Yesterday's temperature high in Phoenix, Arizona was 39C (102F). The interior of one's parked vehicle can subsequently reach 65C+ unshaded from the sun. Stagnant air aides in this elevation and discomfort which was cause for the application of a device for any appreciable deflection of this excess heat.

Plundering from a 10$ child science kit found at most hobby stores (a surprisingly cheaper alternative to individual parts from an electronics store such as Radio Shack) with a delicate drilling and soldering, we have installed an independent solar powered (as to not drain the vehicle's battery) air circulation system.

Prototyping an Arduino sketch can lead to several disconnects and reconnects of the USB cable. This unobtrusive on/off switch hack takes (3) dollar store parts to achieve what is often sold retail for vastly more. A gratuitous USB cable and/or toggle switch may already be some thing presently laying around your shop.

Ingredients
USB Car Charger
USB Cable
Toggle Switch
Paint (Optional)

Recipe
Hard connect GND, D+ and D- to the female USB and toggle the VCC. (USB Pinout)

Last year, we neglected to add our annual Everybody Draw Mohammed Day contribution and with this year's event closing in, we thought we would release our "last year" sketch prior to publishing this year's addition. Allow us, if you shall, a rendition of the meme "Dick Butt", Mohammed Butt...with retsyn.

Reference: Arduino Bowel Gauge

 // Bowel Gauge _ @TVMiller
 #include <LiquidCrystal.h>
 LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

int ssr;
int sensorstart = 0;

void calibrate() {
 lcd.setCursor(0, 0);
 lcd.print("Calibrating...");
for (int x=0, x<10; x++) {
 ssr = analogRead(A0);
 sensorstart = sensorstart + ssr;
  delay(100);
}
 sensorstart = sensorstart / 10;          // Average
 lcd.clear();
}

void setup()
{
 lcd.begin(16, 2);
 lcd.clear();
 calibrate();
}

void loop()
{
  int sensorlive = analogRead(A0);       // Live reading
   int dif = (sensorlive - sensorstart); // Subtract calibrated reading
    float difsol = dif * 0.191;          // Variance to fl oz per 40 oz
     float difoz = difsol * 1.0425;      // Convert fluid to solid ounces

     if (difoz < 0) {
 lcd.setCursor(0, 0);
 lcd.print("0.00");                      // Remove negative fluctuations
 } else {
 lcd.setCursor(0, 0);
 lcd.print(difoz);                      // Print OZ
 }

 lcd.setCursor(6, 0); lcd.print("OZ");
 lcd.setCursor(11, 0); lcd.print("BOWEL");
 
 lcd.setCursor(0, 1);
 lcd.print(millis()/1000);               // Print SEC

 lcd.setCursor(6, 1); lcd.print("SEC");
 lcd.setCursor(11, 1); lcd.print("GAUGE");

  delay(100);
}

Mine are well rounded.