Greencheck.nl

Intro

Dit is de nieuwe website ter promotie van de Markermeer Zonnecentrale. Het plan is om een grote zonnecentrale te bouwen op het Markermeer met inbreng van alle nederlandse gemeenten, die dan zelf over de gewonnen energie kunnen beschikken. Het Markermeer is rijksgrond, het rijk beslist er over, en het is dus de hoop dat dit gebeurt.

Nodig mij uit voor een presentatie! App naar 0644311561

Het Project

Er zijn veel details te melden wat betreft dit concept, deze zullen in andere blogposts worden ondergebracht (net als op de orignele website). Niet alleen kun je energie opwekken, dwz stroom en warmte, maar ook woningen realiseren, recreatie gebieden en jachthavens, viskwekerijen.

• Energie opwekken
• Drijvende woningen
• Vis productie
• Recreatie

De kosten zullen over jaren gespreid zijn en men kan externe partijen interesseren om mee te bouwen (zoals Tata en Meta). Ook kan innovatie op gebied van zonnepanelen veel in de kosten schelen.

Technische details

Voorbeelden drijvende zonnecentrales

Als u contact wil opnemen kan dat via email naar frits@rincker.nl ovm de Markermeer Zonnecentrale

Seaweed is a fast growing plant that can produce many tons of dry mass, while sequestring many tons of CO2 every year. The farming practice is part of the ”Blue economy” that is now being developed around the world. Greenwave is an production oriented initiative that is helping off shore farmers around the US with so called 3D and vertical farming.

In Holland seaweed, or algae grown on manure are allowed in the animal food chain, a company (Ingrepro) produced it a while back but has stopped. Seaweed is better as animal feed, although it can not be super easily digested, it produces less methane. Even mixing in some seaweed can reduce methane emissions.

There are some seaweed initiatives that want to grow the plant on land, that approach is high input, part of the fossil fertilizer economy, and not sustainable. Usually this involves growing high value plants that sometimes have been genetically altered. There certainly is a justification for it.

Then there are number of projects set up with some support of the state, but also because the product has a market.

Zeewaar is a farm located at the Jacobahaven on the Westerschelde.

Yourwell is a farm located in Hellevoetsluis on the Oosterschelde

Dutch Seaweed Group has an office in the Jacobahaven and grows on the Oosterschelde

The Seaweed Company (in Schiedam)

Over the world there are many seaweed companies popping up now..

Robot seaweed companies are most interesting.

For ocean carbon sequestriation there’s even a website OceanCDR

Comically Putin now wants ‘non-friendly’ states to pay for Russian gas in Roubles. I am not totally expert on the ownership of the gas, the way it is trade but let me lay out why I think that is comical.

Russian gas is produced in Russia, then brought to the ‘market’ to be traded away. That market is run by the banks, who need to finance deals (which is a great way to lock people into fossil btw.). If the gas is sold in Euro the seller of the gas has Euro to spend, if it is sold in Rouble (or Rouble), the seller has Ruble in his her account.

The banks that exchange ruble for Euro or USD of whatever, they now have a lot of spending power in Europe. Of course this can be the russian state bank, but it doesn’t have to be. My question is : How much of those Euro’s and other non-russian currencies end up in the hands of the russian government?

The reason to ask this is because only foreign currencies have real value in russia, especially at the moment. Russia can print all the Roubles it wants any time so it really doesn’t need them. What sense does it make to sell gas and ask something in return that you can create yourself? No seriously?

It seems the ones getting away with a fortune will be the banks that exchange Euro etc. for Roubles. They are left with reserves of Euro they can lend out. They can recieve Rouble reserves from anyone in Russia, so maybe this is a way to secure global financial access to large Rouble holders (oligarchs) in Russia? The state is not likely to profit much, its effectively giving its gas away, because no matter what, Europe can print Euro’s, buy Roubles and have the gas..

My thoughts wander off to what can be done with the oceans quite often. The basis of my reasoning is that a good solution to capture CO2 is biological in nature, so using growth of some organism and not much else. This option exists, now less than in the past, but still, in growin seaweed and seagrass and perhaps other materials on the ocean.

