I’ve had a Sainlogic weather station for a couple of years out in the backyard. It has wind speed and direction, rainfall, temperature and humidity. About three months ago the temperature and humidity went out.
The first thing I did was to put new batteries in. The unit has a solar panel that assists the dry cells and extends the life of the batteries so even though the radio reports fairly frequently a set of 3 AA batteries will typically last over a year.
After replacing the batteries I noticed that the other outdoor components (wind and rain) were still reporting, but no temperature.
I actually ordered a replacement weather station unit, but I was ticked that I was spending over $100 to replace basically a thermometer. I really want the rainfall and the temperature. I don’t care that much about the wind and between the house and trees the wind measurement isn’t that meaningful. What surprised me was what a poor selection there was of electronically reporting rain gauges there were. Remote thermometers were a little more common. I had left the replacement weather station in the cart and it just sort of got ordered with other stuff.
I got some free time on an unusually nice February day and pulled the old unit inside.
The thermometer location was obvious because of the stacked and vented sunshade. This tries to keep direct solar radiation out of the temperature reading. Opening the shade and then another vented case inside revealed the temperature and humidity assembly. The board was labeled EW105DV1. I spent some quality time searching for that particular part in hopes I could get a direct replacement (there is one, but not by that number – see Part 2).
It was clear that others had searched for the part because I actually got a hit on the Sainlogic Weather Station. On querying google it said something like “well it may not contain your search term, but it seems related”. Thank you, Big Brother.
A day or two later I tried a search for temperature and humidity sensors. Poking through Amazon I saw a breakout board made for Arduino experimenting that had I2C bus markings like the one that was on the weather station.
Aha! I said to myself and ordered one of the units. Ordered on Saturday and it was on my porch Monday.
The order of the pins was different on the breakout board than on the original sensor. Both were clearly labeled so I cut off the old sensor, stripped wires back (not without accidentally cutting one short), mapped the wires and soldered in the new unit.
NOTHING
I pulled up the specs for the chip on the new sensor. Aha, it has a jumper that lets you set two different addresses so that you can have more than one on a bus. About that time I finally hit the lighting right and took a picture of the original chip (the one shown above) and got the number. Not the same chip.
“Why didn’t you do that in the first place” I can hear you ask. I don’t have a good answer for that.
Comparing the spec sheets there was no way this new chip was going to work in place of the old one. Although electrically compatible, they have different addressing and even communication frames.
Result: Fail
Status: Hope with the right part.
Tools: Assorted small screwdrivers, Soldering iron, solder and solder wick, camera with macro.
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