Train Station Clocks

The clocks in the space. See also Nottingham Hackspace's wiki:

https://wiki.nottinghack.org.uk/wiki/BigClocks

Hardware

The microcontroller is a Seeed Studio XIAO ESP32C3. For hardware details, schematic, and PCB layout, see the AEGMIS_GV60 repository.

Running the project

Prerequisites

• PlatformIO installed

Installation

Flash the server environment to the device:

$ pio run -t clean -t upload -e aegmis

To run on an SSD1306 OLED display instead, use the oled environment:

$ pio run -t clean -t upload -e oled

For wiring the OLED, connect it to the XIAO ESP32C3 as follows:

SSD1306	XIAO ESP32C3
VCC	3V3
GND	GND
SDA	D4
SCL	D5

Generation of compatible image data

$ ./icons/image2bytes.py ./icons/skull.gif

Setting the status of the display

Once flashed, the display will show its IP address. You can then control it via HTTP:

$ curl http://ip_address:port/ --data '{
  "text": "Repair cafe @\nSheffield Hackspace",
  "text_size": 1,
  "text_wrap": true,
  "flashing": false,
  "inverted": false,
  "horizontal_align": "left",
  "vertical_align": "top",
  "image": "ABgAAZmAAf+AGf+YH//4DgAwDv/wfH/+fv+uP/UEP1VU8VF39xV/MVX8PV/8cf++f/8eD/+wDgAwH//4Gf+YAf+AAZmAABgA",
  "image_width": 24,
  "image_height": 24
}'

Parameter	Type	Default	Description
text	string	""	The text to display. If too long, the display will scroll it.
text_size	integer	1	Text size multiplier, 1–5.
text_wrap	boolean	true	If true, overflow scrolls vertically; if false, horizontally.
flashing	boolean	false	If true, inverts colours every second producing a flashing animation.
inverted	boolean	false	Invert the colours of the display.
speed	integer	5	Scroll speed.
horizontal_align	string	"left"	"left", "center", "right".
vertical_align	string	"top"	"top", "middle", "bottom".
image	string	""	Base64-encoded image (output of the image2bytes script).
image_width	integer	0	Image width in pixels.
image_height	integer	0	Image height in pixels.

Integration tests

A test script is included that sends a series of curl requests and prompts you to verify each result visually:

$ chmod +x integration-test.sh && ./integration-test.sh 192.168.1.100

Included libraries

• Adafruit GFX Library - The base for our implementation
• AEGMIS_GV60 - Provides an Adafruit GFX compatible driver for the train sign display; based on the reverse engineering work of daniel1111 from the Nottingham Hackspace
• DotWidget - Provides a standard way of building a display widget for small IoT screens