I've since updated the display to show me three different sets of transport information.

At a glance, I can see the next bus, whether there are delays on the Elizabeth Line, and if my regular trains are running.

Here's how all three APIs work.

Bus

The bus is the easiest one of all. Transport for London (TfL) have a set of free APIs. No registration required! You will need to know the ID of your local bus stop. Visit the TfL bus search page and search for your local stop. Click the stop on the map.

You'll be taken to a URl like https://tfl.gov.uk/bus/stop/490000173RF/oxford-circus-stn-margaret-street - that will show you the Bus Stop ID (technically the NaPTAN ID). In this case 490000173RF.

You can then call this API: https://api.tfl.gov.uk/StopPoint/490000173RF/arrivals - which will return JSON like this:

[{
    "$type": "Tfl.Api.Presentation.Entities.Prediction, Tfl.Api.Presentation.Entities",
    "id": "-119695796",
    "operationType": 1,
    "vehicleId": "LTZ1049",
    "naptanId": "490000173RF",
    "stationName": "Oxford Circus Stn  / Margaret Street",
    "lineId": "12",
    "lineName": "12",
    "platformName": "RF",
    "direction": "outbound",
    "bearing": "152",
    "destinationNaptanId": "",
    "destinationName": "Dulwich Library",
    "timestamp": "2023-06-29T10:40:18.3147535Z",
    "timeToStation": 1470,
    "currentLocation": "",
    "towards": "Trafalgar Square Or Green Park",
    "expectedArrival": "2023-06-29T11:04:48Z",
    "timeToLive": "2023-06-29T11:05:18Z",
    "modeName": "bus",
    "timing": {
        "$type": "Tfl.Api.Presentation.Entities.PredictionTiming, Tfl.Api.Presentation.Entities",
        "countdownServerAdjustment": "-00:00:02.7011995",
        "source": "2023-06-29T07:28:52.918Z",
        "insert": "2023-06-29T10:40:01.313Z",
        "read": "2023-06-29T10:39:58.591Z",
        "sent": "2023-06-29T10:40:18Z",
        "received": "0001-01-01T00:00:00Z"
    }
}, {
    "$type": "Tfl.Api.Presentation.Entities.Prediction, Tfl.Api.Presentation.Entities",
    "id": "-1460579610",
    "operationType": 1,
    "vehicleId": "LTZ1447",
    "naptanId": "490000173RF",
    "stationName": "Oxford Circus Stn  / Margaret Street",
    "lineId": "12",
    "lineName": "12",

Hopefully the entity names are self-explanatory. If you need a specific route, you will need to filter on the lineId's value.

Personally, I use timeToStation to see how long until the bus arrives. If it's less than a couple of minutes, I don't display it.

CrossRail

Again, I am overjoyed that TfL have a free API which lets you check the status of various tube lines.

The Elizabeth Line's status can be found at https://api.tfl.gov.uk/Line/elizabeth/status - can you guess the URl for the other lines 😉?

And, again, we get back some fairly self-explanatory JSON:

[{
    "$type": "Tfl.Api.Presentation.Entities.Line, Tfl.Api.Presentation.Entities",
    "id": "elizabeth",
    "name": "Elizabeth line",
    "modeName": "elizabeth-line",
    "disruptions": [],
    "created": "2023-06-27T12:37:57.107Z",
    "modified": "2023-06-27T12:37:57.107Z",
    "lineStatuses": [{
        "$type": "Tfl.Api.Presentation.Entities.LineStatus, Tfl.Api.Presentation.Entities",
        "id": 0,
        "lineId": "elizabeth",
        "statusSeverity": 9,
        "statusSeverityDescription": "Minor Delays",
        "reason": "Minor delays between Stratford and Shenfield due to a an earlier signal failure at Tottenham Court Road. GOOD SERVICE on the rest of the line. ",
        "created": "0001-01-01T00:00:00",
        "validityPeriods": [{
            "$type": "Tfl.Api.Presentation.Entities.ValidityPeriod, Tfl.Api.Presentation.Entities",
            "fromDate": "2023-06-29T10:30:50Z",
            "toDate": "2023-06-30T00:29:00Z",
            "isNow": true
        }],
        "disruption": {
            "$type": "Tfl.Api.Presentation.Entities.Disruption, Tfl.Api.Presentation.Entities",
            "category": "RealTime",
            "categoryDescription": "RealTime",
            "description": "Minor delays between Stratford and Shenfield due to a an earlier signal failure at Tottenham Court Road. GOOD SERVICE on the rest of the line. ",
            "affectedRoutes": [],
            "affectedStops": [],
            "closureText": "minorDelays"
        }
    }],
    "routeSections": [],
    "serviceTypes": [{
        "$type": "Tfl.Api.Presentation.Entities.LineServiceTypeInfo, Tfl.Api.Presentation.Entities",
        "name": "Regular",
        "uri": "/Line/Route?ids=Elizabeth line&serviceTypes=Regular"
    }],
    "crowding": {
        "$type": "Tfl.Api.Presentation.Entities.Crowding, Tfl.Api.Presentation.Entities"
    }
}]

You can grab the text out of there for easy display.

Train Times

This is the only pain-in-the-arse service. It uses National Rail's Live Departure Boards Web Service (LDBWS). This is an XML SOAP API which requires credentials.

Register for an API token at National Rail's site.

Find the three letter CRS code for your departure and arrival station on the National Rail website.

I use the GetDepBoardWithDetailsHeader() API call. For example: GetDepBoardWithDetails(20, "WWA", "LBG", "to") gets the next 20 trains from Woolwich Arsenal to London Bridge.

There are OpenLDBWS libraries available in most major programming languages. Don't bother writing your own!

There's more discussion online about how to test and use OpenLDBWS.

Once you've got a response, you can filter it for the specific trains you're interested in.

Putting it all together

Well, that's up to you Sparky! Personally, I have a hodge-podge of PHP building it into a format suitable for my ancient eInk screen. You can do what you like!

This time, I'm taking a different Nook, and turning it into a magic gallery. Here's what it looks like in action:

Terence Eden is on Mastodon

@edent

Upcycled an old eReader into an art frame.
Displays a new black & white piece of art from Flickr every few minutes.
Full write-up this weekend, but pretty straightforward to do. pic.x.com/ttvrbhz3ee

---

Video

With the front light off:

With the front light on:

How it works

Every few minutes, it finds a black and white artistic image from Flickr and displays it. Simple!

Inspiration

Ambient home cinema by Tom Whitwell

Build

I've previously replaced the battery on an eInk Nook, so I know how easy they are to disassemble. But for this I wanted to keep the plastic frame on, so that I'd be able to attach a more æsthetically pleasing wooden picture frame.

Finding a picture frame of the right size was a little tricky. The physical dimension of the unit are ~170mm x ~140mm. But the screen is only ~125mm x ~93mm .

I used eFrame - they have a really handy website for custom sized frames and inserts. I ordered a mount for an 135mm x 103mm picture (they cut them slightly smaller but I didn't want any overhang) with 20mm top and bottom borders, and 35mm left and right borders. That gave me enough space to fit the Nook. But, as long as the aperture lets you see the eInk, and masks off the plastic frame, you should be OK.

I was also able to buy a frame without a glass front. As this is my first attempt, I went for simple and cheap wood - rather than something more ornate and artistic. Total cost including shipping was £25.

Attaching the frame

It is useful to be able to get to the main "N" button - and there needs to be a gap for the charging cable. I thought about cutting out a little bit of the frame but, in the end, it was easier to attach the Nook to the frame using velcro and blu-tak. Because of the weight of the Nook, I used some sturdy hooks for the wall mount.

Power

There wasn't enough room in the frame for a normal USB cable, so I used a right-angled micro-USB cable. With the page refreshing every 5 minutes between 0600-2300, it got about 3 days of battery life - less if it used the Glow-Light. So a permanent wired connection seemed sensible.