Another motivator to do so would be that it could shade the oceans, thereby protecting it from warming up further, and reducing evaporation. Of course most people will say its rediculous to even contenplate having an impact if you consider the size of our oceans. They are immense. But who knows. If there existed a salt water variety of duckweed, maybe the oceans could be covered by them and a lot of CO2 could be stored. Strangely there aren’t many floating ocean plants.

So my thinking goes along the lines of floating rafts that are used to grow plants, maybe bamboo growing on bamboo. Maybe some grass growing on floating matts of grass. This method could be extended in size as long as the grass produced would be more than the grass used. Processing the material grown to create parts of the raft or frame would make it a self sustaining operation.

Such an idea is nice, but how or where to start? Currently the “blue economy” is being developed with massive fossil input, because the companies that want the money allocated to the cause are always ones out of the fossil economy. A super poor country (but with land and biomass) might make different choices. How would I get started? I figure Vietnam to have the desired coast (shallow water) which is necessary to fix rafts for my purpose.

Another option is just to float in the middle of a gyrus. The so called ‘Great Pacific Garbage Patch’ is one of them. The advantage could be a good supply of plastics to work with. Getting there and getting going would be a life decision, and doing it alone would be very hard. Involving others would require a solid plan, but there are unknowns. Unknown unknowns. I feel like exploring this for real though. What are your thoughts?

This seems a topic way out of my league, but bear with me. Recently Thad Roberts published an amazing book about the 44 derangements, where he explains that if you take the minimal persistent ‘flow’ of an assumed quantum liquid, which is a hyperbolic figure eight knot, you end up with nearly all constants of nature including partical masses etc. Truely mind blowing and Noble Prize wothy imho.

What this means is that our world consists of undulations of flow in a ‘fluid’ which create all the phenomena we observe. All of them. The liquid itself is still a mystery, but what it has to be, Stephen Wolfram thinks its a graph of some kind, a network with simple rules. Thad’s calculations strongly suggests it consists of spheres, but that may be an artifact of the connecting ‘edges’ having whole number multiple lengths. ‘Energy’ is stored in the compressing of those edges (I wrote about this before), where they can overlap, but will un-overlap as soon as the surrounding forces allow it to. If this is true you are left with a network of vertexes and edges where the edges redistribute according to simple rules. But this level of reality is anything but mathematical. It is computational.

The impulse to say computational stems from our inability to understand action without an actor. We don’t get that the universe can be a network that reconfigures itself at incredible speed (Planck time) and scale with no resistance whatsoever. For us everything requires effort, anything that happens has to have a cause and an effect. This is because of the rules that govern the behavior of the edges and vertexes. If edges could be compressed and then lost, we’d see energy disappear from our universe, and the universe would stop existing really quick. Its really tantalizing to think about this substrate, which expanded after the big bang (according to some).

All the same but a liquid, rapidly reconfiguring network who’s properties we can barely assess does not allow any mathematical reduction. It requires iteration, the evolution of every vertex and edge towards a new configuration. You could claim this to be a function, but how would you define the location of the vertexes without spatial coordinates (the location has to play a role)? What if it really is just a liquid of rigid spheres that repulse each other. We calculate liquid dynamics as flow and density for volume ‘pixels’ but then you always end up with an average. Would be fun to calculate the computational requirement to simulate a piece of simplified universe (repellent liquid) on a computer. Alternative one can build a universe computer.

The universe computer tries to mimic the quantum fluid using some means. I’m trying to work out what it would have to look like.

We need to fight against energy poverty, climate change and ecological destrution by industry and the growing severity of weather patterns. We are constrained by several factors, namely energy availability (ignoring cost), skilled manpower and technology. If you don’t have a chip to make a sensor work, you have no sensor, if you can’t weld a machine together, you have no machine. I’m not mentioning a functioning supply chain, the breakdown of which is another risk we are all exposed to in a globalized economy. We should work towards a society that has no needs from over the horizon.

The first thing I want to stress is that biological solutions are best, because they are cheap. Life (contrary to what many believe) is not creating its own fertile ground, it is a pure opportunist. When life can not thrive it simply does not exist. Large parts of the planet could be hospitable to more life (storing more CO2) but geological features make it so the opportunity (combination of water, nutrients, sunshine etc.) never arise. Humans can change this, and thus the amount of biomass can be increased without much much effort. The Biomass return on energy invested (BROEI?) could be calculated in many cases. Lots to do, and probably done already.

