Chris Novello chrisnovello

How to flash Watchman firmware to a Crazyradio PA dongle

This is a quick guide on how to flash the Watchman firmware (SteamVR tracking dongle) onto Crazyradio PA dongle.

CAUTION: It seems like the dongles end up with really short range, they work technically but is not really all that usable at this time.

Requirements

A Crazyradio PA dongle
A Linux device (Raspberry PI is excellent for this, but any computer running Linux will do)
The "SteamVR HDK" for the Firmware binary
AFAIK no one can legally redistribute this, you will have to register for a SteamVR Tracking License to get this.

Web Technologies Only

AR.js
clmtrackr
OpenCV.js
TensorFlow.js, you can build your own computer vision technology.
ML5.js — similar goal to TensorFlow.js, build your own ML to recognize patterns, including computer vision!
Tracking.js — a component based CV tracking system written in JS, you can write functions that define what features you're looking for

Web + Native Technology

Three.ar.js

better caches with rethinkdb

TL;DR - smelly software engineer discusses using rethinkdb changefeeds for building caches, breaks hearts, shaves the cheerleader, shaves the world.

Let's talk about caches.

Imagine that you build UIs for an ecommerce company, possibly in a fancy office with free coffee and whatnot. You've just been asked to build a way for the marketing / sales folks to change landing pages whenever they're running campaigns. After a number of angry discussions involving the ux team about what they can and cannot change, you settle on a 'document' format for these pages. It could be json describing a tree of widgets of banners and carousels, or html, or yaml, or whatever. Maybe you also invent a dsl that marks out parts of the document as dynamic, based on request parameters or something. I dunno, I'm not your boss. You build a little ui over the weekend (with react? maybe!) that lets these folks login, drag and drop their banners, maybe upload an image or two, and save to database.

Yo

Theory of Building Caffe on OS X

Introduction

Our goal is to run python -c "import caffe" without crashing. For anyone who doesn't spend most of their time with build systems, getting to this point can be extremely difficult on OS X. Instead of providing a list of steps to follow, I'll try to explain why each step happens.

This page has OS X specific install instructions.

I assume:

Firefox bullshit removal

Updated: Just use qutebrowser (and disable javascript). The web is done for.

Thoughts on Swift 2 Errors

When Swift was first announced, I was gratified to see that one of the (few) philosophies that it shared with Objective-C was that exceptions should not be used for control flow, only for highlighting fatal programming errors at development time.

So it came as a surprise to me when Swift 2 brought (What appeared to be) traditional exception handling to the language.

Similarly surprised were the functional Swift programmers, who had put their faith in the Haskell-style approach to error handling, where every function returns an enum (or monad, if you like) containing either a valid result or an error. This seemed like a natural fit for Swift, so why did Apple instead opt for a solution originally designed for clumsy imperative languages?

I'm going to cover three things in this post:

	CREATE OR REPLACE FUNCTION notify_trigger() RETURNS trigger AS $$
	DECLARE
	channel_name varchar DEFAULT (TG_TABLE_NAME \|\| '_changes');
	BEGIN
	IF TG_OP = 'INSERT' THEN
	PERFORM pg_notify(channel_name, '{"id": "' \|\| NEW.id \|\| '"}');
	RETURN NEW;
	END IF;
	IF TG_OP = 'DELETE' THEN
	PERFORM pg_notify(channel_name, '{"id": "' \|\| OLD.id \|\| '"}');

	[
	{
	"action": {
	"type": "block"
	},
	"trigger": {
	"url-filter": ".*",
	"resource-type": ["script"],
	"load-type": ["third-party"],
	"if-domain": ["imore.com"]

	/*

	Erica Sadun, http://ericasadun.com
	GameplayKit Available 10.11, iOS 9

	*/

	import Foundation
	import GameplayKit // only available on OS X 10.11, iOS 9