![](/img/potatoAsToast.png)
Potat0ast  
T-Beam Alarm Clock (with NTP!)
Introduction #
SKIP if you just want the How to.
Microcontrollers can be fairly difficult to get into. For the most part, if I had any project, I would head straight for github and grab either some code to push through the Arduino IDE or something that could be flashed (with some more magical GUI software).
Then, my friend shared with me a project called (Meshtastic)[https://meshtastic.org/] where, using a combination of LORA 915Mhz communication and GPS, you could have an open source device that would let you keep in touch with your party in the great outdoors (without wifi, LTE, or any other more stationary networking resource). I was amazed by what it could do, and I saw that there was just more software to be flashed. So I put in an order for two TTGO T-Beams and waited for them to come in from overseas.
Finally they arrived… but I ordered the wrong ones with no OLED screens. I could probably work with them without the screens, but I was there for an easy ride. So I ordered another 2 (at this point I’m pushing a hundred bucks for some side project I don’t know will even work).
Those show up, I flash them and….. GPS does not connect. Needless to say, I did a bit of Googling but couldn’t find much, so they started to sit there.
Anyway, I needed an alarm because I didn’t want an excuse to keep my phone near my bed (since it is the current alarm in use). That thing is an adult pacifier and probably the most appealing thing next to staring at the ceiling. So instead of buying
I opted to at least make some use of the hundred dollars spent (wasted).
Setup #
So here are some prerequisites we will need before starting:
- Drivers
- https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers for Windows and Mac. From Silabs. Guess we just have to trust it and click next on the install prompts very quickly so the viruses can’t multiply.
- If you’re running Linux, I imagine you already know what to do
- Arduino IDE https://www.arduino.cc/en/software
- VS Code (not required but it’s nice to have)
- Arduino Libraries
- ESP8266 and ESP32 OLED driver for SSD1306 displays (yeah it’s a mouthful). This gets the little screen to work.
- WiFi for the esp32 should be built in
- NTPClient (so time isn’t completely off)
First download the driver and install it so your usb port can communicate with the UART channels on your board.
Unzip the downloaded file, double click on the dmg, double click on the driver installation app, and follow the on-screen prompts to install it.
Once that is installed, also install the Arduino IDE if you haven’t already. Then open it up and you should be greeted with something like this
If you’ve never used an Arduino board before, this is just some template code for the board. Anything in the {} after setup() will be run only once. Anything in between the {} after loop() will be run repeatedly… like in a loop.
In order to get the code onto the T-beam board, we will need to add the particular board type into our Arduino installation. To do this, first head to the preferences or settings for the IDE and look for the field called “Additional Boards Manager URLs”. Add the following URL: https://dl.espressif.com/dl/package_esp32_index.json and open the Boards Manager.
Search for the esp32 (by Espressif Systems) and install it. Go back to Tools -> Board -> ESP32 and select the T-Beam. Now, we have essentially configured everything we need to begin communicating with the T-Beam. You can plug in your T-Beam and begin coding and flashing code to your board. However, for more advanced functionality, it is likely that you would install libraries so you don’t need to learn how to write code to communicate with a specific OLED screen or how to communicate with a networking chip.
Under the Sketch tab, go to “Include Library” and select “Manage Libraries…”
The first library we will install is Timelib so that managing time is easier.
Go to the search bar and search “time” or “timelib” until you find the library shown above. The install button will be in the bottom right if you haven’t already installed the library. Proceed to install all of the following libraries as well:
- esp8266 and esp32 OLED driver for ssd1306 displays: It’s a pretty self explanatory library name, but it basically makes it easier to use the small displays that are used on arduino boards. For example, you can print text to the screen or draw shapes to the screen.
- NTPClient: Contains the code that allows the board to communicate using the network time protocol and get accurate, current time/date.
- WiFi: Contains code to communicate with common WiFi protocols. Should be installed by default.
That is all for the libraries we’ll be needing. Now here is the code. I will try to comment everything as clearly as possible. Otherwise it should just work once you change the wifi details to suit your access point.
#include "SSD1306Wire.h"
#include <WiFi.h>
#include <NTPClient.h>
#include <TimeLib.h>
#include "pitches.h" // see pitches.h file below. It is another file in the same project
// set wifi variables
const char* ssid = "SSID";
const char* password = "PASSWORD";
// set the display
SSD1306Wire display(0x3c, SDA, SCL);
// Define NTP client to get time
WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP);
// Variables to save date and time
String formattedDate;
String dayStamp;
String timeStamp;
// connect to WiFi function
void connectToWiFi() {
Serial.print("Connecting to WiFi");
// set wifi to station mode (client mode)
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, password);
int attempt = 0;
// while loop that adds a dot for each second that the status is not connected yet
while(WiFi.status() != WL_CONNECTED){
Serial.print("."); // print a dot to serial
display.drawString(attempt, 0, "."); // draw a dot next to the last one.
