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Showing posts from October, 2006

Moving code from ESP8266 to ESP32

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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…

eBay scams

I was looking for a new 12x zoom camera with image stabilization. I turned to eBay to see if I could find better deals and, specially, more offer than you might get from local retailers. I settled with a reputed seller from Hong Kong, and I paid almost the same as the list price from a local seller but the deal included an extra battery and a 1GB SD memory.

In the process of looking for a deal on eBay, I detected numerous problems on listings of various products (i.e: digital cameras and USB flash storage). I reported my findings to the Spanish branch of eBay but to date, four days later, I've got no answer from them. I did the same thing to eBay.com Safe Harbor and I've got an automated reply, but some hours later I could see that some of the users accounts had been cancelled.

After searching a bit on the 'net I can see that a common scam is to sell fake flash storage (either USB or SD or any other format). The trick is that the storage actually works, but it only contains …

Ubuntu 6.06 LTS five months later

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After some months of use I think I can provide you my impressions on how this Ubuntu thing behaves.

I used to be a SuSE Linux user since 8.0 and then, after 10.0 I had several minor issues with some hardware. I decided to give Ubuntu a go and since then I have succesfully migrated six different systems desktops to it. I have also installed more than four other copies on several relatives computers. The net result is all of them are happily running.

I have been consistenlty using Ubuntu on a daily basis since mid-June and I'm very happy with the result. I was familiar with KDE and I am now using Gnome and I cannot complain either. It just works, though I am sure some of the days I needed to pull one or two tricks out of the many on-line forums about Ubuntu (like getting 3D acceleration on some ATI cards). If you use Ubuntu Dapper Drake I can recommend you this site.
My advice is: try it out. If you do not like you can get a refund. Till now it Ubuntu is the only distro you can get the…

Genius G-Note 5000

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Some days ago I saw this nice gadget on the website of a distributor. I thought it might be a good idea: A notepad you take with you, you write as many pages as you want and, when you are back home you can download all your handwritten text or drawings.

Of course you can do this with a cheap scanner without having to recourse to buying any new hardware (provided you already own an scanner). However, what I was looking for when I learned about this product was a tablet for drawing.

The Genius G-Note series does both: You can use it off-line to write more than 100 pages in the built-in 32MB of flash memory and it can also be used online as a mouse substitute (or companion). I feel much more comfortable when writing and drawing with a pen than with a mouse.

The unit came with some Windows software which was ok. Without any software the tablet looks like a USB flash drive to your system where each page drawn shows as a different file. Filenames are numbered (i.e. BK-01-001.DNT, BK-01-002…

Free software is not only for geeks

I've recently learned that the software taught at the Fine Arts School at the university I am with is based on three comercial programs: Adobe's Photoshop, Macromedia's Freehand and Microsoft's PowerPoint. The three are nice pieces of software in my opinion and I am aware they are used by many companies.
What troubles me is that students are left either bankrupt (Photoshop €1.042, Freehand €520 and PowerPoint €338, which totals €1.900) or having to get a pirate copy of the software.
With all due respect I think they could teach the same concepts (which I guess are the very basics as it is an undergraduate course) using the free counterparts The GIMP, Inkscape and OpenOffice's Impress. These programs have a similar functionality (ok, maybe just 90% of the others features) but are available for free for almost ANY platform, including Windows, Linux and Apple's OS X.

For those unfamiliar with the software world, let me put an example: If we compare the software indu…