Monitoring a child's body temperature using Puck.js?

Hi all

somebody recommended the Puck.js to monitor the temperature of our 3-year old grandchild.

Some months ago she suffered from febrile seizures caused by a sudden rise in body temperature (due to a virus, perhaps in combination with a bacterial infection).

Since then her parents are always cautious whenever her temperature rises, which is mostly at night.

Would the Puck.js be the best solution to monitor this? If so, any suggestions about how to establish the contact with her body? We're thinking about a bracelet or sewing it into a night gown, ...

Any feedback is welcome!

Thanks in advance for your help.

Paul.

Wow, that's a great use.

With the Pucks, there is a 'watch case' by @MaBe that can be 3D printed: https://www.thingiverse.com/thing:2095572

That could either go around her wrist, or you could sew it on. I do sell spare plastic cases so you could also just drill some holes in a normal one and sew through if needed though.

Actually measuring the temperature could be a bit prone to error. While the Puck can measure temperature pretty well once you calibrate the offset (eg, take a temperature reading with it at a known temperature) the sensor is on the chip so won't directly be in contact with your grandchild's skin and would I imagine take a while to respond to any temperature changes.

You could add something like a DS18B20 though - the TO-92 versions are the size of a small transistor, respond quite quickly, and are calibrated and pretty accurate. You could just wire one onto the Puck and cut a small hole in the case so it was extremely close to your granddaughter's skin.

The only gotcha is the DS18B20 draws around 1mA when on, so would flatten the battery in ~7 days. You'd just need to power it from an IO pin so you can turn it off between readings.

Thanks for your feedback, Gordon!

The watch case looks nice, so we may give that a try. If so, we'll let you know if we need a spare plastic case.

The DS18B20 TO-92 temperature sensor looks promising.

Turning it off between readings will indeed extend the battery life. The monitoring should only be necessary for some days in a row (and perhaps even only during the night time), so the battery should not be a problem.

We'll discuss the possibilities and let you know the outcome.

Thanks again for your help!

Hi Gordon - So is the calibration process just as simple as determining the difference that should be added to the puck temperature reading, and adding that every time you take a temperature, or is it a more complicated? (just FYI the temperature readings I get with my puck are differing from an Elitech logger by about -4 C).
Many thanks, Roland

Regarding the temperature sensor I'd suggest to take a BME280. It measures temperature and humidity at "1.8 µA @ 1 Hz" according to the data sheet, and it is fully calibrated.
There are breakout boards available with the chip on top (all other parts on the bottom).

Yes, BME280 seems good - DS18B20 is the classic digital temperature sensor but they're actually surprisingly pricey.

@RolandGalibert yes, that's correct. I believe the actual change the value based on temperature is really pretty reliable, it's just that the 'base' value changes from chip to chip and isn't calibrated at the factory - so just adding/subtracting a single value should sort things out for you.