Fun with Cheap Chinese Thermometers

Fun with Cheap Chinese Thermometers
Introduction

A dilemma came up when we were trying to get a friend's wine fridge set just perfectly - we needed a way to quickly measure the temp inside. So how do I solve any problem? To eBay!

The answer was a set of cheap Chinese-made thermometer panel meters, shipped from China for only $2.24 a piece. Might as well order 15, they're cheap... Silly me, though. I had guesses that these delightfully cheap little meters would come with a selector switch for Celsius or Fahrenheit, but obviously for $2.24 total (part + shipping halfway around the world), what do you expect?

Anyway, being Americans, we don't much care for Celsius. It's right up there with meters on the list of highly rational things we ridicule with great disdain. Since I did have 13 extras (I actually needed one for my wine storage, one for Lisa's...), I figured opening up one wouldn't hurt. After all, who would design an incredibly intricate, integrated temp measurement part and not make the provision for switching it between scales? My only hope was that the board designers had been just as gracious and pinned out what I needed.

Fear not, for I found the answer...

The part itself is just a die on the board, covered with a drop of epoxy. In my remaining 13, I found two distinct styles, but both had the C/F switch pin brought out to a set of solder pads.

(Pictures coming shortly to illustrate the process...)

  Questions? Email Nathan Holmes
© NDHolmes, but freely usable under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 License.
Last modified on December 29, 2009, at 08:54 PM
Edit Page | Page History