Background

On the surface this seems quite simple - get a bunch of images and display them. But there are some limitations.

The original Nook Simple Touch is, bless it, an old and slow device. I want to do the minimum amount of processing on it as possible. The screen resolution is only 600x800. I don't want to convert colour artwork to black and white - that will just look messy. I also want the image size to roughly match the screen - so things aren't shrunk down.

So, I want a list of art which meets the following criteria:

• Intended for monochrome display⁰
• Roughly 4:3 aspect ratio
• Proper art¹ by real artists²

I started by looking at the Open Data produced by various museums and art galleries. Unfortunately, none of them indicated whether an artwork was greyscale. So, I turned to Flickr!

Using the Flickr API

Sadly, the Flickr API has been neglected for the best part of a decade. So the documentation is grossly out of date.

Two of the undocumented Search API calls are styles and orientation. I use them to search for black and white images in landscape orientation. You can discover more by using the Flickr search website and opening the "Advanced" panel.

The rest of the API call is quite standard. A keyword to search for ("art") - or whatever you want. Sorted by "interestingness" - although popularity is also a good metric. With safe_search turned off - no prudes in our house. And an image size no wider that 800px - because serving a correctly scaled image means less work for the eReader.

The Code

It is almost embarrassing in its simplicity. It uses Sam Wilson's PHP library for Flickr. It grabs 100 images, and then picks a random one to serve. It is resized to fit in a bounding box of 800x600 and repaginated to centre the image. The image is rotated it 90 degrees and served over HTTP with an appropriate caching policy. Nothing else. Here it is³.

require_once 'vendor/autoload.php';
$flickr = new \Samwilson\PhpFlickr\PhpFlickr("123465789");

$search_terms = ["art", "artistic", "painting", "drawing"];
$search_rand = array_rand($search_terms, 1);

$sort_terms = ["date-posted-asc", "date-posted-desc", "date-taken-asc", "date-taken-desc", "interestingness-desc", "interestingness-asc", "relevance"];
$sort_rand = array_rand($sort_terms, 1);

$s = $flickr->photos()->search(["text"        => $search_terms[$search_rand],
                                "per_page"    => "100",
                                "styles"      => "blackandwhite",
                                "orientation" => "landscape",
                                "sort"        => $sort_terms[$sort_rand],
                                "safe_search" =>"3"
                               ]);

$number_of_photos = count($s["photo"]);

$random_photo = random_int(0, $number_of_photos - 1);

$p = $s["photo"][$random_photo];

$farm   = $p["farm"];
$server = $p["server"];
$id     = $p["id"];
$secret = $p["secret"];
$title  = $p["title"];

$image_url = "https://live.staticflickr.com/{$server}/{$id}_{$secret}_c.jpg";

$image = imagecreatefromjpeg( $image_url );

$cropped = imagecropauto( $image, IMG_CROP_DEFAULT );
if ( $cropped !== false ) { 
   imagedestroy($image);  
   $image = $cropped;
}

$x = imagesx( $image );
$y = imagesy( $image );

$width_ratio  = $x / 800;
$height_ratio = $y / 600;

// Scale
if ( $height_ratio >= $width_ratio ) {
   $new_height = ( 600 / $y ) * $x;
   $scaled = imagescale( $image, $new_height, 600 );
} else {
   $scaled = imagescale( $image, 800, -1 );
}

$x = imagesx( $scaled );
$y = imagesy( $scaled );


// Make a background canvas
$canvas = imagecreatetruecolor( 800, 600 );
$black  = imagecolorallocate( $canvas, 0, 0, 0 );
imagefilledrectangle( $canvas, 0, 0, 800, 600, $black );

$dst_x = ( ( 800 - $x ) / 2 );
$dst_y = ( ( 600 - $y ) / 2 );

imagecopy( $canvas, $scaled, $dst_x, $dst_y, 0, 0, $x, $y );

$rotated = imagerotate( $canvas, 90, 0 );

header('Content-type: image/jpeg');
header("Expires: on, 01 Jan 1970 00:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");

imagejpeg( $rotated );

// Tidy Up
imagedestroy( $image );
imagedestroy( $scaled );
imagedestroy( $rotated );

Displaying

As I mentioned in my previous post about displaying web pages on the Nook - the browser is slow, old, and can't handle https connections.

