excess.org

Ian Ward

Software
CKAN contributor/tech lead
Urwid author
PyRF contributor
Speedometer author

Presentations
Contributing to Open Source
IASA E-Summit, 2014-05-16
Urwid Applications
2012-11-14
Urwid Intro
2012-01-22
Unfortunate Python
2011-12-19
Django 1.1
2009-05-16

Writing
Moving to Python 3
2011-02-17
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Urwid on a Crystalfontz 635 LCD

Crystalfontz preview
Posted on 2010-03-14.

The development version of Urwid now has support for display and input on a Crystalfontz 635 LCD panel. These are small LCD screens that fit in a PC's 5ΒΌ" drive bay. They have six buttons, four red/green LEDs and a 20x4 character display with an adjustable backlight.

This sort of device is great for simple interfaces to headless machines, like media PCs and special-purpose systems. Urwid simplifies building an interface by taking care of text wrapping, scrolling and cursor movement. The new lcd_display.py module also handles CRCs, acknowledgements and can simulate key repeating so the device acts more like a regular keyboard. It should also be easy to add support for other similar devices.

The new example program lcd_cf635.py demonstrates the new display module and all of the features of this device. It also provides a good example of how to build simple menus and customize widgets for a device like this.

lcd_cf635.py demo program

Tags: Urwid Hardware Software Linux Python