! :)

  • Ardent Smith said:

    This looks amazing.

    I think you could have kept blue color LED for the 3rd part that shows the coffee/tea is too cold!!

    Ardent Smith
    Visit us at: Create Video Games

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