Using Ecowitt weather sensors often means using their WiFi gateway to process sensors updates. It offers a web interface that allows you to configure several weather services like Weather Underground, Weathercloud and others. But what if you have other plans with your data, like exporting it to your own database? There are several ways to […]
The B parameter vs. Steinhart-Hart equation
In my previous post about reading thermistors with a Wemos D1 Mini, I observed resulting output seemed a bit high at lower temperatures, while readings were lower compared to other sensors at higher temperatures. (If you haven’t read that post yet, you may want to check that first in order to understand the starting point […]
Getting accurate NTC thermistor readings with a Wemos D1 Mini
A thermistor is a very common type of thermometer. They are cheap and readily available in many forms. Thermistors are are simple devices. A thermistor is basically nothing more than a resistor that changes its resistance with temperature. Very popular are 10K NTC thermistors. Negative Temperature Coefficient (NTC) means that resistance drops when temperature rises. […]
Trying out a Vaisala DTR504
I’ve pretty much settled on my current radiation shield setup. Based on personal research alongside that of others, I do not think I will find an affordable radiation shield that can outperform the Barani MeteoShield Pro. Whenever I have doubts about radiation errors, the results produced by sensors inside my actively ventilated Apogee TS-100 will […]
Active versus passive ventilation under high radiation
It’s June. An ideal month in the Northern Hemisphere to observe the effectiveness of radiation shields under high solar radiation. Two of my main sensor setups are a passively ventilated Barani MeteoShield Pro with an SHT35 sensor and the actively ventilated Apogee TS-100 with PT100 sensor. In theory, there should be situations where the Barani […]
Temperature sensor responsiveness (part 2)
In February I wrote a post about the responsiveness of the temperature sensors I am using. One caveat I noted then, was that I was comparing SHT35 sensors with PT100 sensors while the latter were actively ventilated and the first were not. In the mean time I made a few changes to my setup. Most […]
Temperature sensor responsiveness
The passing of a sharp weather front, accompanied by a sudden increase or decrease in temperature, is a good occasion to analyze temperature sensor behavior. Especially apparent becomes the responsiveness of different sensors. February 4th 2022 didn’t see any spectacular weather, but during the afternoon a cold front passed over which caused a very abrupt […]
Uploading to the Weather Underground API
Since all data processing for Meteodrenthe is custom made, this includes sending updates to Weather Underground (WU). I realize that the name of WU has been tarnished in recent years. Nevertheless, it is still one of the most popular websites for PWS owners. Meteodrenthe uploads data there as well. This PWS page is updated once […]
PT100 measurements: MAX31865 vs 4-20 mA
Since very recently I have two identical PT100 sensors set up inside the same fan-aspirated shield. The first sensor is read using the Adafruit MAX31865 breakout board, while the second is linked to a 4-20 mA current loop transmitter. In both cases, a Wemos D1 Mini microcontroller is used to process the signal. For the […]
Using a 4-20 mA PT100 transmitter
In this post, I explained how I used an Adafruit MAX31865 clone in order to read a PT100 temperature sensor. Since then, I’ve tested an original Adafruit version as well. Accuracy from this board is a lot better. While I had to add a calibration offset of somewhere between 0.8 and 1.5 degrees to configurations using the […]