Damian Mehers' Blog Evernote and Wearable devices. All opinions my own.

29May/150

Updating the Pebble Emulator python code

I recently wanted to make some changes to the Pebble emulator, which uses the PyV8 Python-JavaScript bridge to emulate the phone environment running your phone-bases JavaScript companion app.Screenshot 2015-05-29 12.46.07

These are some notes on how I did this, mainly so that I remember if I need to do it again, and also just in case it helps anyone else.

The first thing I did was to clone the Pebble Python PebbleKit JS implementation, used in the emulator. The original is at https://github.com/pebble/pypkjs and mine is at https://github.com/DamianMehers/pypkjs

Once I'd done that I cloned my one locally onto my Mac, and followed the instructions to build it.

It needs a copy of the Pebble qemu open source emulator to which to talk, and I started off trying to clone the Pebble qemu and build it locally.  Half-way through it occurred to me that I already had a perfectly good qemu locally, since I already had the Pebble Dev Kit installed.

By running a pbw in the emulator, with the debug switch enabled, I was able to determine the magic command to start the emulator locally:

Screenshot 2015-05-29 12.51.32

I copied the command, added some quotes around parameters that needed them, and was able to launch the emulator in one window:

Screenshot 2015-05-29 12.51.32

The phone simulator in another window:

Screenshot 2015-05-29 12.54.04

And then my app in another:

Screenshot 2015-05-29 12.55.08

Once I was up and running I started making changes to the Python code.  Since I've never written a line of Python before I made liberal use of existing code to make the changes I needed.

It all ended well when my pull request containing my changes to support sending binary data was accepted into the official Pebble codebase, meaning that Evernote now runs in the emulator.

Filed under: Pebble No Comments
26May/150

Capture your Mac screen activity into daily videos

Screenshot 2015-05-26 14.42.37I know I'm not alone in wishing there was a TimeSnapper equivalent for the Mac.  Among many things it lets you look back in time at what you were doing on your computer minutes, hours or days ago.

Perfect for remembering what you were doing yesterday, and even to recover stuff that was displayed on your screen.

Inspired by TimeSnapper, I've created a small bash script that I've called MacBlackBox which takes regular screen-shots every few seconds. Every hour it combines the screenshots into an mp4 video, and every day it combines the hourly videos into daily videos, one per screen.

It is available in GitHub here.  Happy to accept improvement suggestions.

Filed under: Uncategorized No Comments
24May/150

Keeping your Moto 360 alive while charging

moto350_charging

If you are developing using the Moto 360 and debugging over bluetooth, you'll notice the battery plummeting quickly.

If you put the watch on a QI charging pad, the Moto 360's charging screen kicks in, and you can no longer do anything on the watch, although if you launch your app via Android Studio, it will run.

If you still want to use your watch while it is charging, root it, and disable Motorola Connect on the watch using:

adb -s 'localhost:4444' shell
$ su
# pm disable com.motorola.targetnotif

This works for me, although I am sure it stops plenty of other things from working, so only do this on a development device, and at your own risk.

Filed under: Uncategorized No Comments
16Mar/150

On Pulse: Why your basal ganglia and wearables were made for each other

I just posted Why your basal ganglia and wearables were made for each other

Filed under: Wearables No Comments
22Feb/150

On Pulse – How I got my dream job: My wearables journey at Evernote

I just wrote on LinkedIn's Pulse about How I got my dream job: My wearables journey at Evernote

Filed under: Uncategorized No Comments
22Jan/151

Scrolling long Pebble menu items

This is a technical blog post.  Warning: contains code.

We recently pushed version 1.2 of Evernote for the Pebble to the Pebble App Store.  It is a minor release, with one bug fix, and one new feature.

The bug fix is related to support for the additional character sets that Pebble can now display.

The enhancement is what this blog post is about.  Since we released the first version of the app, which was generally well received, we’ve received emails from people complaining that their note titles, notebook names, tag names etc. don’t fit on the Pebble screen.  They are cut off, and hard to read.  People asked if we could make menu items scroll horizontally if they didn’t fit.

My response was generally something along the lines of “sorry, but we use the Pebble’s built-in menuing system, and until they support scrolling menu items horizontally, we can’t do anything”.  I never felt great about this response, but it was the genuine situation.  However before I pushed the 1.2 release with the character-set bug-fix, I thought I’d take a look at scrolling the menu items.  Turns out, it was surprisingly easy.

You can see what I’m talking about here:

 

The funny thing about the Evernote Pebble watch app is that it knows almost nothing about Evernote.  The Evernote intelligence is all delegated to the companion app that runs on the Phone.  The watch app knows how to display massive menus (paging items in and out as necessary), checkboxes, images, text etc. 

