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. At first glance, thermistors are very simple devices. It is basically 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. 10K […]

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

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 […]

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 […]