In Part 1 I disassembled the weather station outdoor unit to inspect and eventually replace (with the wrong part) the temperature and humidity sensor.
Trying to see why there was no result on the weather display I took a picture using my phone and carefully aligned the chip with the light to be able to photograph the part number. The part number of the original and the part number of my first replacement sensor were not compatible.
Now armed with the actual chip number used by the weather station I found that it was this one: https://www.sensirion.com/products/catalog/SHTC3/
In doing searches to buy that chip I found lots of hits, but in a surprising number of forms. The one I ended up getting had a plastic guard cage around it and it was soldered to a board with a header. The packaging even included jumpers for experimenting with an Arduino or Pi. I ended up ordering https://www.amazon.com/dp/B0CKVMDJW5 since it would arrive in a couple of days. With shipping most of the options on Amazon or eBay ended being in the $10 range.
As an aside, don’t overlook your smartphone as a reading aid for small markings. I actually have a “USB Microscope” that give about a 600x magnification. I actually get a better picture out of my smartphone (a Samsung S21) using the telephoto lens (3x on the screen) which actually allows me to focus closely. This ability is called macro if you look for it in documentation.
The new board came with right angle header pins on it. Unsoldering those pins turned out to be the hardest piece of the exercise. After using solder wick to get most of the solder off I had to melt and push down pin-by-pin to get the header off. Then I had to melt the solder and put a toothpick in the hole since it was plated through and didn’t want to give up the solder.
This time the pads on the new board completely aligned with the original board. Soldering was easy except for the different wire lengths due to my hack job wire stripping. I ended up using a 45 year old wire wrapping tool to cut off the insulation without damaging the wire.
After soldering I replaced the battery, hit reset, and then went to check the receiver unit. It had a display of 88.3 degrees (which after recent proximity to the soldering iron didn’t seem unreasonable). That it had a temperature and humidity display at all was a major indicator. The data seemed frozen there. It took about 5 minutes before the data started updating on the display.
The rest was re-assembly and mounting. I did get slightly out of order putting the lid back on the electronics section before re-installing the tipping bucket rain gauge. The lid provides a constraint for the tipping bucket axle. Assembly in reverse of disassembly after that. I installed the unit out on the pool fence and now I have outdoor temperature again.
Result: Success
Status: Back in Service
Tools: Soldering iron, solder, solder wick, various small screwdrivers, camera phone, small gauge wire stripper
Search Note: Sainlogic part EW105DV1 uses and can be replaced by Sensirion SHTC3.
Leave a Reply