During previous summers I have always been busy with temperature sensors and radiation shields. This year, I have shifted my focus to precipitation. The main reason why I find this interesting is that our warm seasons have seen quite a few dry spells over the past few years. This causes all sorts of issues, but…
Category: Arduino
Good barometers: the BMP388 and BMP390
Barometric pressure is considered to be one of the less interesting metrics to measure with a personal weather station. As a factor in global weather predictions it is very important, but in terms of current conditions we learn a lot more from our thermometers, anemometers, rain gauges and other sensors. Especially if we are considering…
Reading fan speed from the Barani MeteoShield Pro fan-aspirated model (FARS)
In this post, I explained how I use a Wemos D1 Mini microcontroller and a MOSFET module to control the fan speed of a wired fan-aspirated MeteoShield Pro from Barani Design. I am also testing a model with a fan powered by solar panels. Both come with two additional wires connected to a reed switch…
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 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. 10K…
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…
Project Apogee part 3: controlling the TS-100
In my previous post I addressed the power supply needed to run the Apogee Instruments TS-100 fan aspirated shield in my setup. The next step is building a controller for the fan that allows me to vary the fan speed and read the actual rpm being achieved. The idea is that the controller can query…
Project Apogee part 2: power supply
Project Apogee requires me to rethink the power supply of my weather station. When I start writing this, the Meteodrenthe weather station runs on solar power only. The Davis components have their own panel inside the transmitters. Other custom elements use 2 watt 6 volt panels by Voltaic Systems. This has been an ideal solution…