When the user scrolls to a new menu item, we kick off a wait timer using app_timer_register waiting for one second.  If the user scrolls to another menu item before the timer has expired, we wait for a new second, this time using app_timer_reschedule:

static void selection_changed_callback(Layer *cell_layer, MenuIndex new_index, MenuIndex old_index, 
void *data) {
WindowData* window_data = (WindowData*)data;
window_data->moving_forwards_in_menu = new_index.row >= old_index.row;
if(!window_data->menu_reloading_to_scroll) {
initiate_menu_scroll_timer(window_data);
} else {
window_data->menu_reloading_to_scroll = false;
}
}

The above method is called by the Pebble framework when the user scrolls to a new menu item.  The check for menu_reloading_to_scroll is called to work around some behavior I’ve seen.  This callback invokes the following method:

static void initiate_menu_scroll_timer(WindowData* window_data) {
// If there is already a timer then reschedule it, otherwise create one
bool need_to_create_timer = true;
window_data->scrolling_still_required = true;
window_data->menu_scroll_offset = 0;
window_data->menu_reloading_to_scroll = false;
if(window_data->menu_scroll_timer) {
// APP_LOG(APP_LOG_LEVEL_DEBUG, "Rescheduling timer");
need_to_create_timer = !app_timer_reschedule(window_data->menu_scroll_timer,
SCROLL_MENU_ITEM_WAIT_TIMER);
}
if(need_to_create_timer) {
// APP_LOG(APP_LOG_LEVEL_DEBUG, "Creating timer");
window_data->menu_scroll_timer = app_timer_register(SCROLL_MENU_ITEM_WAIT_TIMER,
scroll_menu_callback, window_data);
}
}

As you can see it uses a WindowsData structure, which is a custom structure associated with the current window via window_set_user_data.  Once the timer expires it calls scroll_menu_callback:

static void scroll_menu_callback(void* data) {
WindowData* window_data = (WindowData*)data;
if(!window_data->menu) {
return;
}
window_data->menu_scroll_timer = NULL;
window_data->menu_scroll_offset++;
if(!window_data->scrolling_still_required) {
return;
}

// Redraw the menu with this scroll offset
MenuIndex menuIndex = menu_layer_get_selected_index(window_data->menu);
if(menuIndex.row != 0) {
window_data->menu_reloading_to_scroll = true;
}
window_data->scrolling_still_required = false;
menu_layer_reload_data(window_data->menu);
window_data->menu_scroll_timer = app_timer_register(SCROLL_MENU_ITEM_TIMER, scroll_menu_callback,
window_data);
}

This code is called once when the timer initiated by initiate_scroll_menu_timer expires (after the one second delay), and then it invokes itself repeatedly using a shorter delay (a fifth of a second), until the menu item is fully scrolled.  The call to menu_layer_reload_data is what causes the menu to be redrawn, using the menu_scroll_offset to indicate how much to scroll the text by.

This is the method that gets called by the draw_row_callback to get the text to be displayed for each menu item:

void get_menu_text(WindowData* window_data, int index, char** text, char** subtext) {
MenuItem* menu_item = getMenuItem(window_data, index);
*text = menu_item ? menu_item->text : NULL;
*subtext = menu_item && menu_item->flags & ITEM_FLAG_TWO_LINER ?
menu_item->text + strlen(menu_item->text) + 1 : NULL;
if(*subtext != NULL && strlen(*subtext) == 0) {
*subtext = NULL;
}

MenuIndex menuIndex = menu_layer_get_selected_index(window_data->menu);
if(*text && menuIndex.row == index) {
int len = strlen(*text);
if(len - MENU_CHARS_VISIBLE - window_data->menu_scroll_offset > 0) {
*text += window_data->menu_scroll_offset;
window_data->scrolling_still_required = true;
}
}
}

The bolded code “scrolls” the text if the row corresponds to the currently selected item by indexing into the text to be displayed, and indicating that scrolling is still required.  I’m not happy with using the fixed size MENU_CHARS_VISIBLE to decide whether or not to scroll – it would be much nicer to measure the text and see if it fits.  If you know of a simple way to do this please comment!

The final thing I needed to do was to actually send longer menu item text from the phone to the watch.  Since Pebble now support sending more than 120 or so bytes this was much easier.  I’m sending up to 32 characters now.

In summary I’m simply using a timer to redisplay the menu, each time scrolling the current menu item’s text by indexing into the character array, and I stop the timer once it has all been displayed.

Filed under: Pebble, Wearables 1 Comment
19Nov/144

WatchKit Error – unable to instantiate row controller class

Trying to create a simple WatchKit table, I hit the error shown in this blog post title.

