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Hacking an EL-wire Inverter

I recently discovered electroluminescent wire or short EL-wire. It's this cool wire that glows when you apply a current. I had the idea to illuminate our Whiskey cabinet (which really is an old ammunition crate) when you open it.

elwire.jpg I bought a meter of orange wire off eBay for about 7 Euro. EL-Wire requires an inverter that converts DC to AC power. My wire came with a simple one that takes two AA batteries.

Unfortunately that EL driver has a push button that switches through three modes when clicked: on, blinking and off. Since I only need on and off controlled by a DPDT switch, I had to figure out how to hack that onto the controller. Turns out it isn't too hard:

  1. Unscrew the one screw at the back and open the controller
  2. Use a screwdriver to gently push the battery contacts out of the plastic to get access to both sides of the PCB
  3. Flip the PCB upside down and desolder the push button
  4. Add wires through the holes and solder them onto the two contacts on the side of the switch that's closer to the battery (A+B)
    • this overrides the three mode behavior controlled by the microchip under the white blob
    • if you want to keep the three mode behavior but just need a longer trigger cable you can also use the original switch solder points (A+C)
  5. Move the new wires back through the switch hole
  6. Optionally apply some hot glue to the transformer in hope of muffling the high pitched noise a bit
    • didn't have much effect for me
  7. Solder your switch to the other end of the new wires
  8. Reassemble everything

Here are the steps as photos again:

Last updated: 2018/04/09 23:44 · Permalink · Comments

Custom reMarkable Sleeve

The “folio” the reMarkable comes with (if you preorderd) seems to be universally hated for it's low quality and not being very practical either. I wasn't very fond of it myself.

This weekend I tried to make a new sleeve that's more notebook like. I used some purple leather I bought in a store right around the corner. I added some cardboard, glue and a super magnet and made a thing…

Last updated: 2018/02/11 16:10 · Permalink · Comments

File Sync API for reMarkable Tablet

TLDR; I got a new pricy gadget and I wrote some software for it.

I got a new toy: the reMarkable ePaper Tablet.

When I first saw the kickstarter campaign, I immediately wanted it, but I was unsure if they would ever deliver so I didn't back it. I figured when they're successful I can just regularly buy it. It's a decision I regret. Because the reMarkable now retails for 629 EUR while the early preorders started at $379. So expensive! So I tiptoed around the decision to buy one for weeks. In the end I bought one on eBay for about 500 EUR.

The video above gives you a pretty good overview on the pros and cons of the tablet. And before you ask: no, it does not do OCR on your notes.

So why would I buy a very limited device for a price that would buy me a more powerful Android tablet? Because this is what I always wanted. Ever since I saw the very first e-Paper displays. A device that I can just “print” anything to and then scribble on that. A device that feels like paper, but with easy digital archiving and no media breaks. And in that, the reMarkable absolutely delivers.

So what about the software? As the video mentions, there are some kinks in the software on the tablet it self, but the reMarkable people already fixed a few in the update that came out a couple of weeks ago. But what is really good about this tablet is how open it is. It is running Linux, has a running SSH daemon by default and the root password can be accessed from the menu. People already started to write their own software and sharing tips on how to customize the device in a wiki.

One thing nobody had looked at so far, was how the cloud syncing work. As mentioned in the video, the tablet syncs files between itself and the mobile and desktop apps. It's the easiest way to get PDFs on the device. However those desktop apps are somewhat limited.

So I went ahead and tried to figure out how the syncing actually works. Luckily it turns out to be a relatively simple, HTTP and JSON based API. So over the last few days I documented my findings and created a PHP library to talk to the API.

The repository also includes a command line client that can list, download, upload and delete files on the tablet through the sync API.

Eg. the following would copy a PDF from my home directory into the specified folder on the reMarkable.

./remarkable.php ~/mypdf.pdf /work/Projects

The nice thing about using the sync API is that I don't need to be in proximity to the tablet. Eg. right now it's on my desk at the office but I can still easily push documents to it from home.

It would also be easy to integrate pushing documents to the tablet into existing web apps. How about a DokuWiki button that automatically creates a PDF from the current page and puts it on the reMarkable? Or a service that let's you forward emails to your tablet?

I currently have no concrete plans other than using the command line tool, but I do hope my work inspires and helps others to do more awesome things.

remarkable, review, sync, api, php, gadget
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Last updated: 2018/02/02 15:31 · Permalink · Comments

DIY Board Game

Last weekend I felt like I wanted to create something with my hands again instead of sitting in front of my computer for hours. So I looked for a little project that wouldn't take too much time. Of course I spent more time than anticipated.