Technical solutions, innovations, are not free in our global fossil based economy, this is why I can list a number that have been killed by banks who rather see products with high cashflow that do not reduce fossil consumption (which also generates constant cashflow) on which banks rely for their operation. Without fossil fuels no modern banks! So energy solutions that are low fossil input, last long, replace fossil consumption have been killed off in recent decades, there are many examples, but here are some.

Wind for heating or cooling

Heating using wind is perfectly possible, its not done anywhere as far as I know. Cooling as well. The design of such a device is simply a turbine with a resistive heater (brake disk) in its nacelle or if you want to make it more complicated, one with a hydraulic pump who’s hydraulic pressure can be used elsewhere. I wrote about the Dutch Rainmaker (a wind cooling system capable of generating 6 m3 water in the desert by condensation). The inventor at the time was pused into the direction of RO by cost concerns, and his turbine would be deployed on an unihabited island in the caribbean, this is what happens when banks get their hands on such an idea. So turbine blades, hydraulic pumps, cooling that runs on hydraulic pressure, or easier still, wind to coolant compressor, water.. Equally for heating. See Windheatingsystem.com

Heat/cold storage in phase change materials

Phase change materials exploit the extra heat that is produced or needed for materials to freeze or thaw. Water turning into ice actually loses more heat at the transition per degree cooling than on the way to zero and from zero to lower temperatures. If you melt it you need more heat to get over this transition. There are many materials that take a long time getting away from the transition temperature, which can be at zero Celsius but also at 30 Celcius or 40 Celsius depending on the material. This means you can store energy in these materials to come out at transition temperature. These materials are usually cheap. Paraffine, Water, Salts. The products made with them however are relatively expensive, see for instance Sunamp storage. If you want to store heat this is a great way to do it.

Many laws prevent heat/cold sharing between houses to not confuse the administration of the energy supplier, this should change.

Water generation by cooling

The above shows one energy source for cooling air so that water in it condensates, but other means can be used, even solar heat! Extracting water with dew nets is another option. Radiative cooling to space (a surface exposed to the clear sky) at night and even during the day means you can cool materials even in full sunligt (if the surface is highly reflective). In the Middle East ice ponds where shaded basins with water that would cool to very low temperatures against the cold sky (63 K)

Freeze desalination

Desalination by freezing water is underused because it requires less energy (and our economy maximizes fossil cashflow, will stop repeating this mantra now). Ice drives off included salts, so you can reach drinkable water by repeated freezing cycles.

Insulation with Vacuum

Vacuum is a very good thermal insulator, most insulation is about using still air to slow down the transmission of cold or heat. Vacuum transmits no cold or heat. The quest should be on for the lightest thinnest way to create a panel holding a vacuum, obviously raw material cost would be low, the product is light and thin. I have seen several companies trying to market it, without much luck.

Ultra High Vacuum Solar Thermal Panels

Vacuum insulation can also increase the yield of solar thermal panels, to where they produce supercritical steam (500 Celsius!). There have been several attempts to market Ultra High Vacuum Solar thermal panels in the past, but either the requirements or the market discouraged their entry. This is a missed opportunity because higher temperature solar thermal heat can be turned into other energy forms with more efficiency, and be used in cooling applications. See also TVP Solar

Combining Solar PV and Thermal

The economy has several Rivian style companies that pretend to work on something but never actually seriously make an attempt. Rivian languished 10 years and is now producing 950 vehicles, worried about ramping up. Likewise companies have tried to produce effective combinations of Solar PV and Solar Thermal panels. Obviously a space saver, also a way to monetize the 85% of heat absorbed by solar panels that is no used. There is plenty of room for such a product, just stay away from banks! Installers are also a big obstacle, as are regulations created by the pro-fossil industry. Triple Solar claims to have a product, but did not respond to a recent request for a quote.

Vegetarianism/Intermittent fasting

Quit eating meat means you reduce the emissions of all the steps needed to get it to your plate. You need to watch vitamine B but otherwise its fine. Just quit meat!

Eating less extends the life expectancy by up to 30%. Red meat containing a lot of iron is actually a cause of faster aging as the iron needs to be neutralized. The fasting rage and low carb diets are both geared towards burning body fat instead of carbohydrates. The intermittent fasting is better though, would be even better combined with vegetarianism. The upside is that ketones are good for your mood, your energy levels go up, you are more capable of dealing with the world than when you are constantly overloading your system with glucose.

Build with Wood and Biological Materials

Concrete and cement are energy intensive. Their use contributes significantly to global emissions. Wood can be processed now to build highrises, its a store of CO2, natural. Plant trees and use wood and you will sink CO2 from the atmosphere. The sooner that is done the better. Hemp can be used to insulate. Somehow the clean sterile look has been promoted, but that’s because its most hypnotic, it makes us robotic, focussed and easy to influence. For our happiness and future bio materials are better though.

You can Build and Dig with Electric Equipment now

The biggest problem with the transition to renewables and climate action is that it requires fossil fuels. But many producers of heavy equipment now make versions that are battery/electric, even the most high powered ones. This opens the opportunity of directly powering equipment with solar, allowing work to be done at near zero cost realtive to work done with continuous diesel consumption. More on electric heavy equipment here.

Every few weeks a batch of Starlink satelites is parked into orbit by the Falcon rockets of SpaceX, another 48 put up on march 8th. We’re already at he final number runs into the thousands. They will facilitate high bandwidth internet both through radio waves (Low Earth Orbit to Earth) and Laser (between the satellites). It is an amazingly complex system that depends on constant recalculation and reconfiguration of connections.

This constellation is quite a revolution for several reasons. Its fast because its closer to the ground than usual satellite communication systems, its has the newest technology and can be constantly updated. Its ground stations cost only ~$100 per month and are not clumsy. The network is practically private and especially when the lasers are used, impenetrable and out of reach. One can easily imagine some of the satellites having dual purposes (having cameras directed towards Earth), but it would be hard to know.

Starcoin already exists on CoinMarketCap.com but its unrelated!

Elon Musk’s idea is that by bringing internet to remote places he also brings education to these spots. A lot of times it is not profitable for anyone to create an internet connection. As we see now with the war against Ukraine internet is also used to create totalitarian bubbles. Spheres of misinformation, the people in it have the option to constantly doubt the news or go along and not make themselves target for prosecution. Imagine what will happen if a mobile phone sized ground station is available, if that is possible (given the bandwidth limits dictated by physics). I could also see it used as a GPS system, along with GPS, Glonass and the European constellation.

Now there’s another option that could benefit from Starlink satellites unique ‘location’, a crypto ledger run on the satellites themselves. The reason we have crypto originally was to design a system that could not be corrupted or owned. It turns out that too much energy and hardware is involved such that its more efficient to channel transactions through several brokers and use exchanges that do not actually trade coins when you trade them at all times etc. The original purity of crypto got lost in scaling and commercial restrictions. It would be simple to start a ledger on servers located in space, which could require a lot less hashing because there’s no other network up there, and because the hashing was done to select a winning node, and the Starlink network would not be competing for coins itself.

Starcoin could be the lowest cost crypto system in operation, powered by solar. Transactions would be made towards IP addresses of servers on the satellites, and the data would be kept in orbit. It would perhaps require more energy than the current sattelites but this just requires a redesign. The currency would be instantly global, access could be lisenced through local providers with a Starlink dish or telecom companies. The value of the currency could be linked to renewable energy exchanges but that needs to be given more thought. Renewable energy is hyper local usually, so the mobility of Starcoin (existing ‘in the constellation’) does not match the mobility of renewable energy like that of the USD matches that of fossil fuels (which makes the world economy such a big mystery most people haven’t even noticed yet), maybe RE will be able to work in the same way if like fossil fuels, groups of countries agree to a single ‘market’ price over a wide territory.

I did not expect Putin to invade Ukraine. the way Russia goes about it now it is happening is painfull to watch. A russian analyst (bad source but ok) said that the planners approved every plan because they where told nothing would come of it anyway. You can argue that if Putin had come in convincingly this would have meant less dead soldiers and civilians who are so incredibly brave. Now Putin doesn’t seem to stop or piss off and the whole system of exchange of energy and services is in chaos and uncertainty, while we see innocent people get killed. It is a horrendous crime done to Ukraine.

NATO is responding semi naively. It can not ignore that supplying Javelins and Stingers is an act of war, so it is involved and Putin sees it that way. The mental state of Putin seems a wish to destroy everything to get his way. The question really is if he will be left with anything, or if he is just causing a general mobilization of unwilling russians to battle with the world. Russians are forced to show a Z sign, an invention of the pro-russians who can coerce any russian into doing it because there are enough that will beat up people that fail to show the sign. Its the inverse of a David Star that jews had to wear or the hitler salute you had to give when you saw a Nazi official.

All this madness needs to remain contained imho. The current isolation strategies are severe. Putin is not prepared according to experts. The West is also not prepared. Our gas now needs to come from other places, because we need energy to transition to renewables, if we are allowed to. Now there’s talk about using gas from Qatar, but where will that bring us. Energy independence is not allowed by fatalist pro-fossil regimes. The environment is super treacherous if you really think about security, with all the surveillance technology, drones etc. Good thing though that some countries just can’t make them.

For Europe many actions can reduce the hardship of high energy cost. But for instance fertilizer for food is made with gas, so that’s not going to be cheaper. Measures that use organic resources or require little energy are the best to make. Laws can be changed for example sharing power and heat in a street should be made legal. There is some advantage to making the changes sting because then the response will be stronger, and the benefit bigger in the short term.

Strangely if Russia remains cut off it will have a lot of oil and gas and food (provided climate change doesn’t mess things up). The crops growing in Middle America are in trouble according to recent news, so food shortages in the world can become a real problem. This will be even wors in poor countries (oil price is expected to reach $170+ and poor countries can’t print USD like the US). The focus should be fully on replacing fossil dependency ASAP.

This is a post for people that know something about electronics and logic. Memristors are the missing element in the component options we know, we have resistors, capacotors, inductors, but until recently we did not have a memristor. In logic you can make any expression if you have AND and NOT, or OR and NOT or some other minimal combination. Similarly in electronics you can have any circuit if you have some minimal nr of components. The memristor completes the set of basic components.

What is a memristor? Its a resistor that can be varied and then rememebers its resistance. Its like a tube that widens if a lot of water flows through, and then goes thinner when less water flows through. There is a memory effect, which means that you can store data in a memristor, but unlike most current types of memory the data storage is almost permanent (10 years for current components). Memristors are also called ‘univeral memory’ because of its ‘no power’ memory aspects.

I wrote about this topic before in 2016 “Closer to AI, or Hewlett Packards Memristor Machine”

Because a memristor is an analog device, as it has a resistance that varies non-discretely, it can mimic neural network elements. In AI the paradigm currently is mostly matric multiplications, where you have input signals 1 or 0 which get multiplied by a real number weight (say 0.213124) and is then put through a threshold function turning it into 1 or 0 again.

Memeristors can make this process easier, because a resistor can divide a voltage so that the output is only part of the input. So instead of having to put binary numbers in registers in a CPU or GPU and multiplying them digitally you can just put a 1 on the line of the resistor and add up the voltages that come out on the other hand. The memresistor more or less functions as a passive processing element, setting the value of the memristor ‘redesigns’ the network it will implement. It requires -no- energy to retain the resistive value, where normal memory needs to be refreshed. This is also the danger to humanity of this kind of device.

The above video is quite old, from 2014, and it should in some people trigger an eerie and creepy response. The guy outlines that Hewlett Packard seeks to build a super fast network of super low energy consuming machines to perform functions we now associate with internet and media, but also AI. Memristors are an essential element in this infrastructure, that seems to be intended to dominate our reality.

The problem with this vision is that 1. It does not make us server our needs, it is mainly meant to serve the fossil based economy and distract/program consumers. 2. As part of AI systems these memory banks (which can be gigantic) will not forget. They can not be switched off. If a bipedal android has memristor memory (which it got because it was lower energy and faster) and makes a mistake that is harmfull, it is possible you can’t approach it, you can’t power it down, and if you power it up again, it will continue to do exactly what it did before you shut it down.

What if you computer could not be reset? One error and it had to be replaced. What if it did dangerous things?

Mythic now offers AI accelerator chips that permanently store inference parameters (network weights) in memristor memory. They can not learn, they can only be set and used. It is 100% true these devices will cut cost, save energy, enable lots of cool applications. But they bring an inertia to possibly mobile and dangerous devices that won’t stop doing what they are doing unless you break the chip out of their circuits. It should certainly not be allowed to store personal data in such memory, as the ‘machine’ as HP calls it, should be avoidable, and us humans should be unidentifyable.

The world is not numbers, a higher number or even the same number can represent a different reality

The economy makes it very easy for us, if the number goes up its good, if the number goes down its bad. Like eggs in a basket, you want to have enough, some always want more. But there’s a reality behind those eggs, and that reality is changing in ways the eggs don’t show. First they came from happy free roaming chickens that felt protected from foxes at the farm, eating whatever was around. Now they are inbred, force fed, get their beaks cut, live in squalor of their own filth, die miserable deaths. Now they are dangerous vectors of respitory viri. The number did not change, but reality did. Keep an eye on the use of universal memory and memristors, because its a different reality than the one we are used to now!

You can buy PM (fine particle dust, fijnstof) sensors, but they usually don’t control anything. I wished to have a ventilation system controlled by a PM sensor, so that when my neighbors decided to burn some wood, I would not have to breath in the smoke and PAKS. Luckily you can buy a PM sensor now that proved workable for me, for about 30 Euro, and tried to maka a PM sensor that can be read through Wifi and can in principle switch on and off ventilation or open and close a window.

The problem with PM sensors that use a laser and have a ventilator is usually the interface. The Nova sensor is available with a USB connector, to translate the signal to something your computer can present as a COM serial connection. The next step is to read out the data. This can be done with Python. This then gives your computer access to the data stream. That’s where I’m at now. I found a code example and debugged it.

#!/usr/bin/python
# -*- coding: UTF-8 -*-

import serial, time, struct

ser = serial.Serial()
ser.port = "com9" # Set this to your serial port
ser.baudrate = 9600

ser.open()
ser.flushInput()

byte, lastbyte = "\x00", "\x00"

while True:
    lastbyte = byte
    byte = ser.read(size=1)
    # print("read",byte) #uncomment to see if any data comes in
    # We got a valid packet header
    if lastbyte == b'\xaa' and byte == b'\xc0':
        sentence = ser.read(size=8) # Read 8 more bytes
        readings = struct.unpack('<hhxxcc',sentence) # Decode the packet - big endian, 2 shorts for pm2.5 and pm10, 2 reserved bytes, checksum, message tail
        
        pm_25 = readings[0]/10.0
        pm_10 = readings[1]/10.0
        # ignoring the checksum and message tail
        
        print ("PM 2.5:",pm_25,"μg/m^3  PM 10:",pm_10,"μg/m^3")

The above code is real system level. The baud rate is 9200 and you need to find out what COM port is used (This is on a Windows machine sorry). Then the code above should work fine. If you have no programming environment download Spyder for Python.

The above shows the output from the code, and the effect of lighting a match close to the sensor. You can already send a message from Python to any server or even your phone, for instance if values become to high (fire? smoke?). I was thinking of a practical application to protect my lungs. If you can keep the sensor connected to you PC you can make it report the data to a website, and this way you can make it available for yourself, others and even automatic systems. I wanted to use a Wifi module so view the data from my mobile without using an external website.

I did some thing with the ESP8266 in the past, the ESP32 is more powerfull. It can run local mesh networks (without internet), be a hotspot for internet and do what it does here, serve webpages. It can operate servo’s and lots of other cool stuff. Now the task was to make it read the Nova data. This meant it needed to read the UART (serial output) of the board.

The Nova board has a special connector that I didn’t want to ruin to connect to the ESP32 board. In the documentation and on the board you can find the description of the pin function. We need the TX, RX, GND (which are next to each other) and the 5V pins. I solderd some female connecting wires to them so they could match the pins on the ESP32.

That ESP32 board WROOM 4MB DEVKIT V1, can be programmed with the Arduino environment, you can simply used the USB cable. The Arduino libraries can talk to the different serial ports the ESP32 has (3 in total). The one we use here is UART2. You can see the pins below as RX2 and TX2. The other two pins of importance are the VIN and GND on the top left.

