Skip to content
master
Switch branches/tags
Go to file
Code

Latest commit

 

Git stats

Files

Permalink
Failed to load latest commit information.
Type
Name
Latest commit message
Commit time
img
 
 
lib
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Overview

This library is an improvement and extension of this repository. It is meant to work under Python3+ for the Raspberry Pi's GPIO output.

The API into this library is very similar to its predecessor and the provided examples there may be easily ported.

For more information about this display, see the waveshare site. There is also a product wiki page.

It requires the GPIO library that is typically available on the Raspberry PI. The example programs require some packages for the QR code rendering and Twisted event loops.

The example programs are centered around displaying Lightning Network BOLT11 invoices in QR Codes that can be picked up by a mobile wallet to perform a payment.

In The Wild

This was developed for a Lightning Network Jukebox demo project. You can see a demo of this here: Lightning Network Jukebox at the Bitcoin Rodeo

Also, the source code for that project is in this repository.

The Code

There is a bunch of stuff in the repo, but the featured general-purpose module is in [waveshare/epaper.py]. This module provides the Python 3 API for driving the display for an application.

Wiring

This diagram is for the Pi 3, and Pi 2. This will probably work on other Raspberry Pi iterations, but double-check that the pinout is the same to be sure. This site has a clearer visual reference for finding the pins.

PI3 Pin E-Ink Pin
3.3 v 1 6 3.3v
GND 6 5 GND
GPIO15 10 4 DOUT
GPIO14 8 3 DIN
GPIO04 7 2 WAKE_UP
GPIO02 3 1 RESET

Configuring Pi Hardware

You will need to edit /boot/cmdline.txt and delete the parameter console=serial0,115200 from the line.

Also, you will need to enable the UART interface. Edit /boot/config.txt and add the line enable_uart=1 and reboot.

If you are running with a Raspberry Pi 3, the UART port conflicts with the bluetooth connection and you will need to disable bluetooth for this to work. Edit /boot/config.txt and add dtoverlay=pi3-disable-bt and reboot.

Configuring Pi Software

The libpython-dev and RPIO libraries are needed.

sudo apt-get update
sudo apt-get install libpython-dev python3-rpi.gpio

The pyserial package is also needed via pip3

sudo apt-get install python3-pip
pip3 install -U pyserial

For the QR Code examples, qrcode and pillow will need to be installed to render the image to be displayed.

sudo apt-get install libopenjp2-7 libtiff5
pip3 install -U pillow
pip3 install -U qrcode

For the Twisted event loop examples, twisted will need to be installed.

pip3 install -U twisted

Examples

test_basic.py This draws some basic text and shapes on the screen in different greyscale colors. Intended as a basic smoke test for the libary and doesn't depend on the QR Code and twisted libraries.

test_basic.py

test_qr.py This doesn't draw anything on the e-ink screen, it just tests that the QR code dependency is working properly. It outputs a rendered QR Code as ascii and the coordinate draw instructions on the terminal.

(you can pipe the standard of the script into less like so: ./test_qr.py | less to avoid scrolling by too fast)

test_qr.py

test_cycle.py This cycles through several LN Invoice QR Code draws on the e-ink display. It measures the time of the various phases and outputs that on the console for comparison.

test_cycle.py

test_gpio_input.py This has nothing to do with the e-ink, but just does some basic GPIO push button input. For making sure that works beforecombining htat with the Twisted and e-ink parts.

test_io.py This also has nothing to do with the e-ink, but just does some basic GPIO push button input and LED output for making sure that works before combining that with the Twisted and e-ink parts.

test_twisted_io.py This is an example of using the e-ink display and the GPIO input and output from a Twisted event loop. The example program displayes the QR code corresponding to a push-button input.

About

A library for interfacing with the 4.3inch UART e-Paper from a Raspberry Pi 2/3 via Python3 with example programs to display QR Codes for the Lightning Network

Resources

License

Releases

No releases published

Packages

No packages published

Languages