LaCrosse anemometer hack

Several years ago I purchased a LaCrosse weather station which had a remote temperature / humidity and anemometer with indoor display. The setup was a little finicky but when it worked, it worked well for several months. And then it wouldn't. Solution was to put everything on the bench, put in new batteries, do the startup thing a few times and maybe it'd hold. And then after a year it died. No combination of new batteries, pushing reset and waiting did anything. I took it down and set it aside.

I've been missing wind speed and direction now for a while, so I did some minor reverse-engineering on anemometer (model TX63U-IT) circuitry and added an ESP8266 which reports back to my server via MQTT.

Here is how the device is wired: the wind speed sensor is a reed switch that closes with a magnet. The wind direction sensor uses four IR LEDs with standard driver configuration and a light pipe that reads if any of the four LEDs are on. The disc on the wind vane binary encodes one of sixteen positions. I chose to cut the control leads to the original MCU from the LEDs and light-pipe along with the reed switch and bring those over to the (now) unused pad for the battery terminals with some 30ga wire.

Code is here: .

I initially had code for a DHT11 sensor but opted to leave it out of the final project as the DHT11 doesn't register below 0C and the anemometer just isn't well sited for temperature. This is powered via a long USB cable but it's somewhere that this isn't a problem. Plus it gets one more low-current USB wall-wart out of the junk drawer. Using batteries and the existing solar panel may have worked but I don't think I could lower current consumption sufficiently.

I chose to use the only analog input pin for the light sensor. I could have probably used a digital input and used the built-in solar panel for some sort of light sensor. In the interest of having this be a one-weekend project -- I didn't.

Unit on bench, encoder wheel under light pipe

additional testing

ESP8266 board tucked into enclosure. It just fits.

Intercepting control lines

This page last modified Sun Aug 15 23:19:09 CDT 2021 by timc!