You mileage may vary, but the eventual cause was that when I added my custom RowController class I accidentally added it to the wrong module … I added it to the main iOS app (WatchTest) instead of the Watch extension:

image

The first hint of this was when I was trying to reference the RowController when calling rowControllerAtIndex, and my custom row controller class could not be found:

var rootRow = rootTable.rowControllerAtIndex(0) as RootRowController

By this time I’d already set it as the RowController class for my table’s row in the storyboard, and had inadvertently referenced the wrong module:

image

I fixed the compilation error by adding my custom RowController to the Watch extension module, but accidentally added it to both modules:

image

Everything compiled but when I ran the log shows the error from the title: Error - unable to instantiate row controller class

image

I eventually figured out my mistake, and made sure that the row controller only belonged to the extension module:

image

And I made sure the correct module was referenced when defining the RowController in the storyboard:

image

It would be nice if the Watch App’s storyboard only saw classes in the Watch Extension’s module.

Filed under: Apple Watch, Swift 4 Comments
2Nov/141

Using the Evernote API from Swift

There is a fine Evernote iOS SDK complete with extensive Objective C examples.  In this blog post I want to share what I did to get it working with Swift.

First I created a new Swift iOS app (called “orgr” below), then I copied the ENSDKResources.bundle and evernote-sdk-ios sources ….

image

… into the new project, and added references to MobileCoreServices and libxml2 per the SDK instructions.

image

In order for the Swift code to see the Evernote Objective C SDK, I enabled the compatibility header and pointed it to a header in the SDK that included all the other headers I needed.

image

I also found (YMMV) that I needed to add a reference to the libxml2 path under Header Search Paths

image

Once I’d done this, I was able to build.  Next it was simply a question of translating the Object C example code to Swift.  This is the minimal example I came up with:

image

You’ll need to replace “token” and “url” parameters with the values you can obtain using the developer token page. This simple example just logs my notebooks.  Next steps are for you …

Filed under: Evernote, iOS 1 Comment
20Oct/140

Eyeglasses are broken

My eyeglasses are broken, and I want them fixed.

I vividly remember the morning I woke up, and could no longer read.

Everything was blurry, and no matter how much I blinked away the night, I still could not read.  I could see things further off, and if I moved my phone well back past my normal reading distance, I could still just about focus.

Eventually my eyes could focus as normal, and I put the experience down to tiredness.  But soon the blurriness came back, and didn't leave.  I was being abruptly welcomed into late middle age.  I needed reading glasses.

I picked up a pair of cheap glasses from the local supermarket, and miracle of miracles, I could read again.  Everything was fine and crisp, even when I used the smallest font on the kindle app.

There was, however, still an issue.  When I was wearing my reading glasses, and I was looking at something that wasn't a book, that was further away, say a person's face, or a stop sign, everything was blurry.  I had to take my glasses off to see beyond the page in front of me.

So, in this age of miniaturized sensors, 3D printers, new material science, why can I not buy a pair of glasses that sense how far away objects are that the glasses are pointing at, and physically deform the lenses appropriately to bring items into focus for the wearer

For me the lenses would become clear glass when looking at something in the distance, and would deform to +0.5 reading glasses when looking at a page in front of me.

There have been similar attempts in the past, but as technology advances, sensors become smaller and motors become miniaturized I think its time to look once again at eye-glasses.  The way they work now is broken.  If Google invested a fraction of the money they have in Google Glass, then I'm convinced they could bring these kind of glasses to the world, benefitting hundreds of millions, And just perhaps, by incorporating Glass-like functionality along for the ride, they could bring Glass to the masses.

Filed under: Product-Ideas No Comments
12Oct/140

The inevitable evolution from wearables to embedables

The inevitable evolution from wearables to embedables is at once both exciting and horrifying.

Let's think about bluetooth headsets. They are already becoming smaller, and will soon be invisible.

I believe that bluetooth headsets will miniaturize to the point of being so tiny they will be embedded subdermally, perhaps behind your ear. We'll solve the battery issues through using the body's own heat, or through body motion.

What will this give us? Only telepathy. You'll be able to communicate mind-to-mind with anyone on the planet through this device that is part of you, initially by voicing words sub-vocally, but perhaps one day through splicing directly into nerves.

It is as exciting as it is inevitable.

What is also inevitable is a despotic regime somewhere will use such capabilities to pipe their propaganda directly to their citizens minds. Can you imagine, from birth, having this incessant stream of brainwashing beamed directly to your brain? Its horrifying.

So, along with the best case scenarios with dreaming of new technologies, let's also think of the nightmare worst-case scenarios, and make sure we do what we can to mitigate them. In this case, let's start with a physical off-switch.

Filed under: Product-Ideas No Comments