This is a Kindle Booklet for SignalK that allows you to open a book on a Kindle Paperwhite that displays pages of graphical instruments that display real time data from a SignalK server on the network.
Kindle UIs are Java Swing applications running inside a lightweight OSGi Framework.
It recognises the mimetype of the "book" and launches the registered Booklet application (SignalkBooklet.java) which then reads the json inside the book file, configures the UI with pages of widgets (EInkTextBox.java).
It then either attempts to connect to a list of host port combinations from the book json. When it connects it also fetches the current state from the Signalk REST API as TCP only provides updates and some slow polling sensors may not get an update for some time. (Perhaps SignalK TCP should send the intial state on connect.)
When the booklet is running navigation is by finger swipes left and rig ht to change pages.
Multiple books may be added to the kindle over the USB Mount, placed in the documents folder. see config.json for an example of configuration.
Dont expect fantastic graphics animations. Kindle screens are great in full sunlight, but the eink technology is very slow and requires careful slow redrawing to avoid shadows and ink left behind. The Paperwhite 4 is IP68 waterproof and the battery lasts for many many hours.
You can run locally (Main.java)
see https://wiki.mobileread.com/wiki/Kindle_Touch_Hacking#Architecture worth reading to understand the internals before trying to use this project.
To use this app you need to get a developer key onto the Kindle. Recent Kindles have USBNetworking that allows you to login as root over IP (default password mario, as per https://www.sven.de/kindle/), put the root drive into writable and install your developer key. You can also use packages from https://wiki.mobileread.com/wiki/Kindle_Touch_Hacking#Architecture to automate this however you may need to disable firmware updates to prevent your key from being deleted.
All Jars running on a Kindle must be signed by a key loaded onto the kindle so this step is required.
The maven build produces an installable package that can be installed with the MPRI package installed that is part of KUAL, however it has some dependencies.
AFAIK, Amazon doesn't distribute a Kindle SDK, and I can't distribute it, so you have to extract the API Jars from your Kindle. Copy the contents of /opt/amazon/ebook on the Kindle which should be symlinked to opt_amazon_ebook. That tree contains the SDK. This version of the code is being built against Firmware version 5.10.0.1. Some of the classes are obfuscated and you may have to adjust the code here if your Firmware is different.
The Java version on a Kindle is an embedded JVM based on 1.8 (cvm). It has a cut down list of classes so many standard libraries wont work. You will find a list of all classes in /usr/java/lib/classlist. The version of Swing is different from a standard JDK with some methods missing and some behaviours different. Font point sizes dont correlate well to a standard JDK after taking into account screen resolution. There are a number of Jars loaded into the OSGi framework, however Booklets do not seem to be loaded as OSGi bundles and the normal classpath resolution process doesnt appear to work. You cant embed libraries into a jar and must unpack all the classes into the Jar that are required for a booklet. Simple JSON is available, but even simple things like parsing yaml with standard libraries doesnt work.
The final packaging and signing is performed using kindletool which can be found here https://github.com/NiLuJe/KindleTool
Building is achieved using mvn clean install. It will build the jar, build the package and put the result in target
Copy the install image onto the kindle and run the MRPI package script. This will install the package and restart the Kindle UI.
eg
mvn clean install && \\
scp target/Update_Signalk_uk.co.tfd.kindle.signalk_976ed_install.bin root@192.168.15.244:/mnt/us/mrpackages && \\
ssh root@192.168.15.244 "/mnt/us/extensions/MRInstaller/bin/mrinstaller.sh launch_installer"
192.168.15.244 is the USBNet IP address of the Kindle when plugged in.
slf4j logs to /var/tmp/signalk.log The slf4j settings are in the SignalkBooklet class. They must be set before any SLF4J classes are created.
Create files in /mnt/us/documents called .signalk containing json (eg /mnt/us/documents/OnDeck.signalk), see src/test/resources/config.json for an example.
By default the booklet will discover the Signalk server using mDNS, although if that doesnt work you can configutre a list of servers to try and connect to. The booklet will attempt to connect to each server in turn, backing off from failed servers for 30s. Process is displayed on the UI status screen with diagnostics going into the log file.
For mDNS to work on the Kindle the IP firewall on the kindle must be adjusted to allow the multicast packets on port 5353 be be sent and recieved. If running on a isolated network with no default router dont forget to add a default route to the routing table on the Signalk server otherwise packets wont get routed off the signalk server. This can be done by making the wifi network interface the router.
For the kindle firewall append the following to the UDP rules and restart the firewall.
