Showing posts from October, 2007

Moving code from ESP8266 to ESP32

A while ago I made a mashup of Dan Royer's code CNC 2 Axis Demo with my own code for trapezoidal motion stepper and servo control for ESP8266.

I assumed porting the code to the ESP32 would be trivial, and that was true for the most part: changes like library name being Wifi.h instead of Wifi8266.h were not a problem. UDP now does not like multicharacter writes but you can use print instead. So far so good.

However, when it came to the interrupt code I was stuck with the stepper interrupt causing an exception sometimes. And to make things weirder, the servo interrupt worked flawlessly (both of them had the IRAM_ATTR directive if you ask me).

Going little by little, I could narrow down the culprit to a floating point operation during the interrupt, that would cause problems sometimes but not always. Browsing around I found this post. Where the solution was simple: do not use floats within the interrupt routines but doubles. The reason was the float calculation would be performed by…

Removing DRM from WMV files

Did you ever wanted to play a file on a different device but you were prevented to do so because the file you bought had some nasty DRM inside?

Well, I did and I wanted to do something about it. There is a tool that seems to work nicely for this purpose and it does not involves cracking the DRM system. It is tunebite software. It somehow reminds me the idea of Total Recorder but now it does work with videos too.

The idea is quite simple: If you can play it you can record on-the-fly from your own computer. I guess it is easier to say than to do it. But this company seems to have done a pretty good job.

They claim doing this is not illegal but I cannot provide you legal advice. For me it did the work of enabling my wife watching a DRM-ed video on her Creative Vision:M, which by the way it is a better video "iPod" than Apple's.

Merging Arduino and Xbee

There are many open source projects out there. Many of you are familiar with the concept of open source software, where the source code is made available. Not so common is the idea of open-source hardware. What is the idea here? You get the full details of the hardware and firmware as if it were just the code of an open source software project. It is about extending the openness of a project to the hardware and firmware levels.

Arduino is one of these open-source hardware projects. It is a family of small printed circuit boards powered by Atmel micro-controllers that can be programed. You develop the code for these micro-controllers using an Integrated Development Environment (IDE) also provided on the project's web-page, available for Windows, Linux or OSX. The IDE is based on Processing IDE I covered a while ago and the programming language is based on Wiring language. The goal is to make user life easier as the development is aimed to artists more than to engineers.

The micro-con…

Photo slideshows

Digital photography brings yet another way to annoy friends and relatives. Digital photogtraphy is convenient, and you do not have to buy or develop film, so you may end up, like me, taking (and keeping) many shots that are not that great.

Thousands of pictures pile up on your hard drive but they are not in a format you can easily share with your grandma (unless she is Internet proficient). Two online services I have found quite useful are flickr and Google's Picasa. They make easy for you to share your photos even when you are on the go.

However, if you want to create something oriented for people who at most are capable of playing a DVD then you need other tools. Some DVD burning programs can help you creating a simple slideshow of your photos. However my experience is that just a sequence of pictures without a soundtrack is not something people are going to enjoy.

Another problem is that even if you have sound, the pictures without any motion look boring and uninteresting most of …

Kensington Expert Mouse

Contrary to what the name may suggest this device is not a mouse but a trackball. At around $100 it is an expensive alternative to traditional mice. Kensington trackballs have been around for more than 15 years and I have read good things about them.

I decided to judge by myself and I bought one unit. The bottom line is that except the annoying noise and feel of the scroll ring the device is quite nice. The optical tracking is hopefully more precise and less sensitive to dirt than older mechanical systems.

I have contacted Kensington customer support to report the problem, but given what I have read on the net it seems to be a common complaint from users. I have not yet heard from Kensington but I have thought you may want to "hear" and feel it by yourself before buying one unit.

Joost 1.0 beta is now available

I've tried both versions, windows and osx, and they seem to work ok. The new era of P2P TV is here for you to decide whether it will stay or not. Joost image and sound quality are quite ok. Service is now open to everybody, you may want to give it a try.

Good-bye Mailinator?

I tried to use service today unsuccessfully. It seems the popular passwordless free webmail service is not available now (being passwordless means that you should not use it for any private messages as anybody might have access to your messages if they figure out your mailbox name).

For several years, Mailinator was a useful allied for those not willing to give up their real email address when registering for a service or download.

They seem to have a blog. And nothing about shutting down the system is ever mentioned. So hopefully is just a technical problem they are experiencing as the domain name is paid for till 2011 by Mailinator's creator Paul Tyma. Pinging the server works, but the system rejects any http connection attempt.

Anyway, fear not as there are different interesting alternatives.

Update: They are back on-line!!

Another new iMac

I have been fascinated with the idea of a silent computer and the new Apple iMac captured my attention when they created the new aluminum line.

Last time I bought a computer from Apple it ended up being used mostly by my wife. For this problem not to happen again I've just bought her a new iMac!. I am allowed to use it from time to time (mostly to install new software).

After a few hours of using the system I am more than happy with the looks, the clutter-free desktop and the silent operation (I guess that after several minutes of heavy load you will start listening some noise but this just has not happened yet). I've read it has three fans inside.

The main complain is that the unit is not user serviceable (say goodbye to upgrade your hard disk). However everything I've tried just worked out of the box, no problem at all. I only needed to look the documentation to learn how to suspend the system (press play 3 seconds on the remote or the power button or select suspend in the …