Temperature Module New Battery and Case

Last crawled date: 1 year, 11 months ago

I have a simple internal and remote temperature station with an LCD display (by Ascot). My remote temperature sensor is battery powered with 2 x AAA batteries. I find these batteries don't last long (<6 weeks) and become ineffective once the battery level drops to about 1.4V per cell, especcially in the colder months.

My battery solution is to replace the AAA batteries with a single 18650 LiPo battery. The battery is rechargeable and should last for many month of use. Of course the new thermometer and LiPo battery needs a new enclosure to protect it from the elements, so this custom 3D printed case was designed.

The temperature module has a measured quiescent current 650uA, with regular power spikes during temperature signal transmission. To note, a fully charged LiPo battery will have a voltage in excess of 4V. To avoid the excessive high voltage across the thermometer, I have included a diode in series with the LiPo to drop the voltage by 0.6V.

Possible Design Improvements:
1. Include a LiPo charging circuit with external DC charging connector.
2. Improve case to provide flex support for front panel.
3. Re-position case side airflow vent to accurately align with thermometer module.

My print is made in PETG 1.75mm Aurarum silver filament, with 0.2mm layer height and 25% infill on a PRUSA I3 MK3S printer.

I hope you can find this print useful, too.