So I used ElectricSign which is an old Android app. Give it a URL and it will display the contents on screen. It can be set to periodically refresh.

I've had it running for months on a different screen and it hasn't crashed.

That's it!

TODO

• Buy more cheap, 2nd hand eInk screens on eBay. Preferably larger and with higher DPI.
• Get some fancy frames.
• Start a pirate art museum.
• Monetise it by tracking how long people stare at a particular artwork.
• BitCoin?⁴

Thanks for reading

If you've enjoyed this blog post, you can buy me something from my wishlist or sponsor my GitHub. Find out more way to support this blog.

End Result

An eInk screen which displays the trains I can catch from my local station.

It shows the next few available trains, and whether they're delayed. It also shows how long until the next local bus to the train station.

Updating the Nook

Before doing anything, manually update the Nook's firmware. You can download the latest version from Barnes and Nobel

Copy the .zip file to the root directory of your Nook via USB. Unplug the Nook and turn it off. After a few minutes, it should detect the file and perform the update.

Sadly, it's only Android 2.1 - and the TLS implementation is artificially restricted. More on that later!

It's worth deregistering your Nook and then resetting it. You have to press a few buttons to use the Nook without a B&N Account.

Rooting the Nook

Download Nook Manager (or compile it yourself from the open source code).

Unzip the file. It should just contain NookManager.img. Write the disk image to a microSD card. Follow the instructions on XDA Developers to root the device.

Changing the Launcher

I used ReLaunchX which is an eInk optimised Android launcher. Download the latest Android version from F-Droid.

With the Nook connected to your computer by USB, run:

adb install com.gacode.relaunchx_200105000.apk

That will install the launcher. When you hit the Nook's home button, you will be able to select it as the default launcher.

Electric Sign

Running a modern web browser on the Nook is close to impossible. So I recommend using Electric Sign. It's an open source Android app which periodically calls a URl, turns it into an image, and then uses it as the Nook's screensaver.

You can download the latest version from APKpure.

Again, install it using:

adb install Electric\ Sign_v1.0.3_apkpure.com.apk

Launch it from ReLaunchX and follow the setup screen. I set it to reload every 5 minutes from 7AM until 9pm.

TLS Woes!

Here's where life gets complicated. The World Wide Web is changing to become more secure. Sadly, this means older browsers simply cannot access modern web servers. Even though B&N have updated the Nook to use TLS 1.3 - it only works with their own servers. Trying to access modern https:// sites just won't work.

So, you will need to point Electric Sign to an unencrypted website.

Train API

UK trains have an open API, the snappily named Live Departure Boards Web Service (LDBWS). You need to register for an API key, which is pretty much instant.

There's a great PHP library for OpenLDBWS. You can also find libraries in most popular programming languages.

I created a quick little page which displays the trains that either my wife or I can catch to get to our jobs. When we're sat eating breakfast, we can see if our regular train is delayed.

Bus

I have an Alexa skill to tell me the bus times - but listening is much slower than reading. So I also added bus times.

You can also see that I've only included trains we can actually catch. There's no point showing a train leaving in 5 minutes if it takes 10 minutes to walk to the station. The train API shows the departure time of delayed trains, so the code takes that into account.

Physical Install

I used a double-sided 3M sticky pad and plonked it on the wall. No fancy hooks, screws, or magnets. Just glue.

It's conveniently close to an electrical socket. But having a trailing wire looks messy. So we'll only plug it in when it needs a top up. I replaced the Nook battery a few years ago so it should last several days without a recharge.

Code

All the code - plus backups of the binaries - are available on GitLab.

What next?

I don't really care about the weather or the news, and there's limited screen space. But if you have any suggestions for what it could display, do let me know.

Hope you found that useful!

