Build Instructions

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• 1

  Basic Setup using Raspberry Pi Pico

  We begin by putting together the simplest possible configuration utilizing the MQ135 Sensor and the recently released Raspberry Pi PICO 2.

  Here, we connected the MQ135 Sensor's VCC to the 3.3V Pin of PICO, GND to GND, and GPIO26 and GPIO21 for the analog and digital outputs, respectively.

  This was the sketch we used for Test.

  #include <Wire.h>
  // Define the pins
  const int analogPin = 26;  // GP26
  const int digitalPin = 21; // GP21
  void setup() {
  Serial.begin(9600);
  pinMode(digitalPin, INPUT);
  }
  void loop() {
  int analogValue = analogRead(analogPin);
  int digitalValue = digitalRead(digitalPin);
  Serial.print("Analog Value: ");
  Serial.print(analogValue);
  Serial.print(", Digital Value: ");
  Serial.println(digitalValue);
  delay(1000);
  }

  It takes about 20 to 30 seconds for the MQ135 Sensor to preheat before it provides precise readings. The sensor value in the Serial monitor can be observed by the user using the sketch above. 

• 2

  Level 2- Design

  We made a little enclosure in the Level 2 design that was just 80 x 55 x 30 mm in size. It was separated into two bodies: the Base and the Top Lid part. The OLED screen is mounted in place by the top lid, which also has four screw holes for attaching it to the base body with M2 screws.

  The Firebeetle 2 Board, MQ135 Sensor, Power Switch, and Battery are all housed inside the Base Body.

  We added handles to the left and right sides of the base body to make this enclosure comfortable and easy to hold.

  To make it easier to wear or carry around, we have included a hook-like component that can be used to attach an ID card strap or a keychain to this device.

  We created additional components that resemble the letters O and X and put them on the top lid part of the enclosure to increase its visual impact. To enhance the device's aesthetic impact, both of these parts will be printed in orange PLA, while the entire enclosure will be printed in grey PLA.

• 3

  Why Choose FireBeetle over Raspberry Pi Pico

  For level 2 of this project, we swapped the main microcontroller used, which was the Raspberry Pi Pico 2, to the Firebeetle 2 ESP32-E Microcontroller board.

  A minor space issue within the enclosure was the reason for this switch; 

  however, despite the fact that the two boards appear to be almost identical in size, the Pico is really smaller than the Firebeetle. We had to modify the enclosure's design and make it slightly larger because using Pico required the addition of a second board for charging the lithium cell.

  We utilized the Firebeetle to address this issue since it has an onboard lithium-ion cell charging circuit that is driven by the TP4056, a full linear charger integrated circuit made specifically for single-cell lithium-ion batteries.

  The TP4065 was incorporated into the Firebeetle development board, which resolved our space issue. It is perfect for usage in portable devices that need a dependable and effective lithium-ion battery charging solution.
  

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