-A INPUT -m pkttype --pkt-type multicast -j ACCEPT
-A FORWARD -m pkttype --pkt-type multicast -j ACCEPT
-A OUTPUT -m pkttype --pkt-type multicast -j ACCEP
Once discovered the booklet will fetch the state of all data values every 5m from the http interface and process updates on the tcp port.
The app comes with a set of default datavalues and widgets, however you can configure more datavalues and attach widgets to them. DataValues have a path in the store which input values map to so that data updates with a matching path are collected by the data value. Some datavalues may collect updates from multiple paths. The datavalue will have SI units, and a type that determines how its units are treated and displayed.
instruments display datavalues. An instrument has a key, a widget class and a path in the store that identifies which datavalue it displays.
Screens are built using default and custom instruments.
{
"servers" : [
{
"host": "192.168.4.1", // TCP IP
"port": 8375, // TCP port
"url": "http://192.168.4.1:3001" // REST API
},
{
"host": "192.168.1.134",
"port": 8375,
"url": "http://192.168.1.134:3000"
},
{
"host": "x43543-3.local",
"port": 8375,
"url": "http://x43543-3.local:3000"
}
],
"datavalues": { // customised data values
"temperature.engine" : { // primary key in store.
"paths": [ // optional additonal paths, may be empty, but is required
"additonalpath"
],
"unit": "M", // units one of RAD, MS, RATIO,M, MAP, K, TEXT
"dataType": "depth", // datatype one of SPEED, BEARING, DISTANCE, NONE, RELATIVEANGLE, LATITUDE, LONGITUDE, TEMPERATURE, PERCENTAGE, DEPTH
"description": "example",
"dataClass": "DoubleDataValue" // one of DataValue, DoubleDataValue, CircularDataValue,
// PilotDataValue, FixDataValue, PossitionDataValue,
// CurrentDataValue, AttitudeDataValue
}
},
"instruments": { // customised instruments
"awscorrected": {
"widget": "EInkTemperature", // one of EInkTextBox, EInkAttitide, EInkBearing, EInkCurrent, EInkDepth, EInkDistance,
// EInkLOg, EInkPilot, EInkPossiton, EInkRatio,
// EInkRelativeAngle, EInkSpeed, EInkTemperature
"path": "temperature.engine" // Path to data in datavalues.
}
}
}
"screensize": { "w":1072, "h":1448 }, // only for non kindle displays "pages" : [ // list of pages { /* the values of instruments may be one of the following and any custom instruments defined.
awa, Apparent Wind Angle
aws, Apparent Wind Speed
twa, True Wind Angle
tws, True Wind Speed
stw, Speed Through Water
dbt, Depth Below Transducer
vmg, Velocity Made good into or down wind.
var, Variation
hdt, Heading True
cogm, Course over ground magnetic
hdm, Heading True
lee, Leeway (angle)
pstw, Polar Speed Through Water
psratio, Polar Speed Ratio
pvmg, Polar VMG
ttwa, target optional true wind angle upwind or downwind
tstw, target stw at ttwa
tvmg, target vmg at ttwa
pvmgr, polar vmg ratio
twdt, true wind direction true
twdm, true wind direction magnetic
tackt, heading on opposite tack true
tackm, heading on opposite tack magnetic
ophdm, target opposite heading true
cogt, course over ground true
rot, rate of turn
rudder, rudder angle
sog, speed over grount
twater, water temperature
stwref, stw sensor type
blank, blank widget
log, log
attitude, pitch and roll
current, set and drift
fix, gps fix information
pilot, pilot information
position, possition
*/
"instruments" : [ // rows and columns of instruments, using custom and pre-defined widgets.
[ "awa", "twa", "stw", "psratio" ],
[ "aws", "tws", "pstw", "pvmg" ],
[ "cogt", "sog", "attitude", "lee" ],
[ "position", "fix", "log", "dbt" ],
[ "position", "fix", "log", "dbt" ]
],
"vspace" : 5, // space between widgets
"hspace" : 5,
"id" : "page1", // page ID
"rotate": true // if true, rotate into landscape.
},
{
"vspace" : 5,
"instruments" : [
[ "awa" ],
[ "aws" ]
],
"id" : "page2",
"hspace" : 5
},
{
"id" : "page3",
"hspace" : 5,
"vspace" : 5,
"instruments" : [
[ "awa", "twa" ],
[ "blank", "blank" ],
[ "blank", "blank" ],
[ "blank", "blank" ]
]
},
{
"id" : "page6",
"hspace" : 5,
"vspace" : 5,
"rotate": true,
"instruments" : [
[ "awa", "twa" ],
[ "blank", "blank" ]
]
}
]