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Showing posts from December, 2004

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…

Of foldable bikes

I live in a flat in a six storey building close to the campuses of two universities. As parking and traffic really suck around here I decided to get a bike.

But lacking of parking place the obvious choice was to get the bike back home with me. You just cannot park it in the streets if you want to keep it for a long time. The problem was, then, to get the bike from the street to my flat.

I've seen some people tilting bikes front-wheel upwards so they can fit it in the elevator but it didn't seem to me very convenient, and then you'll need some real estate inside your home anyway.

I've learned about several brands making foldable bikes (Dahon, R-M, Brompton). Minutes later I've learned too that this stuff was expensive. I finally settled with a Dahon's Vitesse 3D for 425 Euros. It was a trade-off (and one of the less expensive alternatives) between folded volume, price and comfortable ride. I'm quite happy about the bike although I still think it could be ch…

New article

January 2005 issue of Circuit Cellar Ink magazine contains my article titled "Build a Digital Video Recorder" with some clues about doing exactly this.

Some days ago I was told some the systems that were cloned using G4U software seemed to have a lousy filesystem now. As the problem seems to be repeatable, it looks that the cloning process was not flawless for reasons yet to be determined (I'm in the process of finding out).

It didn't take long before I have to use it

My kid's computer harddisk was dying last week. It booted up and it worked but sometimes after a clean shutdown CHKDSK was triggered on next boot (they use XP pro). The check was reporting some damaged sectors and I knew a replacement was due. I better do it now or I will have to reinstall everything from scratch.

I went to the shop and I've got a new 160GB Maxtor drive. But, as usual, things were not exactly smooth: Old drive was a 40GB IBM drive with a single FAT32 partition. I wanted to get a bigger partition as the new drive was larger and I wanted to copy the old winxp system onto the new drive.

Unfortunaltely, due to some defective clusters, G4U software stopped after copying only 6 GB and the result disk was unusable. G4L also failed because of the same reason. I borrow a copy of Ghost 2003 for DOS just to discover that I needed a boot floppy to run it and that my floppy drive was not working and full of dust. I got rid of the dust from the floppy and it eventually wor…

Some interesting tools

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My last project dealt wih the use of 1U rack-mounted PCs. Once the software was ready for deployment I needed to find an easy way to get the operating system and applications loaded onto the systems and I was looking for an easy and fast way of doing it.

The units I am using are manufactured by Supermicro and they have no floppy or CD-ROM but are equipped with dual Gigabit Ethernet ports and USB 2.0. While booting the system up from a USB CD-ROM was possible this was leaving me with the task of manually configuring each unit.

I've used in the past Symantec's Ghost software for harddisk clonning and I've found it quite useful. But to be able to use it in this case I would need to boot these computers out of a floppy disk or specially crafted CD-ROM that I don't have ready. On the other hand, a Ghost license will need to be purchased.

Browsing around I've found a couple of projects G4U (Ghost for Unix) and G4L (Ghost for Linux) that offer you a ready to burn ISO imag…