Category Archives: electronica

Detallista.

Original en Chino ( traducido al inglés acá ).

La última vez que se me cayó la baba de semejante forma con un aparato electrónico fue cuando intenté (sin éxito) de reparar el equipo de rayos x en el cig. Releyendo mails viejos me encontré con el reloj de este señorito. Tiene todo para dejarme medio bobo por un buen rato. Es un reloj, tiene tubos nixie (no de los mas interesantes pero tubos al fin), y el diseño es exquisito pero sin descuidar la funcionalidad. Hasta me gustan los led en las bases, algo que siempre desprecié.

 

Interfaz de potencia

Recién terminé de rutear la plaqueta para un proyectito que empezamos con Crear. Nada de otro mundo, un registro de desplazamiento, optoacopladores y triacs. Usé la suite gEDA junto con unos scripts de Kai-Martin-Knaak. En el portátil tarda algo para hacer el render “fotorealístico” pero para mostrar el producto aún antes de que exista son geniales.

Interfaz midi simple con arduino en media hora.

Hace un par de semanas con los compañeros de Crear compramos un Arduino (y un montón mas de cosas en adafruit), llegó muchísimo mas rápido de lo que esperábamos. Mientras bajaba el ide empecé a trastear y en media hora ya estábamos controlando Ardour. El sketch es recontra simple, está basado en arduimidi/ttymidi

Hablá mas fuerte que no te escucho.

Hoy necesitaba despejarme un poco así que aproveché para ir hasta La Plata a comprar unas cosas de electrónica que precisaba, y tomar aire unas tres horas. La que lo tiró, cuánto tiempo que se pierde en el colectivo.

– Buenas, dame por favor ocho bt137

– Dos?

– Ocho

– Diez?

– OCHO!

Así siguió la cosa por otros quince minutos. Ni a propósito les sale tan bien.

French polish

“9.7 out of 10 doctors approve it”

Posiblemente muchos mas considerando como se sienten mis articulaciones luego de un ratito con esta pieza pequeña. Nada importante, un trozo cualquiera de madera de pino para darle un toque de distinción al programador de avr’s que hice hace un tiempo.

La cosa marcha (creo) bastante bien a pesar de no seguir estrictamente la tradición. Primero sellé la madera con un poco aceite de tung que tenía y luego con aceite común de cocina porque no vale la pena gastar mas en una madera de tan poca calidad. En lugar de una muñeca bien hecha usé brocha, algodón y gasa, yeso molido para emparejar la superficie.

Así quedó con cinco manos y una pulida:

Nerd weekends rock

Would you rather spend the weekend partying with amusing strangers or doing geeky stuff? Happy as never with my shiny new and photocopied books (Principles of Communications by Ziemer being the most notable and a bunch of theses) I chose the latter. Also I played with some brushless motors and field oriented control.

To make things worse (?) every single attendant to the party confirmed that my weekend was funnier than theirs.

Controlling an LB1946 via usb with an AVR

The LB1946 is a very nice chopper driver, the only downside is that it has a serial interface. So, for a project I need to control some steppers. I have a box full of printer boards, picked this one from and old epson inkjet because it had the same chips and also looks like I can chop it in half with a hacksaw and use them as they are.

The logic and the original power supply were toast so I used another I had at hand. To make some tests I hacked the PowerSwitch circuit from Objective Development to send raw commands and spin the motor with an usb interface.

At the end it doesn’t look quite like the original but it works. Still can’t get more than 1000 steps per second but I think that’s because of the supply. Now that I have the basic code working I’ll have to make a parallel interface so I can use them with EMC.

Sourcecode / References:

Pics:

Ode to reliability.

Or 11 years moving packets back and forth.

These are the remains of ‘Cachafaz’. It’s a very special computer for me. We bought it in 1999, it was my third computer, the second I’d put Linux into. Back then i called it ‘Garchake’ because I was using Mandrake. Lots of memories spring back… my first steps in C, hacking xmms plugins, countless hours playing Unreal Tournament (with windows ME, ewww). Amoung our friends it was pretty beefy, amd k6-3 400Mhz, 512Mb, 10gb hd plus the 2gb disk from my older computer, 56k modem and a Voodoo 4500…

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LCD Lightbox

It costed almost nothing but some screws and metal angles. Things I picked up from the street / junk:

  • Glass
  • Wooden angles
  • Old Acer laptop, not worth repairing. For this I took the screen only. Touchpad, drives and some other things left aside for another project.

Things already on hand:

  • Scanner (umax 1220p). I used its inverter because the one from the screen was broken. It served me well but the mirrors are very frayed, there’s moisture in the ccd and besides that it needs a parallel port, wich I don’t have at the moment.

Looks like something from the trash? Why yes! And I like it that way. It runs happily with anything between 7v and 20v (all the power bricks laying around) and as a nice side effect that lets me select the color temperature from a mild pink to a colder white.

Transformador de aislación II

Ya casi lo termino… (vine de acá). En la semana terminé la madera del tope y emprolijé las derivaciones. Ahora me falta nada más ponerle un portalámparas para la serie.

Evolución.

We devised a LOGO-like antenna constructing programming language where each node in the tree-structured representation is an antenna-construction command. An antenna is created by starting from the root of the tree and executing the commands at each node in the tree. In constructing an antenna, the current state (location and orientation) is maintained, and subsequent commands add wires or change the current state. We then used a genetic algorithm (GA) to evolve genotypes that specify the design for one arm, and built the complete antenna using four copies of the evolved arm.

http://ti.arc.nasa.gov/projects/esg/research/antenna.htm

Junkyard bug.

This morning while going to our doctor for a quick check I spotted some junk at an electronic shop in the neigbourhood. Tonight I just went there and brought with me an inkjet printer and part of a tv. The outcome of the printer was pretty much the usual, motors, gears, steel rods… the power supply is very nice and looks safe in it’s metal cage. The tv will give me a lot of materials for the next rf rig I’m building. Also it has some switching transformers, fast diodes and beefy capacitors. Sadly the tuner isn’t as modern as I hoped.

burned.

Spent the last 9 hours reading for the second time the books of Balabanian and Warzanskyj about network theory and synthesis. Not only most of the stuff (finally!) makes sense to me but i’m starting to feel a bit aroused with phrases like “general passive one ports”. Enough is enough, time to get some sleep. Also, Ursula 1000 is being played a lot on SomaFM, like thrice an hour but it never bores me.