LilyPad Temperature Sensor

SKU: FA1033-5
Sensor Chip

Often MCP9700 (varies by manufacturer/revision)
Output Type

Analog Voltage (proportional to temperature)
Operating Voltage

3.3V – 5V DC
Temperature Range (Typical)

Approx. -40°C to +125°C (Sensor capable range, practical range depends on circuit)
Sensitivity (Typical)

10mV per degree Celsius
Accuracy (Typical)

$\pm$2°C or better
Dimensions

Approx. 13mm (0.5") diameter
Connections

3 Sew Tabs (+, -, S)
LilyPad Temperature Sensor

The LilyPad Temperature Sensor is a sewable, analog temperature sensing board designed for e-textile projects and wearable technology applications. This small, lightweight component integrates seamlessly with any LilyPad microcontroller using conductive thread to provide real-time ambient temperature data.
It is a core component for fashion designers, artists, and engineers who wish to incorporate environmental awareness into their interactive garments, suitable for both educational DIY projects and professional smart textile prototypes.
Description
Incorporate environmental awareness into your wearable technology projects with the LilyPad Temperature Sensor. This board utilizes a simple analog temperature sensor (often a MCP9700 or similar low-power thermistor circuit, depending on the manufacturer) that provides a linear voltage output proportional to the ambient temperature.
The design adheres to the core principles of the LilyPad ecosystem: it is circular, flat-backed, and features large “sew tabs” labeled for power (‘+’), ground (‘−’), and signal (‘𝑆’). These tabs facilitate robust, low-profile connections using conductive thread, turning stitching into functional wiring and making traditional soldering optional.
The sensor operates efficiently within the standard LilyPad voltage range of 3.3V to 5V. As the temperature changes, the analog voltage output from the ‘S’ pin rises (for positive temperature coefficients) or falls, which the Arduino board can easily measure using its analog input pins (returning a value between 0 and 1023). This simple interface makes temperature monitoring straightforward to implement in code.
The sensor’s low power consumption and durable, hand-washable design (with all power sources removed) make it a practical and reliable solution for long-term projects in real-world environments.
Features
  • Ambient Temperature Sensing: Detects surrounding air temperature within a typical human range.
  • Analog Output: Provides a simple, variable analog voltage output that is easy to read with any standard microcontroller analog input pin.
  • Wearable Form Factor: Small, circular design optimized for integration into fabric projects.
  • Sewable Connections: Features large “sew tabs” designed specifically for use with conductive thread.
  • Low Power Consumption: Efficient design suitable for battery-powered wearable applications.
  • Durable: Hand-washable design for practical use in clothing (remove power supply before washing).
  • Clear Labeling: Tabs are clearly labeled with ‘+’, ‘-‘, and ‘S’ for easy wiring.
Usage
The LilyPad Temperature Sensor is used to enable temperature monitoring and reactive behavior in wearable projects:
  1. Smart Clothing: Create a jacket that adjusts integrated heating elements based on ambient temperature readings.
  2. Health Monitoring Prototypes: Develop proof-of-concept wearables that track body temperature variations.
  3. Environmental Data Logging: Build a flexible textile weather station that records temperature data over time.
  4. Interactive Art: Create art pieces that subtly change color or pattern based on the temperature of the room or the proximity of people.
Q: Is this sensor an analog or digital component?

This is an analog sensor. It outputs a continuously varying voltage level based on the temperature, which you must read using an analog input pin on your LilyPad microcontroller.

Q: Do I need to add any external resistors to make this work?

No, the LilyPad board is designed to be plug-and-play within the LilyPad ecosystem. All necessary supporting passive components are integrated directly onto the small PCB, so you connect the three tabs directly to your microcontroller.

Q: How accurate is the temperature reading?

Accuracy is typically very good for ambient sensing applications, usually within $\pm$2 degrees Celsius. For highly precise scientific or medical applications, a different, potentially digital, sensor would be recommended.

Q: Can I use this sensor to measure body temperature?

While it can detect the proximity of body heat, it measures the ambient temperature of its immediate environment. For accurate clinical body temperature measurements, a dedicated medical-grade sensor placed against the skin is required.

Q: Is the sensor washable?

Yes, the sensor board itself is designed to be hand-washable as part of a textile project. The entire project must be hand-washed only, with all batteries removed, and allowed to air dry completely for several days before reapplying power. Machine washing is not recommended.

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