Posted by & filed under Open-source, Web Development. 63 views

For some reason there was an anomaly in one of our metric last night and it was ruining a lot of our graphs readability. The data was correct and we are looking into the issue but it was anomalous and so high that it was hurting mean, mean_90, etc.

So I needed to find a way to overwrite existing data in Graphite. You cannot remove datapoints in Graphite but you can overwrite the data manually if you know the time stamp:

echo 'stats.timers.browser.timedPageRender.circus.accounting.rendered.mean 14000 1409268080' | nc p2-graphite.ad.prodcc.net 2003

If you’ve got a few bad data-points and you used statsd to gather timer data for example and as such it spans accross a few different metrics (median, std, mean, mean_90, …), I wrote a quick commmand line application to overwrite data over a give threshold for a span of time. You’ll find it in this gist but proceed with caution. Look at and understand the different constants, check the time range (I didn’t put constants for that). Here there be dragons. You’ve been warned!

Posted by & filed under Electronics. 3,315 views

HiTec 44167 X4 AC Plus 4-Port AC/DC Multi-Charger

After buying and borrowing a few chargers, I realized I didn’t want to ever have to upgrade (in a multirotor/plane scenario) my next LiPO battery charger, didn’t want a cheaply made and potentially dangerous Chinese clone and wanted something solid I could take to the field and power from my car battery

So, what is the best LiPo charger?

My advice would be to go with the HiTec 44167 X4 AC Plus 4-Port AC/DC Multi-Charger. This checked all the checkboxes for me and for just a bit more money seemed vastly superior than the alternatives.

I use this connected to an AC outlet at home and while flying connected to my car battery. It charges four batteries at a time and is built like a tank.

Each port of the X4 AC Plus can handle up to a 6S Lithium, LIPO pack, 15 NiCd/NiMH cells or 6-12 volt lead acid batteries. Four individual balancing ports eliminate the need for a separate balancer when charging Lithium batteries. Its twin fan cooling system with an internal sensor for controlling fan speed provides the utmost in efficiency and safety. It’ll discharge battery, charge them for use or for storage, balancing the different cells effectively.

Why shouldn’t I get a cheap LiPo battery charger?

I know many will say it’s out of your budget, but in all honesty it really is something that you shouldn’t scrimp on for so many reasons, the main one being safety. This charger has already been adopted by many, you really want to just be able to buy a unit that does everything adequately and safely and be done with it and not have to upgrade again.

Not all chargers are equal, and cheap Chinese crap from Hobby King should be avoided. Get a charger from a known brand that has a good reputation such as Hitec.

How fast can I charge LiPo batteries?

How long it should take you to charge a 4000 mah pack ? Well you should have something that is capable of matching the capacity in one hour, so something that can charge at 4000 mah, also referred to as 1C. Although you can charge some packs quicker I don’t recommend it and obviously the cost of a charger that is capable of that will go up considerably.

If you want a charger that is going to charge your packs at 1C it’s not going to be a super-cheap item, and the ones that can and are cheap I would tend to avoid. You really want a digital charger that will tell you what you are currently charging at, what the internal resistance of your pack is, should have excellent balancing capability and also allows you to charge/discharge for storage.

This is it.

P.S. Note that you’ll want to get three XT60 Charge Cable (one comes in the box) to charge four batteries simultaneously Balance

P.S.2
Good and cheaper (but not cheaply made) alternatives exist, the HiTec 44165 Plus Single Charger which charges one battery on AC or car battery and the HiTec 44169 4 Port Multi-Chemistry Charger which will charge 4 simultaneously but only on an AC outlet.

Posted by & filed under Kindle, Web Development. 5,495 views

I have now made available an RSS feed for the audio book deal that Audible publishes every day: Audible Daily Deal RSS feed (http://feeds.feedburner.com/AudibleUsDailyDeal).

I have also added it to the US iOS & Android Amazon Kindle Deals of the Day applications that I built. I know that they’re not technically Kindle deals but I thought the same audience would be interested in them.

Posted by & filed under Electronics, Video. 717 views

And your shows are no longer downloading…

I had that issue with my Tivo Premiere XL4 and I fixed it by going through the Guided Setup twice (Settings/Help/Reset or Rester/Guided Setup), the first time with a bogus zip code(90210)/Provider and after that with my actual zip code and cable provider. That caused the Tivo to just reset its guide completely and all was well.

Posted by & filed under iPhone, Open-source, Web Development. 1,136 views

After much trial & error, I figured out how to do this on iOS 6, PhoneGap/Cordova 2.5.0 and jQuery 1.9.1

  • OpenAllWhitelistURLsInWebView doesn’t matter. Setting it to true, false or omitting it doesn’t seem to have any bearing on the result.
  • I set a target of _system on the href, like so:
    <a target="_system" href="http://rads.stackoverflow.com/amzn/click/B009CZICQ8">

  • I then call:

    $("a[target='_system']").click(function(event) {
    event.preventDefault();
    window.open($(this).attr("href"), "_system");
    });

And it just works! On iPad & iPhones.

Posted by & filed under Android, Gadget, iPhone, Personal, Product Review. 2,216 views

Best iPhone car mountLast year, I got a Parrot AR.Drone 2.0. It was fun but limited in many ways. While controlling the helicopter via iPhone or iPad was fun at first, it just wasn’t as reliable and precise as one would want. The helicopter was a fun toy but limited in many ways, hard to repair (you’ll crash it) and quite fragile. So a few weeks ago, I purchased a DJI Phantom, a ready to fly, remote controlled quacopter. The Phantom is a completely different bird, and it should be at more than twice the price. Here is my product review.