Originally I only wanted to build my own version of Quoridor which I found on BoardGameGeek. But then I saw that I could easily support the Viking game Hnefatafl as well if I'd just make the board a little bigger…

For Quoridor I needed walls that could be put up beween the individual fields. At the local hardware store I found a mat with small marble mosaic stones. For the walls I bought an aluminum slat that I cut into pieces with a Dremel.

Ideally the aluminum walls should have fitted between the stones on the mat, unfortunately the stones weren't glued on it precise enough. I ended up ripping them off the map, sanding the glue off and hot gluing them back on a piece of plywood. It only took me three or four tries to get the distance correct :-?

For the box/cover I built a simple plywood box. At first I thought about nailing it together but that proved to be difficult and the wood began to splinter. So I used wood glue and a rubber band to hold it together while the glue dried.

To decorate the box I transferred the print of a viking ship drawing to the box by making my own carbon copy paper by blackening the back with chalk. I then transferred the lines by tracing them with an edge. Finally I carved the lines with my Dremel and stained the wood.

The pawns I ordered from whose owner was very helpful when I fucked up my order by failing to count how many pieces I really needed.

I think the end result is pretty enough.

diy, boardgame, games
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Last updated: 2018/01/12 16:45 · Permalink · Comments

Network Trouble

So here's a story about how I spent my weekend.

I am dissatisfied with my home network, mostly with the network capabilities available in the bedroom. Because, as you know, Kaddi and I like to play adventure games on the Steam Link which needs enough bandwidth and low latency to be able to stream the game from my PC to the TV.

So in general, Wi-Fi sucks at my place. I measured it right next to the access point and on 5GHz I get a meager 23 Mbit/s. 2.4ghz is even worse. I guess it's just because the airspace is totally overcrowded - I see about twenty or more different networks.

Since I rent a place, there's no sensible way to set up network cables. So my network relies on Power LAN. Which is Voodoo. Everyone knows that it never ever reaches the advertised speed outside a lab. But I'm not asking for much. I had a couple of 650 Mbit connectors mixed with some older 200Mbit ones. And connection speeds in the bedroom were horrible. The Steam Link just did not work with that. With the sucky Wi-Fi it was at least somewhat usable - lots of freezes, stutters and shit, but bearable for slow paced adventure games.

So I thought maybe it would help to replace my mix of Power LAN adapters with all the same ones. I ordered four 1200 Mbit ones and it turned out okay in the hallway where speeds now reach up to 450mbit. However in the bedroom it still was not much more than 10 MBit.

Now because I know that Power LAN is Voodoo, I tried the power socket in the hallway right next to the bedroom door and that brought about 110 Mbit. Not too bad. I then switched the new 1200 adapter for an old 650 one and the speed was still about 110 MBit. So I guess it makes not a difference if you mix different speeds as long as they are nominally higher than what you can realistically reach.

So the new plan was this: send back two of the 1200 MBit adapter and use the old 650s instead. Use the hallway socket and lay down a cable into the bedroom. Not terribly sexy but bearable from an aesthetics standpoint.

However I need to connect two devices, the Smart TV (for Netflix and Youtube) and the Steam Link. So I needed a switch. I ordered a network cable and a switch from Amazon on Friday and they offered free same day delivery. Woot! I waited eagerly all day. DHL package tracking sucks though - you barely get any info until the mailman rings. The package finally arrived around 8pm. When I unpacked the switch, I properly read the labeling for the first time: “Fast Ethernet”. Shit, that's 100MBit max. I wanted my 110Mbit!

Back to Amazon on a Friday night. I picked a slightly more expensive Gigabit switch than necessary, just to be eligible for free overnight shipping.

The next day, Kaddi and I spend some time for neatly laying out the network cable, reordering aand fixing up all the other cables with cable ties - you know, making everything neat. Because in all those years I still seem not to have learned a thing about doing this kind of shit before testing the setup…

Anyway the new switch arrives in the evening and we hook it up and decide it's time for a game.

I boot up the Steam Link and it says that it cannot connect to the network and then freezes up. Shit. Reboot. This time we manage to start the game. Which freezes and stutters. A lot. Like unbearable lot.

I notice the lights on the switch behave weird. They flicker as they should for a while, then they all go out at once, then come back up all together again. A bit of flicker and the same spiel again. As if the switch is resetting constantly.

What the actual fuck? I have no idea what that's supposed to be. So I grab one of my old 100 Mbit switches I still have lying around and wire it up instead. It works. From time to time the game stutters a bit with a slow network warning, but not too often. Maybe a bit less than it did when we used the Wi-Fi before.

So, I guess there's another piece of hardware going back to Amazon. I spent a lot of time and in the end, didn't really achieve anything. I dunno what the moral of this story is. But this is my blog. If there's any place where I can tell pointless stories, it's here.

network, powerlan, wifi
Last updated: 2017/11/12 20:15 · Permalink · Comments

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