Public Lab Research note

Temperature Sensor / LED light

by sobers | November 28, 2011 23:36 28 Nov 23:36 | #594 | #594

Materials: 1. Cheap Digital Thermometer 2. Arduino 3. RGB LED 4. Resistor (for RGB LED to not burn out) 5. 9v Battery (or another power source for the arduino)

Digital Thermometer Parts

Taking a digital thermometer from a convenience store (CVS), we extracted the metal and two wires used to read your temperature when sick.

To do this we used a dremel (or any other small drill) to carefully take apart the tip of the thermometer from the body. Be careful as the wires are very thin and small.

(All images are available to download / or see at full size at the bottom of this page.)

Thermometer Part + Additional Wiring Next we took the thermometer part and soldered each end to a thicker hookup wire. We taped down the thermometer and thin wire to a piece of cardboard to give it more structure (so that the wires would not fall apart on us). Using any sturdy material will do for this.

Sensor & Breadboard hookup 1

Sensor & Breadboard hookup 2

Here are general images of the wiring we did, hooking it up to an Arduino UNO. See the code (below & in the attachment "") for which pin = which connection.

Sensor & Breadboard hookup 3

The arduino code is from a few different sources (see below for our compilation): Reading the thermistor, simple code:


Arduino RGB LED HSV "Color Wheel"

Files Size Uploaded 1.36 KB 2011-11-28 23:38:20 +0000
DSC05649.JPG 1.41 MB 2011-12-05 22:19:13 +0000
DSC05660.JPG 1.44 MB 2011-12-05 22:20:14 +0000
DSC05662.JPG 1.31 MB 2011-12-05 22:21:19 +0000
DSC05663.JPG 1.25 MB 2011-12-05 22:28:56 +0000
DSC05665.JPG 1.38 MB 2011-12-05 22:36:11 +0000


In my experience, it's a bad idea to attach extra wires to a working thermocouple. The very small extra resistance from the wires can affect the temperature reading. But if you're recalibrating after the fact, maybe that's not a big deal :)

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