“The Inky frame is a great choice with a sleek design and reliable performance, making it ideal for displaying information and images. However, due to its storage limitations, I found I needed to rely on fairly compressed JPEGs to get my own images onto it. While this can slightly affect image quality, the overall functionality and ease of use still make it a solid option for those who appreciate a clean and efficient display solution.
(Example is using a slightly modified version of the included NASA image of the day code)”
“This is an ideal device for a photo stand.
Thanks to the Inky Frame 4.0 and its excellent combination with the Pico W, anyone can easily create an ultra-low-power, battery-operated photo stand.
If you pre-process full-colour images using the JJN algorithm or similar techniques to reduce colours, you can achieve higher-quality image rendering compared to the standard matrix dithering process.
The 7.3-inch Inky Frame is great for its larger display, but the 4-inch version has a finer dot pitch, making images appear sharper and more refined.”
“This is an ideal device for use as a photo stand. I have created a programme with slideshow functionality using MicroPython, which I incorporate into my daily life.
There are a few important points to note when creating a slideshow photo application, which I will briefly outline here.
- Convert images to match the resolution of the Inky Frame (pre-processing). If the image has a different aspect ratio to the Inky Frame, adding a subtle drop shadow to the margins enhances the appearance (in my opinion).
- Full-colour images should be reduced to “7 colours” during pre-processing: black, white, green, blue, red, yellow, and orange, rather than the typical “8 colours” of RGB – black, blue, red, magenta, green, cyan, yellow, and white.
- For the error diffusion process during colour reduction in pre-processing, the “Jarvis Judice Ninke” algorithm produces better image quality than the Floyd-Steinberg algorithm built into PIL. However, since JJN is not included in PIL, performing this pre-processing in Python can be quite time-consuming. I recommend using a computer with high computational power for this task.
- Saving files as indexed-colour PNGs rather than JPEGs offers advantages in both file size and image quality (pre-processing).
- PNG images that have already been reduced to 7 colours (not 8) can be cleanly displayed by decoding them with “png.decode(mode=PNG_COPY)” and then running graphics.update(). This suppresses and avoids matrix dithering during execution in MicroPython.
- Careful selection of the microSD card is essential. The Inky Frame’s SD card library is sensitive to signal timing. In my experience, SanDisk 32GB and 64GB cards, including the one from the official accessory kit, work well. However, Transcend 32GB and 64GB cards were not compatible. And The “FAT32/MBR” format is a mandatory requirement.
- Searching and identifying the N-th image file by scanning the directory each time the device wakes up becomes inefficient when there are many image files. Instead, it is better to prepare a text file in advance (pre-processing) where each line contains a fixed-byte-size record of the image file path. In MicroPython, you can use "seek" to perform random access to the N-th line of this file and retrieve the corresponding path information. This method is far more efficient for obtaining image file paths. My photo stand has around 6,500 image files, yet it operates smoothly even with the limited memory resources of the PicoW running MicroPython. Whether accessing the first image, the last, or any file in between, the image loading process works at the same speed.
- When running on battery power, the device can be turned off using inky_frame.turn_off(), allowing it to operate for several months on standard batteries (depending on the frequency of image updates). However, writing to the microSD card with a low (depleted) battery can potentially corrupt the FAT file system. If you plan to save information such as the “current image number” to the microSD card for the next wake-up, it is advisable to include a voltage check before the write operation. If the battery voltage is low, avoid writing to the microSD card and instead display a message on the Inky Frame, including the measured voltage information, to make the situation clear.”
“Bought the Inky Frame + Accessories as a project to create a daily changing e-ink photo frame. Had some unexpected issues with the kit but the support team at Pimoroni were incredible and organised a replacement in no time. Can’t thank them enough for all of their help! Replacement Inky was simple to get working even as a relative newcomer to Raspberry Pi programming. I really appreciate all of the preloaded and online starter code that Pimoroni provides too.”
