Community project
Abbey Wood Elizabeth Line Times
This project builds a real-time departure display for Abbey Wood station on London's Elizabeth Line. The ESP32 microcontroller fetches live train times from Transport for London's API and renders them on a 300x400 pixel display, updating every 60 seconds to show the next five departures.
The guide provides a complete parts list, wiring diagram for connecting the display to the ESP32, and step-by-step assembly instructions. Builders will configure Wi-Fi credentials, deploy the provided firmware, and mount the board where the display can be easily viewed. The result is a dedicated station information panel that works anywhere with internet access.
Wiring diagram
Interactive · read-onlyPan and zoom to explore the wiring. Remix the project to edit it in your own workspace.
Assembly
4 stepsPlace the board where the display can be lit
Set the Waveshare ESP32-S3-RLCD-4.2 on a stable surface with ambient light falling onto the front of the reflective LCD. This display has no backlight, so it needs room light or daylight to be readable.
- Tip: Avoid mounting the screen face-down or in a dark enclosed box.
- Tip: There are no external display wires to connect; the LCD is already wired inside the board.
- ⚠ Do not expose the board or USB connector to rain, condensation, or conductive surfaces.
Connect USB-C power
Connect a suitable USB-C data-and-power cable from the board to your computer or a stable 5 V USB supply. The same cable powers the board and is used by Schematik’s Deploy button.
- Tip: Use a known-good data cable, not a charge-only cable.
- Tip: If your board has its optional 18650 holder fitted, leave the battery out for initial USB-powered testing.
- ⚠ Never insert an 18650 cell with reversed polarity.
- ⚠ Do not use a damaged, swollen, or unprotected lithium-ion cell.
Prepare the Wi-Fi placeholders
Before deployment, replace the WIFI_SSID and WIFI_PASSWORD placeholder text at the top of the firmware with your 2.4 GHz Wi-Fi network name and password. The screen will otherwise show its Wi-Fi setup message.
- Tip: Keep the quotation marks around each Wi-Fi value.
- Tip: The ESP32-S3 connects to 2.4 GHz Wi-Fi; a 5 GHz-only network will not work.
- ⚠ Treat the project firmware as containing your Wi-Fi password after you add it.
Deploy and view departures
Use Schematik’s Deploy button. Once connected to Wi-Fi, the board requests TfL’s public Abbey Wood Elizabeth line arrivals data and displays the next five services. It refreshes every 60 seconds.
- Tip: Increase room lighting if the reflective screen appears faint.
- Tip: The TfL feed may temporarily show no services during disruption or outside service hours.
- ⚠ This is an information display only; always check official TfL announcements before travelling.
Firmware
ESP32#include <Arduino.h>
#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>
#include <U8g2lib.h>
#include <SPI.h>
#include <time.h>
// Replace these placeholders before deployment. Keep the quotation marks.
// Hoisted type definitions
struct Departure {
char destination[48];
time_t expected;
};
// Forward declarations
bool credentialsMissing();
bool parseUtc(const char *isoTime, time_t &result);
void drawScreen();
void sortDepartures();
bool fetchDepartures();
void connectWifi();
const char *WIFI_SSID = "Speedy";
const char *WIFI_PASSWORD = "guillenDiniz1A";
constexpr char TFL_URL[] =
"https://api.tfl.gov.uk/StopPoint/910GABWDXR/Arrivals?lineId=elizabeth";
constexpr uint32_t REFRESH_INTERVAL_MS = 60000;
constexpr int LCD_SCK = 11;
constexpr int LCD_MOSI = 12;
constexpr int LCD_CS = 40;
constexpr int LCD_DC = 5;
constexpr int LCD_RESET = 41;
// Physical panel is 300 x 400. Rotation R1 presents a 400 x 300 landscape dashboard.
U8G2_ST7305_300X400_F_4W_HW_SPI display(U8G2_R1, LCD_CS, LCD_DC, LCD_RESET);
Departure departures[5];
uint8_t departureCount = 0;
uint32_t lastRefresh = 0;
char statusMessage[56] = "Starting...";
bool credentialsMissing() {
return strcmp(WIFI_SSID, "YOUR_WIFI_NAME") == 0 ||
strcmp(WIFI_PASSWORD, "YOUR_WIFI_PASSWORD") == 0;
}
bool parseUtc(const char *isoTime, time_t &result) {
int year, month, day, hour, minute, second;
if (sscanf(isoTime, "%d-%d-%dT%d:%d:%d", &year, &month, &day, &hour,
&minute, &second) != 6) return false;
tm value = {};
value.tm_year = year - 1900;
value.tm_mon = month - 1;
value.tm_mday = day;
value.tm_hour = hour;
value.tm_min = minute;
value.tm_sec = second;
result = mktime(&value); // setup() explicitly selects UTC.
