Category Archives: technology

Wifi in my car: proof of concept

Some drivers love fancy chrome wheel rims, some add a huge wing spoiler on their car, or fuzzy dice hanging from their rear-view mirror. Me, when I bought my new car, I decided that I wanted a Wifi network in my car. So that any passenger with a laptop/iPod could read his email. And I imagined driving to distant holiday locations while my passenger where watching movies streamed from a NAS disk built into the car.

This weekend I finished episode one: Internet in the car. I used the following components:

The important details here are:

  • The Huawei stick is compatible with the TP-Link router.
  • The Huawei stick can be configured with ‘Save my PIN’, so that when it starts up, it connects to the 3G network without any manual intervention.
  • The TP-Link router runs on 12V DC (which is what a car has)

For the rest, the exercise was quite straight-forward: I configured the Huawei stick on my laptop with the right PIN code, popped it in myTP-Link router, configured the right 3G settings for Telenet (see here). Then I took an old 12V power transformer, chopped off the connector and linked it up to an old car cigarette lighter type of plug (sometimes it’s good to have an archive of obsolete cables and power supplies). I then hid the router under the base plate of my trunk, where there is also the battery (the BMW X1 stores the battery in the back, where you would normally have the spare tyre). I switch on the car and 20 seconds later, I have a Wifi network “OnTheRoadAgain” that is connected to the Internet. Proof of concept is OK!

The next step now is to add a (Synology) NAS, which also runs on 12V, and hook up my iPad to the car Wifi to view my collection of backed-up DVDs from that disk. And maybe run some extra programs (e.g. MRTG for monitoring) on that NAS. To be continued!

Status page for telecom/internet providers

My mobile provider Telenet had a partial outage today. Sometimes calls would go though, sometimes not. Same things with SMS and 3G. I wanted to check if there was a page I could check to see if it was just for me, just for that location on globally in Belgium. You know, a proper status page like Google and Apple have. Or in Belgium, like Combell. It appears Telenet has one, but it’s for the Internet division. They also have a Twitter account that is well followed up. How does this compare to the other providers? Here is an overview of who offers what:

Mobile Telephony/Data

Belgacom Proximus

Mobistar

Telenet (on Mobistar network)

Base (part of KPN)

Mobile Vikings (on Base network)

Broadband Internet

Belgacom

Telenet

Scarlet (part of Belgacom)

Kudos to http://www.ionasj.com/welk-netwerk-voorziet-de-beste-dekking/

Idea: email as a platform

146354021_1c0f548dfe_m[1]Something has been bothering me for a while. I have a colleague that needs to post some files on a site every week, and she needs to do it via FTP. FTP is ‘geeky’ for most people. Their PC does not come with an FTP program installed, they never need it for daily web usage and they’re not sure how it is different from email/web upload. I ended up installing Filezilla for her and she manages, but it would be so much easier if I could tell her: just email it to XYZ@example.com and it will arrive on that FTP server. Sending email, everyone can do.

Another issue I had is that I would like to offer a service (that involves audio manipulation of WAV files) and I would like people to send an email with the file attached and I send back the result. In both cases, the problem is the same: email now arrives in a mailbox and is expected to be handled manually. I would like a platform service: I pay for the usage of an email address, and every mail that arrives there triggers a number of actions that are automatic.

Not just a service, a platform

Of course I’m not the first one to think of this. Flickr allows for posting pictures via email (I use that a lot), you can send your blog posts via email with Tumblr, Posterous and even WordPress. Customer support services allow auto-responding on incoming emails with suggestions for resolutions. It’s just that all these services are specific to the provider. To do it, you have either poll for incoming email (check your POP3 box every N minutes) or build/configure an SMTP server that handles incoming email. If you’ve ever encountered the black magic involved in configuring a sendmail/postfix/qmail server, you know that’s not for everyone. Me as a web developer/hacker, I want to configure: mails sent to XYZ@example.com are posted to my web page with the email body, sender, attachments (as URL), or published via a private RSS feed, and that’s how I get them into my workflow.

The funny thing is that a much more limited communication method, SMS/texting, has these platforms. There’s Twilio, Fortumo, Tropo, that allow you to receive text messages and make them trigger things. The US providers even allow for setting up automated IVR (Interactive Voice Response – a.k.a. “Press 1 for …”) application through these services.

So, the idea

So what could this platform look like?

  • I register for the service and I get the prefix ACME
  • I then start defining my services: acme.upload@example.com, acme.support@example.com, acme.register@example.com
  • I configure acme.upload to save attachments to an FTP server and send a confirmation email.
  • I configure acme.support to send a confirmation email with a unique number and forward the email with this unique number in the subject. Also, I get an SMS.
  • I configure acme.register to take .XLS files, convert them to TEXT and post them to a web service I have created. I also get the sent emails in an RSS feed.
  • I now create my ‘public’ addresses: upload@acme.com / support@acme.com / register@acme.com and forward these to the email addresses I created above.
  • I get daily/weekly reporting, spam detection, and unlimited scaling.

Do anything like this exist?

Focal length for the common man: “portrait distance”

I remember that before I started photography on a serious level, I had some understanding of shutter speed, but none of aperture and focal length. Even when I read what they meant, I still couldn’t ‘picture’ it, had no feeling for the numbers. Let’s leave ‘aperture’ for another time and just concentrate for now on the concept of “focal length”

First of all, the focal length of a lens is not the same as the actual physical length of the lens. Yes, 200mm and 300mm lenses (telephoto lenses) tend to be longer, but they’re not exactly 200mm and 300mm long. For instance, the Sigma 55-200mm F4-5.6 DC HSM is 85mm (3.3″) long,  while the 70-200mm F2.8 II EX DG lens is 184mm (7.2″). Same maximal focal length, but more than twice as long.

So what is focal length? I could explain that it is “the distance from the center of the lens to the principal foci (or focal points) of the lens“, but that wouldn’t make it more comprehensible, would it? Well, I read through the theory, with tangens of the viewing angle and stuff, and I think I understand it (I’m an engineer, I actually like trigoniometry). A 200mm lens gives a viewing angle of 12° on the diagonal. Still not clear? That’s when I thought: let’s invent something more tangible: the “portrait distance“. Say you need a surface of about 72cm x 48cm (28″ x 18″) to make a portrait of a person (not just a headshot, but with some torso on it too). See some examples below:

Vriendschap foto's voor Erfgoeddag Sandy @ Chaff Brussels Tango Festival - Day 1 ¿Que? Fado & Tango - Dirk

Well, the distance between the camera and the person you’re making the portrait of, will be +- 20 times the focal length.

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