Tag: Measurement

Voltlog #276 – What Is The CO2 Concentration In Your Home?

Welcome to a new Voltlog, in the previous video I showed how I built this monitoring system for CO2, it’s based on an ESP32 development board and it uses two sensors the MH-Z19B and the CCS811. In that video I explained the differences between these two sensors so please watch that to better understand the current video and the conclusions presented here.

I’ve let the system run and collect data for the past few days and now we can take a look at the data and draw some conclusions which might help you decide what sensor to use in your future projects or it might determine you to build a similar data logger to check the CO2 levels in your home because I assure you if you do not have a ventilation system, chances are you are sleeping in some high CO2 concentration levels.

Voltlog #275 – CO2 Concentration Measurement System With MH-Z19B & CCS811

Welcome to a new Voltlog, you might remember these two sensors from a previous mailbag, this is the MH-Z19B and this is the CCS811 both of these report CO2 levels but they measure this differently and I’ll explain this in a moment. I got these two sensors in order to monitor CO2 levels in my home, to determine if the levels rise too much at night, especially during the winter time when we tend to keep the windows closed most of the time. I live in an old apartment building where there isn’t much provision for ventilation and so I suspect the air I breath during sleep is high in CO2 levels as it builds up over night.

In this video I’m gonna show you how I built the monitoring system using an ESP32 board that reads the sensor data and then sends it over the network to an MQTT server running on my raspberry pi. I then use node-red to insert the data into InfluxDB and then finally Grafana to monitor all of this data in a nice graphical user interface. The beauty of this setup is that all of this software is free to use and open-source.

Voltlog #266 – How To Check If Your Raspberry Pi 4 Is Throttling CPU

Welcome to a new Voltlog, today my raspberry pi 4 is again in the spotlight because I want to show you the different scenarios where the board could be throttling down the CPU frequency and how you can identify those. Because it might be a case where your raspberry pi is running slow on a particular task and you don’t know why because there is no built-in mechanism to let you know when the board is throttling down. There are logs which you can check but let’s be honest, few people actually check the logs for something like this.

Throttling of the cpu frequency occurs for good reasons, to protect the board or the cpu from overheating or to prevent any errors from occurring in the case of an under-voltage scenario which may lead to data loss or corruption. Luckily there is a way to check if your system is under one of these conditions, you can run this command on your raspberry pi.

Voltlog #264 – Passive Heatsink Cooling For The Raspberry Pi 4

Welcome to a new Voltlog, here is my raspberry pi 4 which I got a few months ago when they released it and if you have one you might have noticed it gets quite hot especially when it has to do some processing. This newer processor, will get hot quick and the board alone cannot cope with all of this heat so what does it do? Well when the CPU temperature reaches 80 degrees Celsius it will start throttling down the CPU as a way of protecting itself from overheating and this will result in a loss of performance.

The Raspberry Pi 4 has a 1.5GHz quad-core 64-bit Arm Cortex-A72 CPU, that’s roughly three times the performance of the raspberry pi 3 cpu. That inevitably generates more heat. In the original plastic case just sitting idle, connected to a network, doing pretty much nothing, the raspberry pi4 when compared to a raspberry pi3 runs about 12 degrees hotter.

Voltlog #218 – Shower thermometer teardown after 10 months of usage

Welcome to a new voltlog, today we’re going to be doing a bit of a destructive teardown on this shower thermometer. You might remember this from 10 months ago in voltlog #172, I got it 10 months ago and ever since it’s been running in my shower and I’m interested in seeing how this looks on the inside after 10 months of usage.

After about 2-3 months of usage I’ve noticed I was getting different temperature readings for the water that I was previously considering warm enough but at that time I figured it was because of the change from summer to winter and I blamed it on the ambient temperature. However I now checked with a thermocouple and the result was pretty bad, the shower thermometer is way out.

Voltlog #131 – Measuring The Efficiency Of The Ruideng Kis3r33S DC-DC Converter

You might remember this small module from the previous InTheMail, this is the Ruideng dc-dc converter with a claimed efficiency of 95%. Now a figure of 95% efficiency is not unheard of these days, many dc-dc converters can achieve this with proper circuit design.

This particular model uses the MP2307 converter chip manufactured by Monolithic Power and if we take a look at their datasheet we can immediately see where they got the 95% efficiency figure they advertise.

If you own fancy equipment like a source/measure unit than one instrument can do all the measurements and data log the results as well but a source/measure is out of our budget so we will be using multimeters for this test.

Here are links where you can find the equipment used in this video: