I decided to make my own Air Purifiers.
The project is a basic idea, what can be done with hand tools and as cheap as possible. This is a single-fan filter, in the stores the prices of these devices are very high. I looked at several projects until I make my idea. I decided to buy a filter, not to make a filter (maybe I will make a filter in the next version). I'm using a P1 HEPA system filter. For the fan I use - Arctic 120mm PWM. I decided to do a control with NodeMCU - Arduino. My idea was to make an hourly schedule, when to blow strong and weak. I also added a temperature sensor, as there were free pins on the board. I am also waiting for a Dust Sensor PPD42NJ to see if there is a result of everything I did. The biggest problem is the management of the PWM FAN. It took me a long time to make it work and and also a long time to make it work hard.
Materials used:
Prices are approximate and by memory.
This is the Arduin code
https://github.com/jasenpashov/Arduino-read-out-an...
What I understood based on my practices and on of many attempts
TEST CODE:
int fanPulse = D3;
int fanControl = D2;
unsigned long pulseDuration;
int p = 0;
void setup() {
Serial.begin(9600);
pinMode(fanPulse, INPUT);
digitalWrite(fanPulse,HIGH);
pinMode(fanControl, OUTPUT); }
void readPulse() {
pulseDuration = pulseIn(fanPulse, LOW);
double frequency = 1000000/pulseDuration;
Serial.print("pulse duration:");
Serial.println(pulseDuration);
Serial.print("time for full rev. (microsec.):");
Serial.println(pulseDuration*2);
Serial.print("freq. (Hz):");
Serial.println(frequency/2);
Serial.print("RPM:");
Serial.println(frequency/2*60);
}
void loop() { analogWrite(fanControl,1200);
delay(5000);
readPulse();
analogWrite(fanControl,200);
delay(5000);
readPulse();
}
Sources:
https://handyman.dulare.com/client-server-communic...
https://codebender.cc/sketch:177208#PWM_Fan.ino
http://forum.arduino.cc/index.php?topic=18742.15
http://www.beefrankly.org/blog/2011/12/21/read-out...
https://www.picmicrolab.com/arduino-pwm-fan-contro...
http://www.theorycircuit.com/reading-dc-fan-rpm-ar...
https://www.avrfreaks.net/forum/control-pwm-pc-12v...
https://www.instructables.com/id/OPEN-SOURCE-AIR-PURIFIER/