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 […]
Category: Thermometers
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 […]
Looking for stable PT100 readings
In a previous post I explained how I used the MAX31865 with a Wemos D1 Mini to read a PT100 sensor. This worked, but initial readings were erratic. Readings were also off by about 1 degree C. Almost two weeks later, I have tested 3 different PT100 sensors. I now have an Arduino sketch running […]
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 […]
Project Apogee part 1: fan aspiration
My big project for the summer of 2021 is adding a fan aspirated radiation shield to my setup. My primary shield – the Barani MeteoShield Pro – is a superb product, but a passive shield it remains. It suffers from overheating in windless conditions. Those conditions do not occur too often at my location, but […]
Monitoring radiation shield performance
Spring is here. Today was the first ‘warm’ day (> 20°C) of the year. Conditions where solar radiation errors will start cropping up in the temperature data. Accuracy of temperature readings is a surprisingly complex subject. But any attempt to get accurate readings starts with shielding the sensor from direct or indirect sunlight and ensuring […]
Upgrade to the SHT35
Around New Year’s I took the time to finally bring a new Sensirion SHT35 temp/hygro sensor online. It’s an upgrade compared to the SHT31 sensor chip Davis uses for their Vantage Pro 2. On top of it being more precise (+/- 0,1 C in stead of 0,3 for the SHT31) it also registers an extra […]