[HN Gopher] Show HN: I made my own TRMNL e-ink device
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Show HN: I made my own TRMNL e-ink device
Author : stavros
Score : 47 points
Date : 2025-04-24 11:34 UTC (11 hours ago)
(HTM) web link (www.stavros.io)
(TXT) w3m dump (www.stavros.io)
| estsauver wrote:
| This is neat--what's the typical refresh rate/update speed for
| the image service?
|
| Is the API is basically "Push PNG to server, PNG displays on
| whiteboard?"
| stavros wrote:
| No, TRMNL generate the images themselves. The device requests
| the image every so often (with an interval configurable by the
| server). They've (understandably) built the firmware to be
| pretty specific to their service, though you can build your own
| server for it as well (it's just a JSON response with the image
| to fetch).
| joshstrange wrote:
| The API is:
|
| You write HTML templates (that are stored on their servers)
| then can post data to them (or have them poll an endpoint to
| get the data) to "merge" into the template.
|
| Think: <h1>Hi {{ username }}</h1>
| <div>You have {{ openPRCount }} open PRs</div>
|
| And you need to provide (via push or pull):
| {"username": "joshstrange", "openPRCount": 10}
|
| That might not be the exact syntax (I wrote my custom plugin a
| month or two ago and haven't touched it since).
|
| They provide a "UI Library" (Design System) [0] to give you
| building blocks of UI to use if you want.
|
| It made it really easy to get started. They limit to 1 screen
| update every 15min (that is the fastest you can have the screen
| update). But you can press the restart button on the back of
| the device to force it to update, you might need to force your
| plugin to re-generate the image before you do that.
|
| If you want to flash your own firmware you can lower that (at
| the expense of battery life) value or even have it call out to
| your own server that can do whatever you want.
|
| [0] https://usetrmnl.com/framework
| JKCalhoun wrote:
| TRMNL's site seems to think there is _not_ a cost-savings to
| build-your-own. They don 't appear to include the licensing cost
| though. From their site:
|
| > Making your own TRMNL from scratch is not an economically
| rational decision, but rather a labor of love. Our own team
| learned this the hard fun way while building v1 over 7 months,
| from Dec 2023 to July 2024.
|
| > Here's what you can expect to spend per component:
|
| > * Battery, $5 (unnecessary if you prefer plugged in)
|
| > * EPD screen, $65 (see the Waveshare 7.5" on Amazon)
|
| > * Microcontroller, $3-50 (depends if you build/solder yourself
| or leverage a PCB prototyper)
|
| > * Enclosure/case, $3-20 (design + 3D print yourself or use a
| print farm)
| stavros wrote:
| Yeah, my BOM was $20 for the driver and $50 for the screen,
| plus $50 for the TRMNL license. About the same as the TRMNL I
| bought, in the end, though as you say the license is a big part
| of it.
|
| My worry is about my lifetime license eventually turning into a
| subscription requirement.
| n8cpdx wrote:
| > I could have my own TRMNL for under $80, or, if you factor in
| my time, around $5,000, which is a bargain
|
| I love the self awareness.
|
| I'm trying to be better about factoring in my time, largely
| unsuccessfully.
|
| E.g. I just spent $200 of my time trying to trade in an iphone at
| the apple store (the Apple Store sucks now and has terrible
| processes). Value of trade in: $200
| stavros wrote:
| The trick is that, if you're enjoying the process, the cost is
| negative! Trading in an iPhone doesn't sound very enjoyable,
| but to each their own.
| drcongo wrote:
| stavros is one of my favourite posters on HN, and the writing
| on his site is full of beautiful turns of phrase like that.
|
| > The Timeframe is a beautiful, battery-powered, high-
| resolution e-ink device that sits on my desk and reminds me of
| the inexorable grind that saps my creativity and drains me of
| the will to live.
|
| From https://www.stavros.io/posts/making-the-timeframe/
|
| edit: Ever since I read the Timeframe article I've been itching
| to do the same thing myself, but I suck at these things so
| worry that I'm just going to end up with more piles of
| electronic parts in my cupboard of broken dreams.
| billev2k wrote:
| Speaking of a beautiful turn of phrase: "...more piles of
| electronic parts in my cupboard of broken dreams."
|
| :)
| stavros wrote:
| I call it the "cupboard of infinite possibilities".
| stavros wrote:
| Email me and I'll help you!
| sho_hn wrote:
| Have mine in the hopes of making your itch unbearable:
| https://imgur.com/a/diy-automatic-e-ink-newspaper-using-
| rust...
|
| You can do it! :-) Also happy to help if you have questions.
| stavros wrote:
| Oh I had seen yours! What a fantastic project, well done.
| Beautiful result.
| sho_hn wrote:
| Thanks!
|
| I'm currently making something inspired by your
| Timeframe, but using an OLED panel, as a 2nd screen for
| my desk - but almost the same form-factor and a similar
| design.
|
| I'm trying out a faux 3D-printed wood process with wood
| powder-infused PLA, sanding and staining, and a faux wood
| grain I baked into the geometry using a displacement map,
| though. Hoping to make it all posh.
| stavros wrote:
| That sounds fantastic! I'd love to see updates, we have a
| maker Discord server I can invite you, if you're
| interested, or it would be fun to just email! My email is
| in my profile.
| KMnO4 wrote:
| How did you come to the $200 figure?
|
| Your time does have value, but it's in terms of opportunity
| cost, not hourly wage. Presumably you wouldn't have made $200
| had you not gone to the Apple Store (unless you went when you
| were supposed to be working and have a job where that time
| becomes unpaid).
| stavros wrote:
| Not the OP, but I just figure that I could be contracting
| somewhere at any point, really, so each hour costs me my fee.
| joshstrange wrote:
| > $20 "developer edition" license which "unlocks their API". I
| expected this upgrade to give me API access so I could retrieve
| the image that's displayed of my device, but that's not actually
| the case, and you need a $50 "virtual device" license for that.
|
| I cannot find a mention of the developer edition. I own a TRMNL
| and use the api for free (I assume because I have a device) and
| then they offer a lifetime $50 license to use their backend with
| your own device. I think that's fair.
|
| Also, I don't quite understand their back ordering information. I
| ordered mine and got it less than a week later even though they
| said it was back ordered.
| stavros wrote:
| That option is for when you add it to your cart. You get API
| access with the device because you have one, but AFAIK you
| can't develop plugin without the dev option? I don't know, I'm
| confused :(
| joshstrange wrote:
| Interesting, I have developed plugins for my TRMNL and I only
| paid for the device.
|
| Or at least I've developed HTML-based views that are custom
| (I think that's "plugins") that are displaying on my device.
| stavros wrote:
| Hm :/ I wonder why I paid the extra $20, then...
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