Change of Plan: Time Zone Converter with Arduino

 I’m terrible with time conversion. Even when it’s simple conversion, for example 12 hour between between Shanghai and New York, I still get confused with the date. My goal is to create a device that will facilitate appointments making across time zones.

On p5.js, I created a tool that allows the user to select a target time zone, and see the time and date there by toggling through user’s local time. I am going to create a physical way to interact with the slider, and the buttons with Arduino Nano 33 IoT.

The device has two parts: p5.js and Arduino. The user will be able to change the source time zone date, hour, and minute, and to choose the target time zone with four rotary encoders / potentiometers. p5.js will then do the conversion and light up one of the two LEDs to indicate AM/PM in the target time zone.

System Diagram

Breadboard

BOM

Component	Quantity ¥	Unit Price
Arduino Nano 33 IoT	1	220
Jumper Wires	1 set	3.69
Breadboard	1	6
Potentiometer	4	3.21
LED	2	2
Resistor	2	2

Demo

Special thanks to Yuchen who helped me debug the code! 

To-do list

1. 1. Find out a way to stabilize the readings so the numbers don’t flash.
      so far I have tested the following code to be working on one reading:
      /*
      SmoothingReads repeatedly from an analog input, calculating a running average and
      printing it to the computer. Keeps ten readings in an array and continually
      averages them.The circuit:
      – analog sensor (potentiometer will do) attached to analog input 0

      created 22 Apr 2007
      by David A. Mellis <dam@mellis.org>
      modified 9 Apr 2012
      by Tom Igoe

      This example code is in the public domain.

      https://www.arduino.cc/en/Tutorial/BuiltInExamples/Smoothing
      */

      // Define the number of samples to keep track of. The higher the number, the
      // more the readings will be smoothed, but the slower the output will respond to
      // the input. Using a constant rather than a normal variable lets us use this
      // value to determine the size of the readings array.
      const int numReadings = 200;

      int readings[numReadings]; // the readings from the analog input
      int readIndex = 0; // the index of the current reading
      int total = 0; // the running total
      int average = 0; // the average

      int inputPin = A0;

      void setup() {
      // initialize serial communication with computer:
      Serial.begin(9600);
      // initialize all the readings to 0:
      for (int thisReading = 0; thisReading < numReadings; thisReading++) {
      readings[thisReading] = 0;
      }
      }

      void loop() {
      // subtract the last reading:
      total = total – readings[readIndex];
      // read from the sensor:
      readings[readIndex] = analogRead(inputPin);
      // add the reading to the total:
      total = total + readings[readIndex];
      // advance to the next position in the array:
      readIndex = readIndex + 1;

      // if we’re at the end of the array…
      if (readIndex >= numReadings) {
      // …wrap around to the beginning:
      readIndex = 0;
      }

      // calculate the average:
      average = total / numReadings;
      // send it to the computer as ASCII digits
      Serial.println(average);
      delay(1); // delay in between reads for stability
      }

      I still need to figure out how to incorporate it into the for-loop so it works on all four values.

2. Add the feature to turn on LED with the output from p5.js to Arduino as a feedback.
3. Add sound effects when turning the potentiometer as a feedback.