LOBBY
Hardware· 7 min read

Using a TRMNL as a Meeting Room Display: What Works, What Doesn't, and What It Costs

TRMNL is open-source e-ink hardware, and one of several panels that work as a meeting room display. Here is what TRMNL is, what it can and cannot do as a room display, the realistic cost, and how it now compares to the cheaper alternatives.

Most posts about meeting room displays start with the software. We are going to start with the hardware, because that is where most of the cost and complexity live.

TRMNL is an open-source, battery-powered, 7.5 inch e-ink display. It is one of the panels Lobby runs on. It is also, on its own, one of the more interesting pieces of office signage hardware to land in the last few years, and almost no one outside of niche maker communities is talking about it. This post is the honest tour.

What TRMNL is, in 60 seconds

TRMNL is a small e-ink dashboard built around an ESP32-C3 board, a 7.5 inch 800 by 480 monochrome e-paper screen, and an 1800 mAh battery, upgradeable to 2500 mAh. It runs open-source firmware (the source is on GitHub at github.com/usetrmnl) and connects to WiFi to fetch screen images from whatever server you point it at. A finished TRMNL OG is USD 139 direct from the TRMNL shop for 1 to 9 units, and volume pricing slides to USD 99 per device at 151 units and above. There is also a USD 47.99 DIY kit through Seeed Studio if you want to assemble one yourself.

The screen consumes effectively zero power between refreshes, which is what gets you months of battery life rather than hours — something no LCD-based competitor can touch.

Why this matters for meeting rooms

Most proprietary meeting room displays are built on a similar idea (e-ink, low power, WiFi sync). Joan was the first at real scale. The difference is scope. Joan and Robin sell hardware that runs their own platform. A Joan 6 runs Joan. It does not run Robin, a Lobby image, or a Home Assistant dashboard at the weekend. For plenty of buyers that is the right trade: one vendor, one support contract, and in Joan's case a platform that also covers desk booking, visitor management and digital signage. It matters only if you want to change the software later without changing the hardware.

TRMNL takes the other approach. You buy the hardware once and choose what runs on it. For a meeting room display, that means:

  • Lobby today, something else tomorrow if you change your mind.
  • Self-hosted firmware updates if your security team requires them.
  • Repurposing the display as a quiet office sign, a weather panel, or a status board outside business hours.
  • The physical device is not tied to a single software vendor.

If the software layer is the part you are still choosing, our guide to meeting room display software lays out the options.

What TRMNL does well as a room display

The things that make TRMNL a strong room display are mostly things you would expect from any e-ink panel, plus a few that are particular to this device.

  • Battery life. 3 to 6 months on a single charge in typical office use, depending on refresh frequency.
  • Readability. 800 by 480 monochrome e-ink is readable from about 5 metres at door height. No glare. No backlight to compete with overhead lights.
  • Silent. No fan, no hum, no light.
  • Light. At 120 g it is the lightest panel in this class, which makes adhesive mounting genuinely easy.
  • Simple setup. Lobby installs from the TRMNL plugin store. There is no firmware to flash, which is one step fewer than most alternatives.
  • Quiet WiFi behaviour. The device wakes, syncs, sleeps. It does not chatter on the network. The IT security team likes this.

What TRMNL does not do

An honest list, because this hardware is good but not magic.

  • Touch. The 7.5 inch panel is not touch. If you want a "tap to check in" interaction at the display, you need either a paired QR code that opens a check-in page on a phone, or a separate tap accessory. Lobby uses the QR approach because it works in every office and needs no extra hardware.
  • Fast refresh. E-ink updates take a second or two. For a room display this is fine. For an interactive UI it would not be.
  • Colour. Monochrome. You get black, white, and a few greys.
  • PoE. No power over Ethernet. The device runs on battery, with USB-C charging.
  • Native MDM. If your organisation requires Jamf or Intune control of every endpoint, TRMNL does not enrol. You control it through firmware configuration and WiFi credentials.

The realistic cost per room

For a single meeting room, with the platform that runs on top.

  • Hardware. USD 139 per display for 1 to 9 units, one-off, bought direct from shop.trmnl.com. Volume pricing slides to USD 99 per device at 151 units and above. Lobby takes no markup on the hardware. The Seeed Studio DIY kit is USD 47.99 if you assemble it yourself. You can also run Lobby on a tablet, TV or monitor you already own, at no hardware cost.
  • Mount. A desk stand is included. The official wall mount and aftermarket magnetic plates are sold separately.
  • Software (Lobby). Free forever for up to 3 active displays, all features included, no credit card. Beyond that, Unlimited is USD 30 per month billed yearly (USD 360 a year); the monthly list price is USD 50. Pro Unlimited is USD 60 per month billed yearly. Billing is monthly or yearly, cancel any time, no annual contract. All listed on our pricing page.
  • Setup time. Around 10 minutes per display for the WiFi pairing, then a couple of minutes per room to connect calendars.

