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 […]

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 […]

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 […]

Reading a PT100 sensor with a Wemos D1 Mini

In my never ending quest for better temperature readings – or other ways of doing so, at least – I’ve begun trying other sensors than the SHT35. One of them is the PT100. It’s supposed to be very accurate. It it used in many different situations, from laboratory settings to industry. It’s also used in […]

Apogee TS-100 first impressions

I was losing the last light and had to get a flash light while connecting the last wires Tuesday evening (August 17th), but I have the TS-100 up and running. Without battery backup for now. I will fix that later. Adding this new shield to my setup has triggered a whole series of new tests […]