Tech-TX

// A simple test to exercise PWM, Tone and Servo functions, all controlled from the terminal.
// All PWM sources and WiFi are initially disabled, individually enabled from the terminal.
// If you have an RC filter on one of the PWM pins, you can read it at the A0 analog input.
// A 200-3K res & 10uf cap R-C work @ 500-40KHz PWM.  Make sure your board supports 3.3V Ain!
//
// This code is released to the public domain with no guarantees whatsoever
// "If it breaks in half, you get to keep both halves." ~ George Carlin

#include <core_esp8266_waveform.h>  // so we can independently disable PWM sources
#include <ESP8266WiFi.h>  //the main WiFi routines

Tech-TX

Objective of the design: use inexpensive components to produce a cleanroom-style particle counter that can be run semi-continuously, monitored from outside the cleanroom.

The 攀藤 (PlanTower) PMS5003 (fifth generation) or PMS7003 (seventh generation) dust sensor costs $15 to $22 on eBay from Shenzhen suppliers.  It samples 0.1 liter and calculates dust particles in > 0.3um, 0.5um, 1um, 2.5um, 5um and 10um bins.  In order to get a useful reading in a cleanroom, we need to add the results from 100 samples (10 liters of air) or the counts are too small to be reliable.   ISO 14644-1:1999 specifies counts in 1 cubic metre of air, which would require 10,000 samples from this small sensor.  100 samples takes roughly 300 seconds to process, so sampling 1 m3  would take 500 minutes (8.3 hours).  As this device is not intended to be a NIST-traceable particle counter, sampling at 1% should give a reasonable estimate of the cleanroom quality.  Note that the two smallest particle bins have up to 50% uncertainty; the larger

Tech-TX

#include <ESP8266WiFi.h>
#include <Schedule.h>
#include <PolledTimeout.h>

const char* AP_SSID = "";  // your router's SSID here
const char* AP_PASS = "";  // your router's password here

void setup() {
  Serial.begin(74880);
  while (!Serial);

Tech-TX

#include <Schedule.h>
#include <PolledTimeout.h>

#define WAKE_UP_PIN D3  // D3/GPIO0, can also force a serial flash upload with RESET
// you can use any GPIO for WAKE_UP_PIN except for D0/GPIO16 as it doesn't support interrupts

void IRAM_ATTR wakeupPinIsr() {
    schedule_function([]() { Serial.println("GPIO went from HI to LO"); });
}