return result != static_cast<time_t>(-1);
}
void drawScreen() {
display.clearBuffer();
display.setFont(u8g2_font_helvB14_tf);
display.drawStr(12, 24, "ELIZABETH LINE");
display.setFont(u8g2_font_helvR10_tf);
display.drawStr(12, 40, "Abbey Wood departures");
display.drawHLine(12, 48, 376);
if (credentialsMissing()) {
display.setFont(u8g2_font_helvB12_tf);
display.drawStr(12, 82, "Wi-Fi setup needed");
display.setFont(u8g2_font_helvR10_tf);
display.drawStr(12, 108, "Edit WIFI_SSID and WIFI_PASSWORD,");
display.drawStr(12, 124, "then press Deploy again.");
} else if (departureCount == 0) {
display.setFont(u8g2_font_helvB12_tf);
display.drawStr(12, 82, statusMessage);
display.setFont(u8g2_font_helvR10_tf);
display.drawStr(12, 106, "TfL data will retry automatically.");
} else {
time_t now = time(nullptr);
for (uint8_t i = 0; i < departureCount; ++i) {
int y = 75 + i * 40;
long seconds = static_cast<long>(difftime(departures[i].expected, now));
long minutes = seconds <= 30 ? 0 : (seconds + 30) / 60;
char due[12];
if (minutes == 0) strcpy(due, "Due");
else snprintf(due, sizeof(due), "%ld min", minutes);
display.setFont(u8g2_font_helvB12_tf);
display.drawStr(12, y, departures[i].destination);
display.setFont(u8g2_font_helvB10_tf);
display.drawStr(386 - display.getStrWidth(due), y, due);
display.drawHLine(12, y + 10, 376);
}
}
display.setFont(u8g2_font_6x10_tf);
display.drawStr(12, 289, statusMessage);
// This driver transfers the complete monochrome buffer only after a visible update.
display.sendBuffer();
}
void sortDepartures() {
for (uint8_t i = 0; i + 1 < departureCount; ++i) {
for (uint8_t j = i + 1; j < departureCount; ++j) {
if (departures[j].expected < departures[i].expected) {
Departure temporary = departures[i];
departures[i] = departures[j];
departures[j] = temporary;
}
}
}
}
bool fetchDepartures() {
WiFiClientSecure client;
client.setInsecure(); // A CA bundle is not embedded; HTTPS is still encrypted.
HTTPClient http;
if (!http.begin(client, TFL_URL)) {
strcpy(statusMessage, "Could not start TfL request");
return false;
}
const int responseCode = http.GET();
if (responseCode != HTTP_CODE_OK) {
snprintf(statusMessage, sizeof(statusMessage), "TfL request error: %d", responseCode);
http.end();
return false;
}
DynamicJsonDocument doc(16384);
const DeserializationError error = deserializeJson(doc, http.getStream());
http.end();
if (error) {
strcpy(statusMessage, "Could not read TfL data");
return false;
}
departureCount = 0;
for (JsonObject item : doc.as<JsonArray>()) {
if (departureCount == 5) break;
const char *destination = item["destinationName"] | "Unknown destination";
const char *expectedArrival = item["expectedArrival"] | "";
time_t expected;
if (!parseUtc(expectedArrival, expected)) continue;
strncpy(departures[departureCount].destination, destination,
sizeof(departures[departureCount].destination) - 1);
departures[departureCount].destination[sizeof(departures[departureCount].destination) - 1] = '\0';
departures[departureCount].expected = expected;
++departureCount;
}
sortDepartures();
snprintf(statusMessage, sizeof(statusMessage), "Updated from TfL - %u services", departureCount);
return departureCount > 0;
}
void connectWifi() {
WiFi.mode(WIFI_STA);
WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
const uint32_t started = millis();
while (WiFi.status() != WL_CONNECTED && millis() - started < 15000) delay(250);
}
void setup() {
Serial.begin(115200);
setenv("TZ", "UTC0", 1);
tzset();
SPI.begin(LCD_SCK, -1, LCD_MOSI, LCD_CS);
display.begin();
if (credentialsMissing()) {
strcpy(statusMessage, "Add Wi-Fi credentials in firmware");
drawScreen();
return;
}
connectWifi();
if (WiFi.status() != WL_CONNECTED) {
strcpy(statusMessage, "Wi-Fi connection failed");
drawScreen();
return;
}
configTime(0, 0, "pool.ntp.org", "time.nist.gov");
const uint32_t started = millis();
while (time(nullptr) < 1700000000 && millis() - started < 10000) delay(200);
fetchDepartures();
lastRefresh = millis();
drawScreen();
}
void loop() {
if (credentialsMissing()) return;
if (WiFi.status() != WL_CONNECTED) connectWifi();
if (millis() - lastRefresh >= REFRESH_INTERVAL_MS) {
if (WiFi.status() == WL_CONNECTED) fetchDepartures();
else strcpy(statusMessage, "Wi-Fi disconnected; retrying");
lastRefresh = millis();
drawScreen();
}
}“Deploy to device” opens this project in Schematik, where you can flash it to your board over USB.
Remix this project
Make it yours in one click
Open a full copy of this project in your own Schematik workspace — diagram, code, parts, and assembly steps included. Swap the sensor, add features, or redesign the whole thing with AI. The author's original stays untouched.