display.display(); // refresh the display so what was drawn actually shows
attempt++; // increase the attempt counter (acts as x axis for dots being printed)
delay(1000);
}
}
// utility function for digital clock display: prints leading 0
String twoDigits(int digits){
if(digits < 10) {
String i = '0'+String(digits);
return i;
}
else {
return String(digits);
}
}
// plays a tone from a particular pin for a set amount of time
void tone(byte pin, int freq, int length) {
ledcSetup(0, 2000, 8); // setup beeper
ledcAttachPin(pin, 0); // attach beeper
ledcWriteTone(0, freq); // play tone
delay(length); // play for as long as specified
ledcWriteTone(0, 0); // then turn off
}
void playMelody() {
// notes in the melody:
int melody[] = {
NOTE_C4, NOTE_G3, NOTE_G3, NOTE_A3, NOTE_G3, 0, NOTE_B3, NOTE_C4
};
// note durations: 4 = quarter note, 8 = eighth note, etc.:
int noteDurations[] = {
4, 8, 8, 4, 4, 4, 4, 4
};
// loop to play the melody specified
for (int thisNote = 0; thisNote < sizeof(melody)/sizeof(melody[0]); thisNote++) {
tone(14, melody[thisNote], 1000/noteDurations[thisNote]);
}
}
void setup() {
// set the baud rate and print newlines to serial
Serial.begin(9600);
Serial.println();
Serial.println();
// initialize the display and set font
display.init();
display.flipScreenVertically();
display.setFont(ArialMT_Plain_10);
connectToWiFi();
// set pin 14 for output
pinMode(14, OUTPUT);
playMelody();
display.drawString(0, 0, "hello");
display.display();
delay(3000);
display.clear();
// show the mac address in serial and on the screen
Serial.print("ESP Board MAC Address: ");
Serial.println(WiFi.macAddress());
display.drawString(0, 10, "ESP Board MAC Address: ");
display.drawString(0, 20, WiFi.macAddress());
display.display();
// show the IP address on screen
display.drawString(0, 40, "ESP Board IP Address: ");
display.drawString(0, 50, WiFi.localIP().toString());
display.display();
// start the time client and set timezone GMT -8
timeClient.begin();
timeClient.setTimeOffset(-25200); delay(5000);
// get the datetime
while(!timeClient.update()) {
timeClient.forceUpdate();
}
// Extract Date and Time
formattedDate = timeClient.getFormattedTime();
int epochTime = timeClient.getEpochTime();
setTime(epochTime);
Serial.println(formattedDate);
// Extract date
int splitT = formattedDate.indexOf("T");
dayStamp = formattedDate.substring(0,splitT);
display.drawString(0, 0, "TIME: " + dayStamp);
display.display();
// save some power
WiFi.mode(WIFI_OFF);
}
void loop() {
// clear the screen and update the time
display.clear();
display.setFont(ArialMT_Plain_16);
display.drawString(0,0, String(hour()) + ":" + twoDigits(minute()) + ":" + twoDigits(second()));
display.display();
// The alarm. This is for 6:25 am. 1430 for 2:30 pm
if (String(hour()) + String(minute()) == "625") {
playMelody();
}
// update the time every so often. In milliseconds
delay(1000);
}
// contains note definitions so you don't need to know specific frequencies. Just a bit of music theory
#define NOTE_B0 31
#define NOTE_C1 33
#define NOTE_CS1 35
#define NOTE_D1 37
#define NOTE_DS1 39
#define NOTE_E1 41
#define NOTE_F1 44
#define NOTE_FS1 46
#define NOTE_G1 49
#define NOTE_GS1 52
#define NOTE_A1 55
#define NOTE_AS1 58
#define NOTE_B1 62
#define NOTE_C2 65
#define NOTE_CS2 69
#define NOTE_D2 73
#define NOTE_DS2 78
#define NOTE_E2 82
#define NOTE_F2 87
#define NOTE_FS2 93
#define NOTE_G2 98
#define NOTE_GS2 104
#define NOTE_A2 110
#define NOTE_AS2 117
#define NOTE_B2 123
#define NOTE_C3 131
#define NOTE_CS3 139
#define NOTE_D3 147
#define NOTE_DS3 156
#define NOTE_E3 165
#define NOTE_F3 175
#define NOTE_FS3 185
#define NOTE_G3 196
#define NOTE_GS3 208
#define NOTE_A3 220
#define NOTE_AS3 233
#define NOTE_B3 247
#define NOTE_C4 262
#define NOTE_CS4 277
#define NOTE_D4 294
#define NOTE_DS4 311
#define NOTE_E4 330
#define NOTE_F4 349
#define NOTE_FS4 370
#define NOTE_G4 392
#define NOTE_GS4 415
#define NOTE_A4 440
#define NOTE_AS4 466
#define NOTE_B4 494
#define NOTE_C5 523
#define NOTE_CS5 554
#define NOTE_D5 587
#define NOTE_DS5 622
#define NOTE_E5 659
#define NOTE_F5 698
#define NOTE_FS5 740
#define NOTE_G5 784
#define NOTE_GS5 831
#define NOTE_A5 880
#define NOTE_AS5 932
#define NOTE_B5 988
#define NOTE_C6 1047
#define NOTE_CS6 1109
#define NOTE_D6 1175
#define NOTE_DS6 1245
#define NOTE_E6 1319
#define NOTE_F6 1397
#define NOTE_FS6 1480
#define NOTE_G6 1568
#define NOTE_GS6 1661
#define NOTE_A6 1760
#define NOTE_AS6 1865
#define NOTE_B6 1976
#define NOTE_C7 2093
#define NOTE_CS7 2217
#define NOTE_D7 2349
#define NOTE_DS7 2489
#define NOTE_E7 2637
#define NOTE_F7 2794
#define NOTE_FS7 2960
#define NOTE_G7 3136
#define NOTE_GS7 3322
#define NOTE_A7 3520
#define NOTE_AS7 3729
#define NOTE_B7 3951
#define NOTE_C8 4186
#define NOTE_CS8 4435
#define NOTE_D8 4699
#define NOTE_DS8 4978