I was looking for a straightforward clock to use with a 128x64 OLED I got from Adafruit but found that a lot of the implementations were too cumbersome, involved a ton of code, weren't clear on what NTP servers to use and how, and basically offered very little in terms of making a clock with the LOCAL time (not UTC, which is easy enough to get). So I set about doing my own research and ended up with this simple clock that leverages already made libraries to minimize the code footprint, while offering some interesting tweaks in displaying the time (like AM/PM, 12-hour format, names for months, days, etc). This instructable assumes you have some experience programming ESP-01s but if not, there are a ton of wonderful tutorials available on Instructables! Enjoy!
Step 1: Components
For this instructable you will need:
- ESP8266-01 module
- 128x64 OLED with I2C interface
- 3.3V power supply
- A way to program the ESP-01
Step 2: Wire It Up!
The wiring is simple. Just follow the diagram above and connect the wires. Then get a 3.3V power supply (I used a step-down module to go from 12V to 3.3 but you can use whatever you have in your arsenal as long as it outputs 3.3V and at least 0.5 A).
Step 3: Program the ESP-01
This step can be frustrating if you haven't done it before, but once you get the hang of how the ESP boards work and have the correct drivers and libraries installed in Arduino, you can go ahead and use the following code. But first, you will need to download and install the following libraries:
- Time.h & TimeLib.h: https://github.com/PaulStoffregen/Time
- Timezone.h: https://github.com/JChristensen/Timezone
- SSD1306.h & SSD1306Wire.h: https://github.com/squix78/esp8266-oled-ssd1306
- NTPClient.h: https://github.com/arduino-libraries/NTPClient
- ESP8266WiFi.h & WifiUDP.h: https://github.com/ekstrand/ESP8266wifi
You may need to modify some of the code according to what OLED you're using (as long as it's SSD1306 it'll work but you may need to update the hex I2C address) and then you may have to change some of the Timezone rules depending on your timezone and daylight savings time rules. Then upload the code attached and you should be done!
Step 4: See It Go!
Once you have programmed the ESP, plugged everything in, make sure you have 3.3V going into the setup and then power it on and see your correct time on the tiny display!