I decided to build a ‘captive server’ on the ESP32, this means the device shows up on your Wifi list, and you can look up a single IP address, where a tiny website is served. This website is to serve the PM values read by the NOVA module. Below is the code. As you can see it only uses generic libraries. I compared the output with the output from the Python code to check if it was working.

#include <WiFi.h>
#include <DNSServer.h>

#define RXD2 16
#define TXD2 17
char buf[200];
float pm25 = 0;
float pm10 = 0;

const byte DNS_PORT = 53;
IPAddress apIP(192, 168, 1, 1);
DNSServer dnsServer;
WiFiServer server(80);

void setup() { 
  WiFi.disconnect();   //added to start with the wifi off, avoid crashing
  WiFi.mode(WIFI_OFF); //added to start with the wifi off, avoid crashing
  WiFi.mode(WIFI_AP);
  WiFi.softAPConfig(apIP, apIP, IPAddress(255, 255, 255, 0));
  WiFi.softAP("PM server http://192.168.1.1");

  // if DNSServer is started with "*" for domain name, it will reply with
  // provided IP to all DNS request
  dnsServer.start(DNS_PORT, "*", apIP);

  Serial.begin(115200); // normal serial output
  Serial2.begin(9600, SERIAL_8N1, RXD2, TXD2); // to read the pm sensor
  server.begin();
}

void updatepmvalues() {

if (Serial2.available()) {
   
   int len = Serial2.readBytes(buf,20);
   pm25 = (float) word(buf[3],buf[2])/10;
   pm10 = (float) word(buf[5],buf[4])/10;
    
  }
}

void loop() {
  
  dnsServer.processNextRequest();
  
  WiFiClient client = server.available();   // listen for incoming clients

  if (client) {
    updatepmvalues();
    String currentLine = "";
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        if (c == '\n') {
          if (currentLine.length() == 0) {
            client.println("<!DOCTYPE html>");
            client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
            client.println("<meta http-equiv=\"refresh\" content=\"3\">");
            client.println("<body><h1>PM values<table><tr><td>PM 2.5 </td><td>:" + String(pm25) + "</td><td> &#181;g/m^3</td></tr><br>");
            client.println("<tr><td>PM 10</td><td>:"+String(pm10)+ "</td><td> &#181;g/m^3</td></tr></table></h1>");
            client.println("</body></html>");
            
            Serial.print("\n"+String(pm25)+" "+String(pm10));
            break;
          } else {
            currentLine = "";
          }
        } else if (c != '\r') {
          currentLine += c;
        }
      }
    }
    client.stop();
  }
}

It took some time to find out how to read the PM values and convert them but in the end it worked fine. I may have left some stuff in the code, and there is certainly room for improvement in terms of interface. The screen refreshes every 3 seconds to show new values.

The ESP32 can also connect to your home Wifi and report by looking up a webpage designed to recieve the data. You could then look up the page anywhere.

Another thing that’s possible that I will actually try is to hook up a switch/relais to the ESP32 and drive a ventilator or window (although I don’t have the hardware for that yet). The above parts cost about 10 Euro together. For now I will look for a place to hang the sensor and ESP32 so I can connect and read the PM values. If you want to order a working combination of the above youc an always ask (but quantities have to be worth it) email to info@greencheck.nl

Update

I found a cheap eCO2 sensor, which does not measure CO2 directly but calculates it. That’s fine for most applications imho. I managed to get it working (connect the Wake pin to GND and check the address of the specific I2C version) with the ESP32, as you can see below. So now its a matter of combining the parts into a switching PPM and CO2 sensor. Uploading data to a database is now easy so one step is to make it easy to set the Wifi credentials. These can be stored in EPROM (permanent memory) once when the sensor is configured.

The possibilities of the ESP32 are such that you can make a mesh network, where the nodes report the measurements, and the switch is central. This uses the ESP-NOW mechanism, with a range of about 500 meter. Power supply to the parts is somewhat of a challenge. You’d like to use solar if possible. Metarial cost of a CO2/PPM switch can be as low as 45,- Euro for non mass production.