A Chameleon That Tells You the Temperature

by chickensoup94 in Circuits > Wearables

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A Chameleon That Tells You the Temperature

Abha&Nikhil_Weatherwiz_3.png
A Chameleon that tells you what the temperature is

In this project, we will create a small fabric patch shaped like a chameleon. It will light up and change colors based on the surrounding temperature. We will use the Circuit Playground Classic board from Adafruit and a 850 mAh battery​.

You can style this patch on any outfit, pin it to your shirt, jacket, or scarf, and let it serve as a gentle reminder of when to bundle up!

Supplies

supplies.png
  1. Adafruit Circuit Playground Classic​
  2. Sewing kit
  3. White felt fabric ( For the base of the chameleon )​
  4. Translucent / transparent beads
  5. Cotton pads ( diffuser )
  6. 850mAh battery​
  7. 2 pairs snap button

Make the Chameleon

process.png




  1. Draw a rough Chameleon outline on a piece of paper. Place this paper on top of the felt fabric and trace around its edges. Make sure the outline is large enough to fit the Circuit Playground Classic and the battery inside. Keep in mind that beading and stitching around the edges will slightly reduce its final size, so give yourself a bit of extra room when drawing and cutting.
  2. Carefully cut the felt along the traced outline to create the front patch.
  3. Start sewing beads around the eye area first, then continue filling in the rest of the body with beads. Get creative. Make sure the beads that you select are translucent or transparent enough for the light to pass through.
  4. Cut another plain felt piece the same shape as your first patch.
  5. Attach the two felt pieces together around the edges. Make sure to leave an opening or sew it in a way that still allows you to insert the circuit board, battery, and cotton. Once done, you’ll have a little pocket that holds everything in place.
  6. Additionally, you can stitch a zipper along the pocket opening to keep your circuit and battery secure, ensuring it lines up well so you can easily open and close it as needed.
  7. Finally, add snap fasteners to the back of the patch. This will let you easily attach and remove your chameleon from clothing, bags, or any fabric surface without permanently sewing it on.

Upload the Code to Circuit Playground

(Note: The Circuit Playground Classic already has a built-in temperature sensor and NeoPixels, so no extra sensors or LEDs are needed.)

Use a USB cable to connect the Circuit Playground to your computer and upload the following code on the Arduino IDE application installed on your computer.

Code

Note: Make sure to change the temperature range to your liking. The code below has '31' set as the minimum (blue) and '32' set as the maximum (red), with a smooth color transition for values in between.

#include <Adafruit_NeoPixel.h>
#include <Adafruit_CircuitPlayground.h>

#define NEOPIXEL_PIN 17
#define NUM_PIXELS 10

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_PIXELS, NEOPIXEL_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
strip.begin();
strip.show();
strip.setBrightness(50); // LED brightness
Serial.begin(9600);
}

void loop() {
float temperatureC = CircuitPlayground.temperature();

if (temperatureC < 31) { // minimum temperature value
for (int i = 0; i < NUM_PIXELS; i++) {// accessing all pixels
strip.setPixelColor(i, 0, 0, 255); // Blue color for temperature < 31°C
}
} else if (temperatureC >= 31 && temperatureC <= 36) {// minimum and maximum temperature values

uint8_t red = map(temperatureC, 31, 36, 0, 255); // mapping to temperature
uint8_t blue = map(temperatureC, 31, 36, 255, 0);

int fade = 100 ;


for (int i = 0; i < NUM_PIXELS; i++) { // logic for gradual smooth transition
strip.setPixelColor(i, 0 + (temperatureC * fade), 0, 255 - ( temperatureC * fade));
}
strip.show();

}
else {
for (int i = 0; i < NUM_PIXELS; i++) {
strip.setPixelColor(i, 255, 0, 0); // Red color for temperature >= 36°C
}
}

strip.show(); // Show the updated color

Serial.print("Temperature Celsius: ");
Serial.print(temperatureC); // Print the temperature value
Serial.println(" °C");
// Serial.println( blue );

Serial.println();
}

Additional code to try: https://github.com/Thomasieee/Wearable-Electronics/blob/main/Weather-Wiz


Test the Circuit

Screenshot 2025-03-02 at 1.08.08 PM.png
  1. Plug the 850mAh battery into the Circuit Playground’s JST battery connector.
  2. Adjust the temperature threshold if needed.
  3. If you want an on/off switch, you can add one between the battery and board, or simply unplug the battery when you’re not using it.


Assembly & Enjoy

Asset 1.png
  1. Once you confirm the circuit is working, gently slide the Circuit Playground (with the battery) into the pocket you made between the two layers of felt. Add cotton pads in front of the Circuit Playground to diffuse the neo pixels (if needed).
  2. Test your chameleon in various temperatures and weather conditions to see the color change. Keep in mind that the color transitions happen gradually, so allow a moment for the chameleon to shift from one color to the next.