I have been experimenting the last couple days with a wearable electronics project – a wireless body temperature monitor/logger. The idea is to remotely monitor kids body temperature, if they are sick, and put up a status display with alarm function in our bedroom. The remote monitor will be another Funky with RGB LED for visual temperature representation and a OLED display with a piezzo buzzer to sound alarm, if the temperature goes above a threshold. Since the transmissions are picked up by my IoT gateway and logged to emoncms, I can visualize that data remotely, including on my phone. Body temperature data is collected and transmitted wirelessly by a Funky v2 equipped with a DS18B20 temperature sensor and a CR2032 battery holder (extra flat one). I soldered a 0603 sized 4.7K resistor on the DS18B20 (required for its operation), pictured below (really miniature):The wires were then covered with heat shrink tube:
The node is running the DS18B20 sketch; I wanted to stress-test it and am sending data every 5 seconds. The final project will send once a minute.
Obviously the position of the sensor isn’t optimal, I would get all sweaty when mowing outside in the intense heat (resulting in dropped temperature readings); I even took a shower with the sensor covered with a dry towel. Measuring temperature under the arm requires it to be firmly pressed to the sensor, while I have my hands moving around all the time, resulting in falsely low readings. Maybe I need to try another location for attaching the sensor. Below is an infrared image of a human body (taken from here)
Overall interesting project with potential for use.