Paraphrasing the movie Full Metal Jacket, this is my calculator. There are many like it, but this one is mine. It is my life. I must master it as I must master my life. Without me, my calculator is useless. Without my calculator, I am useless.

A real electroacoustic machine! 😉

Or at least it was that way during my university years. I used to know every funtionality and button of this Casio fx-991MS calculator. What’s more, I used to know what I was doing during the calculation process. Now, I see it and it looks like an old Chinese manuscript to me. Of course I recognize every term on it, but in the end, I only use the +, – and = buttons. It’s a pitty all these forgotten and unusued maths in my life. I should start using it againg, for real.

Build your own video card

As a former image and sound engineer student, I wish I had an electronics teacher as Ben Eater. You can follow his explanations even with not knowledge at all (well, a little bit in maths). In this video he is creating a fully functional computer video card. Amazing. It could had been a good final project for my degree.

Tales from the Lunar Guidance Computer

In Tales from the Lunar Guidance Computer, Don Eyles, a software engineer during the Apollo lunar missions and developer of several programs for the computer of the Lunar Module, does a very detailed description of that computer and its i/os, the real time system used and also the efforts made to solve some bugs and replicate errors. Truly interesting if you love computers and astronautics.

“I’ve written computer programs while I was stoned which have turned out to be pretty good programs.”, Don Eyles at Extra! Weird-Looking Freak Saves Apollo 14!


Several months ago, in my spare time and as a gift to a friend, I started a mod to a NES gamepad. Last week, finally, I wrapped it up.

The Nesduino ( yes, a very original name 😉 ) includes four main functionalities:

  • A clock visualizer with four modes
  • Three configurable alarms with different tunes to choose (Mario Bros, Indiana Jones, Star Wars and Legend Of Zelda)
  • Five games (Snake, Flappy Bird, Cat&Mice, Simon and Dice)
  • Ten background animations

The electronics consist in a Wemos D1 Mini, a small speaker, a red 8×8 dotted led matrix and the original NES pcb. Besides, the device is powered by USB. If you want to take a look to the code, here it is.

It’s been a very enjoyable project and also I’ve learned a lot along the way, specially about game development. I only miss the possibility to use the gamepad with the computer via HID , but as far as I know,  the Wemos D1 doesn’t support it.

And if you’re a retro lover like me, all this modifications worth just to save an old gamepad and give it a whole new life.

Long live the dot matrix printers!!!

Following my last trend of trying to reuse things, I’ve purchased a dot matrix printer, an Epson LQ-300+II. Not too old because at least it has USB 1.0, but, you know, is one of these old school printers that make those characteristics crink and clank sounds. I’ve always wanted to have one, and just for 22€ (4,4Kg of shipping, two cords and a brand new ribbon cartridge included), I thought it was a great deal!

Epson LQ300+II

First time I saw one as a child was at the Public Treasury Office in Badajoz with my father. I’ll never forget the continuous feed paper folded in piles and the noisy (not to mention smoked) ambient. I also remember that courier dotted grey “a” letter, symptom of running out of ink. There’s something in that printed letter that got my attention. My guess is, at that precise moment, I discovered they were using needles and ribbons, like my father’s Olivetti typewriter. Simple but effective!

After receiving the printer and testing it, I opened the case and perform a full clean. It’s incredible how analogue these printers are. You can almost full dismantled one just pushing/pulling levers and buttons here and there. Although the LQ has his limits (I’m not going to print any photo with it) it provides enough possibilities to my print needs, and, as I can witness, it’s a very sturdy, cheap maintenance and reliable device.

Long live the dot matrix printers!!!

Using an old trackball

Last fall, I got tired of my old MacBook and decided to donate it. So I bought a tiny and cheap MSI Cube and installed Fedora in it. I used to work with Ubuntu years ago, but I read some articles about Fedora and decided to give it a go. And I’m enjoying it!

I’ve been using a Magic Trackpad with the MacBook, but I didn’t get used to it in Fedora, mainly because all the functionalities that this kind of device provides can’t be exploited. I also tested it at work, but meh. So, I sold it to a friend. Time to look for a new mouse!

After lot of time wasted in watching mouse reviews and almost spend a fortune in an ultra-mega-hyper ergonomic one, I looked into the second hand market and saw one of this:

I said to myself: “Why not?”. And, finally, last week I purchased a pre-owned Logitech Trackman Marble FX for just 20€. Yes, this trackball is not pretty and is a little bit outdated, but you will change your mind after 5 minutes of use. It’s very confy and surprisingly accurate. In a couple of days, I started to think that I had lost too much time and money in mouses and trackpads.

This device is old and its connection is PS/2, so I had to use a PS/2 converter that I had laying around. But as usually, linux didn’t recognize it, so I needed to buy a cheap PS/2 to USB active converter and bingo! It started to work right out of the box… except the little red button… It’s not being detected, but, I can live without it. At least it has left, middle and right buttons. The only problem that I’m trying to solve right now is a big one… the scroll. I haven’t be able to activate any button to trigger the scroll functionality (as this trackball hasn’t got a scrollwheel or scroll ring) and any configuration I’ve tested so far hasn’t work. If somebody has one and is kind enoguh to help me, I’ll be very grateful!

Meanwhile, I’ll continue to move the ball with my index and middle finger (by the way, I think way better than use a trackball with the thumb).

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