I've tried all kinds of ESP32-powered displays at this point, from ones that can function as a voice assistant to tiny displays I can mount on my NAS. However, the one that started it all was arguably the XIAO 7.5-inch ePaper Panel, a cost effective ESP32-based display that you can program to your heart's content. However, it's admittedly quite barebones, and that's where the reTerminal E1002 comes in.

The reTerminal E1002 from Seeed Studio is quite similar on the surface to the aforementioned display: after all, it's ePaper, it has a battery, and it's ESP32-based... but that's where the similarties end. It's a full-color alternative (well, six-color, but more on that later), packing eight additional GPIO pins, three separate buttons, a temperature and humidity sensor, and even support for a micro SD card. All while fully encased in metal.

It's a wonderful device that feels like an end-game of sorts when it comes to ESP32-based ePaper displays. While we'll be focusing on the E1002, the company also sent us the monochrome E1001 for testing, which has a slightly bigger screen (7.5-inches versus 7.3-inches) and can't display color. Everything else is the exact same, and most of the observations made in this article, unless otherwise stated, will apply to that panel, too.

Both of these displays will set you back $79 and $109 respectively, though both are available at an early bird pricing that knocks $10 off of the asking price. As well, Seeed Studio provided a 5% off discount code, P8419HDJ, that you can use at checkout. This code does not yield any affiliate revenue for us, and is provided for the benefit of XDA's readers.

About this article: Seeed Studio provided us the reTerminal E1001 and E1002 for the purposes of this article. The company had no input into its contents.

Solid hardware across the board

It's extremely well-built

We'll start off with hardware before going over the software that you can run, and we'll go with the primary difference first: the screen. From what I can tell, these are the two screens currently in use:

• reTerminal E1001: GooDisplay GDEY075T7 panel
  • Panel chip: UltraChip 8179
• reTerminal E1002: GooDisplay GDEP073E01(E6) panel
  • Panel chip: Not connected

The reTerminal E1001 screen feels like an exact one-to-one copy of the XIAO 7.5-inch ePaper Panel screen, though that's not a bad thing. It supports partial refresh, has an 800x480 resolution, and more than does the job for practically anything you'd ever need it for. The reTerminal E1001 isn't much more expensive at full price than the previously-mentioned XIAO screen, and for the added features, the extra $10 is extremely worth it for the better build quality, battery monitoring, and more.

The reTerminal E1002 screen is quite interesting. It undoubtedly looks really good, and while also being an 800x480 resolution screen, images look wonderful on it. The colours are nice and vibrant, and the Spectra 6 technology in use allows for 85% coverage of the NTSC color palette. Its marketed as "six colors", but to be clear, this means that there are six pigment colors in use: black, white, red, yellow, green, blue. By mixing pigment positions and controlling reflectivity or transparency at the subpixel level, they can be blended to show up to 4,096 colors. That gives this panel a 12-bit color depth. Combined with the anti-glare coating, it looks pretty good, though it can be harder to see in a dark room than the reTerminal E1001.

There are a couple of downsides to that color capability though, and one is the time it takes to refresh the screen. Unlike the monochrome panel in the E1001, a full-color panel takes considerably longer to refresh. To display a target color on the E1002, the controller has to send carefully timed voltage waveforms that push some pigments forward and pull others back, and moving too quickly can result in pixels being put in the wrong place. You can't partially refresh the screen either, so each screen change can take up to 15 seconds to complete.

The second downside is the potential for ghosting. Seeed Studio recommends not leaving an image on the screen for longer than a day, and refreshing it frequently while building software and testing the screen can also damage it if done for a long period of time. It's quite delicate in that sense, so if you do pick up one of these, be mindful of the screen's longevity.

When it comes to the other hardware, everything else is the same across both models. You get an SHT40 temperature and humidity sensor, a buzzer, three buttons, an on-board LED, a real-time clock (no cell battery included), and a microphone. The microphone is particularly interesting, as Seeed does not provide any tutorials on how to use it, but it's in the official specifications table and in the reTerminal E1002 datasheet. Its power is controlled by IO38, its CLK by IO42, and its data is output on IO41.

Finally, it uses a Winbond W25Q256JV for flash storage, which is a 256 Mbit serial NOR flash, or 32 MB of flash storage. It uses SPI/QSPI and supports x1, x2, and x4, and the ESP32-S3 supports execute-in-place (XIP) and asset storage on this particular model.

That's it for the hardware, and it's a pretty great package all things considered. The metal chassis has a hole in the back you can use to hang up the reTerminal, and it also comes with a 3D printed plastic nub that you can screw into the back if you'd prefer to use it standing up on a desk.

When it comes to software, it's still a DIY product

SenseCraft HMI is currently in beta

Seeed Studio has always marketed these devices as DIY-style devices, with support for ESPHome, TRMNL, and Arduino, but there's a new platform supported too: SenseCraft HMI. This is a Seeed Studio-made interface design platform in the cloud, and while it has some good ideas, it's not really ready for general usage just yet. It's in beta currently, and it's missing many features it useful.

