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Showing posts from December, 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…

To iPod or not to iPod

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I have been thinking on buying a new iPod. I've got a 4GB mini iPod since 2004. It works nicely and as my iBook it has been locked into my wife's gravity field. I have to admit that both devices come with a high WAF value (you know WAF, don't you?).

The only problem with [her] iPod is that it cannot hold all the music we have. However it seems that Apple is not offering any education discount on iPod at the moment. Prices have not changed for quite a while and I find the thing a bit pricey. I've been a happy Creative customer and all our outher MP3 players at home are from them. They have a 30GB Zen Video player that seems to offer better image quality than iPod but it is 5mm thicker (though it has a mic for audio recording and an emdedded FM receiver too). Price is the same as 30GB Ipod ($249). And ... the Creative has host-mode USB (it means you can connect it to your digital camera to transfer the photos to the unit HD without using a computer).

We will need to wait …

Two in one

Both Sigmatek's dvbx200 and Woxter's xvid 675 dvbt seem to be the same: A DivX player plus a DVB-T receiver. As they look the same, they are likely made by the same chinese OEM manufacturer and just branded different. I've tested a Sigmatek unit and I've found it delivers what it promises:
It plays back DivX files from either a DVD or a USB memory stick. It also plays back the photos of your camera (provided it uses SD format) using the built in slot. It also seems a good quality DVB-T receiver.It includes an ok remote control. Don't get me wrong, this is not a top of the line product, but you hardly can beat it at that price range (around $80).

Another Genius Tablet

I mentioned before one portable tablet from Genuis (the G-Note 5000) that can also be attached to the computer to be used as a regular tablet. I'm quite happy about it but unfortunately it does not have pressusure sensitivity (two is not enough for some applications).

Wacom is the brand name drawing tablets. The problem is that Wacom tablets are quite expensive too. The main advantage of Wacom is that they pointer they use requires no battery. Other brands, however, although they have cheaper units, require a battery inside the tablet stylus.

I think I can handle the extra weight so I have bought a Genius G-Pen 4500 for around $35. Besides I am also getting a small mouse I can use in the same tablet space.

The included software worked Ok in Windows XP with The Gimp but not with Inkscape. The OS X driver seems to work only so an so (it might be it requires a good amount of processing power and my iBook is not that fast, I am not sure).

Linux was a no go. Although the G-Note worked with…

GPS navigation: Navigator 4000

The holiday season is approaching fast and so is my birthday. After having a couple of incidents of not finding my way driving the car recently, I decided it might be ok to get one of these GPS tiny toys. As I am not PDA kind of person I was thinking on a device that contains all what you need.

Some other people might want to get a Bluetooth-based GPS antenna to be (wirelessly) connected to their PDA that, equipped with the right software, will do the work of a stand-alone navigator.

As usual, there are just too many choices to make and many different brands and prices. To make things worse you learn that the unit could also include a Bluetooth hands-free adaptor or a TMC receiver. But wait, what's TMC? I'd never heard of that before. Then you learn that the business is somehow selling you extra maps too (or new versions of the ones you already have). After all, a GPS navigator is as good as the maps it is based on.

Can your GPS navigator play MP3 files or movies? Damn, this i…