Embedded Lab

An animated IoT clock shared by Tobozo Tagada does not use any RTC module orconnect to a NTP server to retrieve the time. It rather scans the open WiFi access points in its surrounding and extract the date/time from the “Date” HTTP header, if sent out by some. Trust this clock’s accuracy at your own risk. It uses WeMOS ESP8266 board and an OLED screen to display the time along with a pong animation in the background to “cut on the boringness of the clock”, as he said.

Expecting unknown networks to provide a HTTP header value and relying on it to estimate time is like counting on other people’s wealth to survive, hence the Hobo name.

The exclusive use of open access points removes the hassle of hardcoding SSID/password into the sketch but also compensates its lack of auth plus the fact that the optional NTP connexion attempt will always fail, unless the AP acts as.

The Pong animation with a bouncing rotating cube is there to cut on the boringness of the clock but also to demonstrate how this tiny OLED can animate fast (nearly 60fps).

Since it has trust issues, don’t trust this clock more than you would trust a stranger’s watch! The available space and power consumption won’t let it run more than a couple of hours on the LiPo anyway.