For comparison, in Joan's EUR price zone a Joan 6 RE lists at EUR 349 excluding tax and Joan's platform starts at EUR 49 per month for the base plan, with additional device licences at EUR 9.99 per device per month on annual billing (EUR 12.99 monthly). In Joan's USD zone the same products are USD 399 and USD 51, with device licences at USD 10.99 (USD 12.99 monthly). Joan's pricing page geolocates by IP and serves EUR, USD, GBP or AED with no manual selector, so what you see may differ from what is quoted here. On those figures, a 10-room office running e-ink plus Lobby lands at roughly a quarter to a third of the five-year total. Joan's plan also covers desk booking, visitor management and signage, which Lobby does not, so the two are not like for like. The numbers move with plan tier, currency and discounting, so treat this as an order of magnitude rather than a quote. The pricing comparison post goes through the worked example.

How TRMNL compares to the Seeed reTerminal E1001

Since we first wrote this, a second panel arrived that runs the same firmware and does the same job for about half the money. It is worth putting the two side by side honestly, because we have changed our own recommendation.

The Seeed reTerminal E1001 is a 7.5 inch monochrome e-paper display driving the same 800 by 480 panel. The differences that matter:

  • Price. USD 69 against USD 139, and USD 62.99 against USD 119 at ten or more units.
  • Case. Metal against TRMNL's polycarbonate and ABS.
  • Silicon. ESP32-S3 with 8 MB PSRAM against TRMNL's ESP32-C3 with 400 KB of RAM.
  • Battery. 2000 mAh as standard against 1800 mAh, though TRMNL sells a 2500 mAh upgrade.
  • Certifications. The Seeed adds TELEC PSE and UKCA to the FCC, CE and RoHS marks both carry.

Two things TRMNL wins, and they are real. It is lighter — 120 g against 218 g — which matters if you are mounting with adhesive rather than a screw. And it is simpler to set up: Lobby installs from TRMNL's plugin store, where the Seeed needs about two minutes of one-time firmware flashing per device first. Easy, but it is a step, and at twenty rooms it is forty minutes you would not otherwise spend.

Neither is worth paying double for, which is why we now recommend the Seeed by default. TRMNL still works with Lobby, it is still supported, and if you already own TRMNL devices there is no reason to replace them.

The "can I just run my own software on it" question

Yes. TRMNL is BYOD-firmware. If you have an internal team that wants to render dashboards or signage with your own server, you can. The firmware accepts a target URL and refresh interval. The display polls that URL on its schedule and renders whatever PNG comes back. That is the whole protocol. Self-hosting needs no licence.

This is also why Lobby works on it. Lobby's job is to take your Google Calendar or M365 room calendar, render a clean status image, and serve it to the display on schedule. Nothing exotic. The device does not know it is in a meeting room. It just renders the image.

Three things we wish we had known earlier

  1. Pick the finished device if you are doing more than two rooms. The DIY kit is fun, but assembly takes about 20 minutes per device and the cost difference for ten rooms is not worth the soldering iron.
  2. Place it at eye level, not head height. Slightly below eye level reads better when you walk up to the door. The mount allows for it.
  3. Use a longer refresh interval on quiet days. The default fifteen-minute refresh is fine in busy offices. For a small office with five rooms, twenty or thirty minutes will meaningfully extend battery life without anyone noticing the lag.

Who should not use TRMNL

If any of these are true, TRMNL is not your best option.

  • You need full Jamf or Intune device management, with screen capture and remote wipe.
  • You want a 13 inch display for very long room names or rich content.
  • You want colour.
  • You need PoE because WiFi is unavailable in the meeting room corridor.
  • You want one platform that also handles desk booking, parking and visitor management.
  • You are buying at volume and the price difference against a comparable panel matters more than the slightly simpler setup.

For everyone else, it is capable e-ink signage hardware that does the job well.

Put Lobby on your e-ink display

Lobby is the software layer that turns an e-ink panel into a room display. It reads your Google Workspace or Microsoft 365 room calendars, renders the room status as a monochrome image, and serves it to the device on the refresh schedule you set. Setup takes minutes per room: pair the display to WiFi, connect the calendar, mount it by the door. Read about Lobby's hardware options, compare the panels side by side, or get started with Lobby.

TL;DR

TRMNL is open-source e-ink hardware that makes a good meeting room display. It is 7.5 inches, monochrome, battery-powered (3 to 6 months per charge), and costs USD 139 per display at 1 to 9 units. No touch, no colour, no PoE, and no MDM. It is the lightest panel in its class and the simplest to set up.

The Seeed reTerminal E1001 now does the same job for about half the price, in a metal case, on faster silicon — which is why we recommend it by default. TRMNL remains supported. Pair either with Lobby (free forever for up to 3 displays, then USD 30 per month billed yearly for unlimited displays) to get a complete room display setup for materially less over five years than a single-vendor stack. The fact that the hardware is not tied to one software vendor is the main reason we build on panels like these.

Related reading

Sources

Software prices verified 19 August 2026. Hardware prices and Joan figures re-checked 29 August 2026. Vendor pricing changes and varies by region — confirm directly with each vendor.

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