Tuesday, August 28, 2018

It Ticks! The Trip Timer Gets Deployed

First there was the prototype. Then hardware failures, followed by hardware successes followed by software failures. But finally, the project is complete: I give you my simple car trip timer:

The timer is hands free, as it's plugged into a USB outlet and turns on when the car turns on. The ESP32 chip and 2.4" display are overkill for this project, but it does give me room to add some cool features. More importantly, it's been a chance to get to know a very functional yet easy to work with set of components. I could see going back to this platform for future projects.

I'm not in love with the color scheme I've currently got going. But fixing that is another project for another day.

I also struggled to develop some sort of case to hold the device, but ultimately left the components bare. This seems to be OK in the car, but future projects will call for a case. Perhaps this is my excuse to buy a 3D printer!

I'm mostly excited that I was able to take this project from vision to functioning device. Hurray for follow thru!

Here's the source code that powers this timer:

/*
 * See:
 *  https://raw.githubusercontent.com/adafruit/Adafruit_ILI9341/master/examples/touchpaint_featherwing/touchpaint_featherwing.ino
 * https://learn.adafruit.com/adafruit-2-4-tft-touch-screen-featherwing/resistive-touch-screen
 */
 

#include <Adafruit_STMPE610.h>
#include <SPI.h>
#include <Wire.h>      // this is needed even tho we aren't using it

#include <Adafruit_GFX.h>    // Core graphics library
#include <Adafruit_ILI9341.h> // Hardware-specific library
#include <Adafruit_STMPE610.h>

#define STMPE_CS 32
#define TFT_CS   15
#define TFT_DC   33
#define SD_CS    14

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);
Adafruit_STMPE610 ts = Adafruit_STMPE610(STMPE_CS);


long started = millis() / 1000;

void setup(void) {
  Serial.begin(115200);

  delay(10);
  Serial.println("Timer Time!");
  

  if (!ts.begin()) {
    Serial.println("Couldn't start touchscreen controller");
    while (1);
  }
}

void loop(void) {
  long remaining = (millis() / 1000) - started;
  int hours = remaining / (60 * 60);
  remaining = hours == 0 ? remaining : remaining % (hours * 60 * 60);
  int minutes = remaining / 60;
  remaining = minutes == 0 ? remaining : remaining % (60 * minutes);
  int seconds = remaining;

  int fg = textFg(hours, minutes, seconds);
  int bg = textBg(hours, minutes, seconds);
  int y   = (tft.height() / 3) - 60;
  
  tft.begin();
  tft.setRotation(2);
  tft.fillScreen(fg);
  tft.setTextColor(bg);
  tft.setTextSize(7);

  showTime(tft, hours, "h", y);
  showTime(tft, minutes, "m", y + 90);
  showTime(tft, seconds, "s", y + 180);
  

  delay(750);
}

void showTime(Adafruit_ILI9341 tft, int value, String unit, int y) {
  tft.setCursor(40, y);
  if(value > 0) {
    if(value < 10) {
      tft.print("0");
    }
    tft.print(value);
    tft.print(unit);
    tft.println();
  }
}
int textFg(int hours, int minutes, int seconds) {
  int red = minutes/2;
  int green = 61 - minutes;
  int blue = 31;
  return ((red) << 11) | ((green) << 6) | blue;
}

int textBg(int hours, int minutes, int seconds) {
  return ~ textFg(hours, minutes, seconds);
}

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