I’ve been experimenting with a dichotomy of second screens for quite a long time at this rate. I've used a second phone-as-monitor, a laptop on the desk next to me, and, naturally, a "typical" secondary vertical monitor, which is the only one that's truly stuck. However, one that did stick was the XIAO 7.5-inch ePaper Panel over the couple of months, driven by a tiny XIAO ESP32-C3 running ESPHome, and it quietly became the most useful “monitor” on my desk.

To be clear, this isn't a second monitor in the traditional sense; it doesn't extend my PC's display, nor does it even connect directly to my PC. Instead, it's an always‑on activity and task tracker that sits next to my monitor and nudges me toward better focus. In a sense, it's better than a second monitor, because it minimizes distractions while keeping me on-task.

Why use ePaper?

A lot of reasons, really

I don't particularly have an issue with "regular" monitors in terms of eyestrain or discomfort, so I had initially shrugged off the idea that an ePaper display would be any kind of "upgrade" to keep on my desk. But while I didn't have those particular concerns when it came to picking up one of these, there are still a number of benefits. I can glance from my main screen to the ePaper display without any kind of glare or cognitive overload from bright, shiny colors. Eyestrain was never a concern of mine when it came to a monitor, but I'll be honest, I didn't really realize how much easier an ePaper display was to look at, either.

On top of that, the battery life is incredible. Not only did the battery last two or three days on a charge when I only updated the display if the data being shown actually changed, but I recently enabled the deep_sleep ESPHome component so that it runs every five minutes for 60 seconds at a time. While that may not seem like a lot, it's extended the battery life to four or five days. That's without tweaking it to account for when I go to sleep; for example, I could make it dynamically engage deep sleep, so that once my alarm is set, it doesn't disengage from deep sleep until a minute or two before I wake up.

I also love the minimalism of this particular setup and the physical presence that it maintains on my desk. It's grayscale and doesn't refresh often, and because it's a physical device that always sits on my desk, I can't just "minimize" the tasks that I need to complete, like I would on a secondary monitor. A second monitor is also always there, and because I'm used to it being there when I'm not working, I can overlook it. My ePaper display changes what's shown when all of my tasks are completed and my work calls are done for the day. In a way, I took complete control of the device to minimize my active control of it, and it greatly helps me.

To give you an idea of how valuable that is to me, I suffer from ADHD, and while I have found many coping mechanisms and made many quality of life improvements over the years to ensure that I keep on-task and focused, I'm nonetheless guilty of absentmindedly minimizing my task tracker on a second monitor on my PC. This has meant that what I was supposed to be doing was no longer in sight, and I'll get distracted, forget what I was doing, and have no visual indicator to keep me going. I physically can't do that with an e-ink display like this. It shows me the data on the screen that I'd normally keep on my second monitor anyway, but without a way for it to disappear and then lose track of what I was doing.

The perfect combination of hardware and software

ESPHome made it easy

The XIAO 7.5-inch ePaper Display is big enough to show me exactly what I need without feeling cramped; any smaller and I wouldn't be able to fit everything on it, and any larger and it would take up too much space and be a hindrance rather than a help. The XIAO ESP32-C3 comes with it, and while it's a noticeably weaker chip compared to the ESP32-S3 that you'll find in the TRMNL DIY kit, it more than gets the job done. The only difficulty is if you try to display images due to the lack of PSRAM, so avoid that if at all possible.

For power, it packs a 2,000 mAh battery that can be charged by plugging a USB-C cable into the ESP32. You won't get battery percentage details or anything without adding additional hardware to it, but you'll get a feel for how long it'll last after you've used it a few times. Just check if the ESP32 is emitting a red LED; it'll shine through the USB-C port if it's switched on. Finally, I've paired mine with a presence sensor that's mounted on a chest of drawers beside my desk. The condition for updating the display at present uses this as a check to see if it needs to be updated; if no motion has been detected in the last five minutes, it doesn't update the display when it wakes up from deep sleep.

I've covered ESPHome a lot in the past, but it's seriously one of the best ways to develop on any ESP32-based board. It links up with Home Assistant to pull data, and I pull data into Home Assistant from Google Calendar, Asana, and Pirate Weather. I then create template functions specifically for processing this data in a way that can be easily retrieved and rendered by the display, and a flag is updated to say when new data has been retrieved, so the screen knows to update.

If you're interested in seeing my code for this, I've shared it on GitHub, so you can modify and tune it to your needs. I have an instant view of the weather and the chance for rain, I have my living room temperature, all of my tasks, and the time of my next call. It's perfect, and it helps keep me focused and organized.

It's not a second monitor in the traditional sense

But it can be

I know what you're probably thinking: "That isn't actually a second monitor," but the thing is, why isn't it? I can pull data from my PC using HASS.Agent, and I can display data on the screen that I would normally put on my second monitor, too. For all intents and purposes, it is a monitor, as it checks all of the boxes for what I used a second monitor for.

Think of it like this: any data in Home Assistant can be shown on the display, and that data can be anything you can import to Home Assistant. You can pull your PC's screen if you want, and you can pull data from countless sources; really, you can do practically anything with it if you just put in the time to make it work. All you need to do after that is wire it up to your ePaper display for rendering, and you're done.

This has been one of the best investments I've made in a long time. It's exactly what I needed, except I didn't even know it was what I needed before I got it. I wanted something fun to play around with and learned, and ended up accidentally making the best productivity tool and secondary monitor I could have asked for in my office.