TRMNL needs a KM plug-in

Hopefully this post doesn't trigger any spam filters. It's a request for a KM plug-in for a new device....

It would be very nice if someone could write a KM plug-in for this open-source (GPL3) product: (called "TRMNL"). It's a $129 (or $15 less if you find the right link), 7.5 e-paper display (with a resolution of 800x480). It runs for 3 months on its battery, although for $10 more, a higher power battery can be purchased that runs for 6 months. I presume it connects to your wireless hub, although I didn't see an explanation of how to configure it to do that.

The device doesn't have any API other than one that takes a bitmap and displays it on screen. That's what I think a KM plugin for it could do, take one of KM's named clipboards and send it to the device. (More details on that below.) It currently has 60 plugins for different apps, which are listed here:

There is currently a plug-in called Image Display which might be a viable workaround (with some work) until there's a native KM plug-in.

By default, the device fetches a JSON string from a free TRMNL web server (but you can change this and use your own server.) I don't fully understand this part of the process.

Writing a plugin for this device to host on their site does cost a one-time fee of $20, I think.

You can find an actual example of someone writing a plug-in on this YouTube page:

The simplest KM plug-in would be one that just copies a KM named clipboard to your device. However it's possible that other kinds of plug-ins might also be useful. For example, a plug-in might take some string data and convert it to a bitmap. Personally, I would like such a plug-in to replicate the functionality of the "Display Text Large" action which fits the supplied text to the size of the screen. (But I don't even know how KM performs this magic.) To me, that's the ideal plug-in.

What they call an "API" is here.

I really really don't like the way they engineered plugins. I mean.. just sell the hardware, open source the software, or publish a proper SDK / API.

What is "improper" about this SDK? Are you looking for power, like built-in fonts? This device doesn't have "power", but leaves the power to you, by giving you only a bitmap. I like it that way. In fact, I would call its design 100% perfect.

My main problem with it is that there is no programmatic interface. You can configure 'plugins' through a UI, but I would not call that an SDK or an API.

Reminds me of StreamDeck. They have a decent SDK for developing plugins but it's so limited. IMO A good API should be open to other languages typically via REST. That's where you will usually get the greatest innovation from the user community.

UPDATE:

Digging a bit deeper I think I've undersold their SDK. There are indeed ways to manipulate the screen programmatically if you design your plugin to accept data via a webhook, or polling. It's growing on me the more I read how it works.

Yes. In fact, the web hook can point to your own server. You don't have to use theirs.