ndnping Jewelry on ESP8266

Junxiao Shi

2017-05-10

I was wearing a unique piece of jewelry at NDN community meeting, Mar 2017: a pair of ESP8266 units that communicate with each other over the NDN testbed. They are ugly, but it is a nice way to demonstrate my creation in a Named Data Networking community meeting.

Two Witty Cloud boards are tied to my wrists, and powered by a USB powerbank in my pocket. One of them runs a ndnping client, and the other runs a ndnping server. The client sends Interests to a router in Arizona, the Interests (under a multicast prefix) are flooded through the testbed, and reach the server which is connected to a router in Memphis.

Arduino Code

Library: esp8266ndn

(read more)

Count-Up Timer on ESP8266 and I2C LCD

Junxiao Shi

2017-05-09

I need a count-up timer on the desk so that I can do a presentation without turning my head to the wall clock. So I wrote one with ESP8266 and I²C-connected LCD unit.

photo of LCD count-up timer using ESP8266

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x3F, 16, 2);

void
setup()
{
  lcd.begin(16, 2);
  lcd.init();
  lcd.backlight();
}

void
loop()
{
  int seconds = millis() / 1000;
  int minutes = seconds / 60;
  seconds %= 60;

  lcd.clear();
  lcd.print(minutes);
  lcd.print(':');
  if (seconds < 10) {
    lcd.print('0');
  }
  lcd.print(seconds);
  delay(100);
}

Hardware is Losant LCD Kit. I'm using Marco Schwartz's LiquidCrystal_I2C library.

(read more)