KANIVIS Knowles Audible Navigation for Visually Impaired Sailors
Introduction
KANIVIS is a smartphone application designed to help blind and visually impaired sailors with the process of sailing and navigating a boat. It connects to the boat's data bus that carries information from the boat's instruments, and then reads aloud on-demand various data concerning the boat's navigation. It beeps to indicate a material change in depth. It can be set to generate audible beeps to indicate that the boat is off-course.
The interface to the application is a grid of large buttons designed to present an easy to use and intuitive system. There is audible feedback to all operations.
General points
Please note that the application is entirely "read only", that is, it will never cause any change to the operation of the boat. So, for example, the various steering functions change only the application's notion of a target course or wind angle; this will in turn possibly change the off-course alarms, but it will not impact, ever, the operation of an autopilot or the rest of the boat's navigation.
The application is only as good as the boat's data bus. If the boat's bus does not provide, for example, TWA, then nor will KANIVIS. KANIVIS makes no attempt to calculate any values - it only records and relays data received from the NMEA bus.
Initial configuration
The only operation required to initialise the application is to define the endpoint to which the application should connect in order to receive the boat's data. This configuration needs to be done once only, and will only change if the boat's nav system changes or the user is aboard a different boat. Values are stored, and recalled next time the app is started.
This element alone might require the assistance of a sighted person with access to, or knowledge of, the boat's data systems,
This short document does not attempt to detail the many possible ways to connect to a boat's data bus, only to present a typical example. Let us assume that the boat has a system that has a WiFi access point called MyBoat. First connect your smartphone to the MyBoat access point. With this complete, you must ascertain the IP address and port number of the NMEA0183 data stream. The IP address might be, for example, 192.168.0.10; the port number is often 10110. Open KANIVIS, and use the so-called "hamburger menu" button in the top bar of the application to reveal a "connection" option. Select this, and enter the IP address (or name) and port number, as discovered above. Tap the Submit button, and you're done. The main KANIVIS screen is now visible and ready to use, and you are in command mode.
Command mode
The application starts in Command Mode. This comprises a grid of buttons in 3 columns of 5 rows. It is perhaps simplest to think of the buttons from top to bottom as the digits on a phone dialler, with a fourth row reading
- 0 £
and a fifth row reading
- Enter +
The functions of the buttons are as follows, detailed explanations follow.
1: Announce Apparent Wind 2: Announce True Wind 3: No function currently assigned 4: Announce Position 5: Announce Time (UTC) 6: Announce Waypoint information 7: Announce Heading 8: Announce Speed 9: Announce Trip *: Set or switch steering mode: compass or wind, explained below 0: Announce Depth £: Switch to number mode -: Port 10 if steering to compass, or Bear Away 10 if steering to wind Enter: Switch to Options mode +: Starboard 10 if steering to compass, or Luff Up 10 if steering to wind.
Most of the functions are self-explanatory, or will be as soon as they are tried; but some require further explanation.
Setting a course
When a course has been set, KANIVIS will give an audible warning akin to a parking sensor, indicating that the boat is off course and so enabling the helmsman to adjust to bring the yacht back on course. The tone of the beeps is lower or higher depending on whether the boat is to port or to starboard of its intended course. The frequency of the beeps increases the more the boat is off course; up to 10 degrees off course there is no warning, between 10 and 30 degrees there is an increasing beep rate; over 30 degrees the beep rate is consistent and fast.
We now examine the ways in which the target course can be set; there are many!
Firstly, the application may be set to steer to an apparent wind angle, or to a compass course. When the steer button is pressed for the first time, it will start tracking at the current compass course. If the steer button is pressed again, it will switch to tracking the current apparent wind angle. A further press will revert to compass mode.
If a new course has been indicated by the navigator, it is often useful to press the steer button twice in quick succession, which has the effect of resetting the current compass or wind-angle being tracked to match the boats current direction.
The tracked angle can be increased or decreased by ten degrees by pressing the Port or Starboard buttons.
If you are steering to wind, then the Port 10 and Starboard 10 button change meaning slightly to mean Bear Away or Luff Up, respectively.
To enter a specific compass course, or a specific wind angle, you must be in either steer-to-compass or steer-to-wind mode. The only time you will not be in one or the other mode is when the application is first started. Once the Steer button has been pressed one or more times, you will be alternately in either compass or wind mode. To set and explicit angle to track, press the Number button, which moves to Number entry mode. KANIVIS announces that the system is in Number mode, and then an absolute or relative number may be entered using the buttons on the screen with the usual phone-dialler positions. A relative number is entered using the + or - keys on the left and right of the fifth row before entering the number. Numbers must be less than 360; if you attempt to enter a number greater than this, it will cancel number entry and return to Command mode. If you specifically want to cancel number entry mode, you can either deliberately enter an excessively large number, or you can press the £ key.
If you have correctly entered the number you want, then press Enter to have it accepted and applied.
Let's consider a series of illustrative examples. You are currently steering to a compass course of 320 degrees. The navigator indicates that she would like to move to a heading of 305 degrees. You press
Number 3 0 5 Enter
Later, the navigator asks you to steer 10 degrees to starboard. Press Starboard. Then the navigator asks you to ignore the compass and maintain this wind angle. You press the Steer button which switches to Wind mode, setting the target angle to be the currently observed angle. A little while later there is a wind shift and the navigator asks you to luff up 10 degrees: you press the Stbd button. Recall that in wind mode, the Stbd button is interpreted to mean luff up (reduce the AWA), and the Port button means bear away (increase AWA).
Options mode
To enter options mode press the enter key at the centre of the bottom row. When you are in Options mode the screen is still divided into three columns as usual. Button 1 gives a short description of the functions of each of the buttons active in options mode. To leave Options mode, and save any changes you may have made, press the enter key a second time which takes tyou back to Command mode.
The center and right hand columns are, respectively the Reduce and Increase buttons, with the rows being, from top to bottom:
Pitch Speech Speed Speech Volume Sensitivity
Pitch, speed, and volume are self-explanatory. Sensitivy governs the rate of beep increase as the boat moves away from its intended course or wind angle. Higher sensitivities will cause the beeps to accelerate sooner; lower sensitivities more slowly.
Other features
KANIVIS will provide an audible up-chirp, or down-chirp if the reported depth changes by more than 10% of its previously chirped (or spoken) value.
The depth chirps can be disabled and enabled using a long press on the Depth button.