Terence Eden is on Mastodon

@edent

Replying to @edentI declare this project complete!
We now have a passive display showing us bus & train times.
Blog post coming up this weekend. pic.x.com/m2emF5rq3e

---

Taking apart the nook is incredibly simple, pop off the power button, use a Torx 5 screwdriver to undo the single screw, and then spludger your way around the edges. This is what I found in mine...

VERY BAD!

A replacement nook battery is less than a tenner from Amazon. It is developed by Cameron Sino who seem to specialise in making replacement batteries for all sorts of gadgets.

Fitting the battery was a little tricky, here's how it went...

There's a small port on the motherboard into which the battery cable is attached.

The cable only fits in one way - with the red wire at the bottom. This is the position which the battery will take when the nook is reassembled.

The battery came charged, so I was able to verify that everything worked as expected. Now's a good time to test charging it.

Once done, unplug the battery and prepare to reassemble!

The back case of the nook has a recessed area for the battery. There's just one tiny problem...

Yup! The battery doesn't fit!

Luckily, the casing for the battery is rather pliable and, with some gentle force, it's just about possible to squeeze it in.

A little bit of tape to secure it into place and we're good to go!

The cable on the battery is long enough to plug in while the back is detached.

Reassembling is somewhat tricky. You have to slide on the bottom, then re-clip everything, and slide up. Be careful not to apply too much pressure - it's really easy to damage the screen that way.

When all the plastic casings are done, it's a simple case of screwing in the T5.

And - that's it! A fairly easy device to replace parts on - no soldering, easy clips, one screw. Why can't all electronics be like this?

Replacement batteries for the nook and glolight are on Amazon for under £10.

I had planned to use a salvaged eInk screen - but the Nook STR (or NSTR from now on) is only £29 due to a massive price drop. The Glow version is a mere £69 - so I bought that and have set my old NSTR to work as a "Family Display Screen".

The idea is that this will stay by the front door, show today's weather, mine and my wife's calendar, as well as other useful bits of information.

Step 1 - Rooting

It's now dead easy to root the NSTR using NookManager.

• Download NookManager from XDA.
• Unzip the file - there should be a disk image in there; "NookManager.img"
• You'll need to use a micro SD card to create a bootable disk. In Linux it's as simple as

  dd if=NookManager.img of=/dev/sdb1 bs=1M

  Windows and Mac users, will have to find tools to help them.
• Turn off your NSTR (hold down the power button on the back, then confirm on screen).
• Stick the micro SD card into the NSTR.
• Turn on the NSTR and follow the on-screen instructions.

And that's pretty much it!

There are, effectively, two options for how to proceed.

1. Point the default browser at a web page and use meta-refresh / JavaScript to update it every so often.
2. Automatically push an image to the NSTR to be used as its default screensaver

One thing that annoys me about the Nook is the fact that you have to register for a Barnes & Nobel account before you can use it. I dislike their geo-restrictive terms and conditions, and the fact that they place advertising on my home screen. I also don't particularly want my reading habits fed back to anyone. No one needs to know that I like reading Star Trek slash fiction, and that I've read chapter 5 of "Spock ♥ Tribbles" seventeen times.

So, here's the quick illustrated guide to running your nook without a bn.com account. There's no scary hacking, formatting of SD cards, or fiddling with computers. This is a ten second hack which just involves tapping a few buttons on your Nook. This works with the original Nook Simple Touch Reader and the new one with GlowLight.

Step 1

Charge your Nook fully. Switch it on using the button on the back. Do not begin the setup process.

Step 2

Hold down the top right page turn button. While holding down the button, swipe the top of the screen from left to right. Release the top right button.

Step 3

A "Factory" button will appear on screen. Press it and you'll be taken to this "Factory" screen.

Step 4

Again, hold down the top right button. While doing so, tap the bottom right corner. A "Skip Oobe" button will appear. Oobe - stands for "Out of box experience".

Step 5

Press the button! Go on, you know you want to :-) You will be instantly rewarded with a homescreen with no adverts and no requirement to sign up for a bn.com account.

Step 6

Enjoy!