davweb / inkplate10-poc

A proof of concept to get a selected set of the features of the Inkplate 10 working.

inkplate10-poc

This is a proof of concept to get a selected set of the features of the Inkplate 10 working. The aim was for me to focus on getting the features of the hardware and software stack working before worrying about a real project.

This is my first time writing C/C++ and my first time working with hardware like this so don't assume any of this code is best practice or optimal. Feedback is welcome!

Features

The working features are:

• Wi-Fi
  • Static IP Address (to keep wake time to a minimum)
• Custom Fonts
• Partial Display Updates
• Lower Power Mode
  • Waking Up Using Button
• Real Time Clock
• Writing to Files
• Logging
• HTTP Requests
• JSON Parsing
• Development and Production Builds

The excluded features are:

• Touchscreen
• Bluetooth
• Two-Way Serial Communication
• HTTPS Requests
  • My follow on project will use a local server to reduce the number of network requests the Inkplate has to made, so HTTPS won't be needed.
• Debugging
  • As far as I can tell debugging for the Inkplate is limited to serial messages due to the version of the ESP32 used. The ESP32-S2 and ESP32-S3 have a built in JTAG interface but the ESP32-D0WD-V3 used by my Inkplate 10 does not.
• Detect when charging
  • This is not possible with the Inkplate hardware.
• Updated Partition Map
  • I have not needed this yet.
• Tests
  • They seem unnecessary when the Inkplate is mostly just displaying things
• Storing WiFi credentials in flash
  • The esp_wifi_set_storage API call looks interesting but not worth writing a whole WiFi client for.

Build Flags

The project has the following build flags.

Flag	Description
BATTERY_LOG_FILE	A CSV file to record battery voltages to.

Wireless Network Configuration

The WirelessConfig.h should be updated to set your WiFi configuration.

Macro	Description
WIFI_SSID	The SSID of a Wi-Fi network to connect to.
WIFI_PASSWORD	The Password of a Wi-Fi network to connect to.
WIFI_IP_ADDRESS	An IP address to use if not using DHCP
WIFI_GATEWAY	The gateway to use if not using DHCP.
WIFI_SUBNET	The subnet mask to use if not using DHCP.
WIFI_DNS1	The first DNS server to use if not using DHCP.
WIFI_DNS1	The second DNS server to use if not using DHCP.

Building fontconvert

The build requires the fontconvert binary to be on the PATH.

Here are instructions on how to build it on macOS:

1. Install gcc and freetype library using Homebrew.

   brew install gcc freetype
   

2. Put the Homebrew gcc on the PATH ahead of the Apple one:

   sudo ln -s $(which gcc-13) /usr/local/bin/gcc
   

3. Checkout the Adafruit GFX Library.

   git clone https://github.com/adafruit/Adafruit-GFX-Library.git
   

4. Edit fontconvert/Makefile and change:

   CFLAGS = -Wall -I/usr/local/include/freetype2 -I/usr/include/freetype2 -I/usr/include
   LIBS   = -lfreetype
   

   to:

   CFLAGS = -Wall -I/opt/homebrew/include/freetype2
   LIBS   = /opt/homebrew/lib/libfreetype.dylib
   

5. Build the binary.

   cd Adafruit-GFX-Library/fontconvert
   make
   

Downloading fonts

If you have certificate errors when convert_fonts.py tries to download the source font files either set platformio-ide.useBuiltinPython to false or run the script outside of the PlatformIO build chain once to download the files.

References

• Inkplate Documentation
• ESP-IDF Programming Guide
• SolderedElectronics/Inkplate-Arduino-library on GitHub
• Platform IO Documentation