Pros

Ready-to-Fly (no soldering), very little assembly required.
Most multi rotors – quadcopters are diy builds
It’s addictive!
Flying those is a lot of fun. It’s easy but not too much so, it’s still challenging especially as you start flying high and far, above and around obstacles and start taking videos
Integrated remote control unit designed for the phantom
much more precise and easy to use than a smartphone or tablet touch screen
Easy to fly, Stable, yet agile performance, GPS integration
Learning curve isn’t steep. Start in GPS mode and Home Lock, then take the training wheels off.
Failsafe mode
When the controller is turned off, loses connection or when triggered manually (an optional configuration on the controller), the Quadcopter will hover for a short while, rise (or lower) to 60ft (20m), come back to the take off location, hover a short while then land.

GPS, Attitude or Manual mode
GPS mode will maintain a hover stationary position when no input is given, Altitude will keep the quadcopter at a given attitude but the copter can drift. Manual mode is…manual.
Intelligent Orientation Control (IOC) – Home Lock & Course Lock
Often, when you fly a quadcopter far away from you you cannot tell what direction the nose is pointing.
When in home lock mode forward and back control movements are relative to you the pilot. Left stick movement will make the phantom to fly in a radius around you. Think of it as telling to phantom to draw a circle like a compass since you are telling it to go left or right relative to you as the center point.

Pretty essential.

Cons

  • At $679, it is quite a bit more expensive than the AR.Drone 2.0 – but it’s a very serious piece of equipment
  • With no payload, you’ll be able to fly for 12 minutes or so (which is actually longer than it seems), with a GoPro 3, it’ll be reduced to 9-10 minutes so you might want to grab a couple of additional OEM DJI batteries or slightly longer lasting batteries for longer play time
  • The QuadCopter doesn’t include a video recording device and is designed to work well with the GoPro 3 (mount included). So you’ll need to buy a GoPro 3 (White, Silver or Black) if you want to record your flights (and you want to)

DJI Phantom mini-FAQ

I can’t find any manual in the box?
There is no manual in the DJI Phanthom box (there wasn’t in mine). One should refer to the Quick Start, Advanced, Naza-M, Battery & Charger manuals available on the DJI web site.
The battery has two connectors, should they both be connected to the charger?
The battery is a 3 cell, or “3s” 3.7 volts each for a total of 11.1 volts. The little adapter, is called the “balance lead”,
and is used when charging the battery, to make sure all cells have the same amount of charge. Yes, you do have to plug
it into the charger when charging the battery.
What’s essential to know for my first flight?
  • Charge your battery
  • Attach your blades (being careful of the rotation direction for each
  • Attach the landing pads, connecting the compass, using tape to secure compass & antenna
  • Insert 4 AA in the controller
  • Turn on the controller, make sure the throttle, left controller, is pulled all the way back, towards you
  • Put the battery into the Quadcopter to turn it on
  • Wait for GPS acquisition
  • Calibrate the compass
  • Start the motors by pulling the left & right joystick towards you then giving it a little throttle (left controller) by pulling it slowly away from you.
  • FLY your Quadcopter
  • After landing, remove the battery
  • Turn off the controller
GoPro 3 (Black) moves around a lot in the DJI mount, am I doing it wrong?
Strangely, the GoPro mount that’s included works best for older GoPros. Use a bit of foam to fit a GoPro Hero 3, use the waterproof casing or use the GoPro Frame Mount which is the lightest and most secure way to hold a Hero 3 for the Phantom.

First flight

This was my first flight with a camera, it shows how high and how far the Phantom can go

YouTube Preview Image

Posted by & filed under Android, Gadget, iPhone, Product Review. 16,663 views

Best iPhone car mountAfter buying a few duds, I finally found a good iPhone windshield/dashboard car mount.

When you insert your phone into the iOttie HLCRIO102 One Touch Windshield Dashboard Universal Car Mount Holder, a push button gets depressed which will cause small plastic jaws to secure the phone in place. It works well most phone cases. A couple of side buttons will release the phone. The mount rotates easily from portrait to landscape and the foot sticks very well thanks to a vacuum lever.

Beyond the iPhone 4 and iPhone 5, it seems it’ll work with iPhone, Android & Blackberry phones:

  • iPhone 3G, 3GS, 4S
  • Samsung Galaxy S3/S2
  • HTC One/8X/8S
  • Nokia Lumia 925/928/920
  • Blackberry Q10 & Z10
  • LG Optimus G/Nexus 4
  • Motorola Droid RAZR/MAXX/HD

A larger version, the iOttie HLCRIO101 One-Touch XL will work with Phablets and large phones:

  • Samsung Galaxy S4, Galaxy Note2, Galaxy Note, Galaxy Mega5.8
  • HTC DROID DNA

Posted by & filed under Kindle, Mobile. 950 views

After making the Canada, Spain and Italy versions of the Kindle Deals of the Day Android apps, I thought I’d gives you guys some RSS feeds for the same:

RSS feed for Amazon.ca Kindle Daily Deal (Canada)

RSS feed for Amazon.it Offerta Lampo Kindle (Italy)

RSS feed for Amazon.es Kindle Flash (Spain)

Posted by & filed under Android, Web Site. 1,115 views

After the US, UK, Italy, Spain & France versions, I created an Android Application to monitor the Amazon.de Kindle Deal of the Day / Kindle-Deal des Tages and a:

RSS feed for Amazon.de Kindle-Deal des Tages