Despite the features it lacks, the beta version shows that it has a lot of potential. Right now, it can show a webpage, an RSS feed, or a live weather dashboard. It can also display a gallery of images, and you can make a canvas with your own layout.

Unfortunately, designing your own layout isn't particularly useful just yet, as even though the SenseCraft HMI site says "Supports multiple data interfaces such as MQTT and REST API," no such features are actually implemented as of yet. Data is shown in a static form only. Even trying to connect to my local Home Assistant instance and display the dashboard using Puppet failed to work.

My favorite feature by far, though, is the AI-generated canvas, which allows you to ask a language model inside of SenseCraft HMI to design your layout for you. You specify what you need, where you want it, and the model will provide you a layout that you can tweak and modify before deploying it. When MQTT and REST support is added, I can see this being an incredibly useful feature, and even what it's capable of currently is quite powerful. It's not there in terms of features just yet, but I think it will be one of the best ways to build a display like this once it gets there.

ESPHome is finicky for the E1002

As I tend to do, I elected to move over to ESPHome, which works but isn't completely painless. In the documentation for the E1002, Seeed Studio provides an external_component to load, but the problem is that the external_component is broken on GitHub. We can see that by looking at the affected code, where most of the lines between line 177 and 185 are missing a semi-colon.

To get around this, you'll need the following external_component instead, which uses the same code but with a pull request merged that fixes the problem:

external_components:
 - source: github://lublak/esphome@pull/1/head
 components: [waveshare_epaper]
 refresh: 1h

As well, keep in mind that the provided code samples will work, but the advanced example that aims to utilize most of the sensors doesn't actually use the on-board PSRAM out of the box. To fix this, do the following:

esphome:
 name: reterminal-e1002
 friendly_name: reTerminal E1002
 platformio_options:
 build_flags: "-DBOARD_HAS_PSRAM"
 board_build.arduino.memory_type: qio_opi
 on_boot:
 priority: 600
 then:
 - output.turn_on: bsp_sd_enable
 - output.turn_on: bsp_battery_enable
 - delay: 200ms
 - component.update: battery_voltage
 - component.update: battery_level

esp32:
 board: esp32-s3-devkitc-1
 framework:
 type: arduino

psram:
 mode: octal
 speed: 80MHz

These will enable PSRAM support in ESPHome so that it can use the 8MB on-board. The framework type has to be Arduino (as opposed to the default esp-idf) as well, or else it won't compile.

With this configuration, I was able to build a basic temperature and humidity display (which pulls from the on-board SHT40) and a now-playing display that simply pulls from my Home Assistant dashboard using Puppet. It's not perfect, but to be honest, I could probably improve it significantly if I spent more time optimizing the pulling and displaying of the image.

Overall, after these tweaks, I'm very happy with what I could do with the reTerminal E1002. I even got the microphone to initialize with the following code:

i2s_audio:
 - id: i2s0
 i2s_bclk_pin: GPIO42
 i2s_lrclk_pin: GPIO2 # dummy pin

switch:
 - platform: gpio
 id: mic_power
 pin: GPIO38
 restore_mode: ALWAYS_ON

microphone:
 - platform: i2s_audio
 id: pdm_mic
 adc_type: external
 i2s_audio_id: i2s0
 i2s_din_pin: GPIO41
 pdm: true
 sample_rate: 16000
 channel: left

I didn't test the actual quality of the microphone, and I was merely curious if I could get it to initialize. There may be more work required to get usable audio from it.

All in all, the reTerminal E1002 is a pretty powerful display, and if you had ideas for what you would use another ESP32-powered ePaper display for, think of all of that and more with this particular device. Thanks to the GPIO support, too, you could theroetically add your own functionality. For example, you could try tacking on a speaker and turning it into a voice assistant, or even a media player.

I love both of these displays

It's the end-game of ePaper

If you're looking to get an ESP32-based ePaper display, then honestly, this is the end-game of what that will look like. The E1001 is everything that made the XIAO 7.5-inch ePaper Panel good but with even more built on top of it, and the E1002 with its full color display is a beast of its own. Once SenseCraft HMI is capable of linking up all of your services and can read data from MQTT and API endpoints, this'll be the product for just about everyone.

If you're looking for a productivity buddy for your desk, I can't recommend either of these enough. These are genuinely a pair of fantastic displays, and no matter which you go for, they'll both be excellent. Even being able to take it and hang it on your wall with ease is a fantastic detail, and the inclusion of the 3D printed plastic connector to stand it upright is a nice touch. The documentation for ESPHome needs a little bit of work, but nothing most developers who have used ESPHome wouldn't be able to figure out.

The XIAO 7.5-inch ePaper Panel was one of the best additions I ever made to my desk, and I'll likely now be replacing it with the E1001 thanks to the additional features that it has. As for the E1002, there are a lot of fun ways to make that one work, and I'm not fully decided on where I'll set it up just yet and for what purpose. One thing is for sure, though: the E1001 arguably makes the XIAO obsolete, and the E1002 is all of that and then some.