Monday, August 29, 2011

Project of an HV physical switch

In these days I've designed using Google sketchup a possible use of one of the hydraulic cylinders: an HV switch! actually, i don't even know if it is an intelligent idea to use such a complicated thing, maybe there is a better solution °°, anyway these are my first steps in HV world, so i will be VERY careful,here's the first image:

the idea is simple: when i activate the cylinder it rises up fast, connecting the two contacts, the strange thing in the center of the pipe is a shield to avoid that the switch will act like a condenser: the two plastic sheets with between them a metal grid will considerably decrease the "condenser effect".
I'm also working on a idea of a diy HV capacitor bank,  charged with a MOT taken from an old microwave, but i'll talk about it in another post :D
in these days I won't update this blog very often because I'm studying for a physics exam, lol
again, but never enough, thanks to all for supporting =)

Tuesday, August 23, 2011

Coming next

I'm here with some components on the table thinking of what to do next, here's the idea :D

I'll use the three hydraulic cylinders i have:

 I'm thinking if designing a simple arduino shield to drive them, using this valves:

It's great to have things like these, if I hadn't got them, they would have been thrown away, only because the factory was doing some cleaning up °° such a waste.
I think I'm going to use them in a high current switch, because I'm planning of building some HV project thanks to the tutorials I've find in this site :D a madness like a Jacob's ladder will be great ** i'll keep you updated ;)
other ideas? 

Saturday, August 20, 2011

Stepper driver arduino

As I promised, here's the circuit diagram of the stepper driver I've used(the .sch link is at the end of the post):

 for make all the thing more understandable, I'll make a little summary :)
firstly, here's the circuit: (the same of the older post, but now with the pinouts)
the idea is really simple: to drive a stepper I need to power the coils in the order explained in this post, the best idea is to use a h-bridge, thanks to this i can drive the motor with just 4 logical pins.
the chip that you can see in the picture is the l293 a dual h-bridge ( a h-bridge can invert the current in a coil, so to drive a stepper i need two of these ) the connections are pretty basic, it has two power pins, one for the logic supply, taken from the arduino board (5v) and the other for the stepper supply, taken from the connector; the 4 input pins are connected to the logical pins 5-6-7-8.
I've modified a little the classic scheme: the two enable pins of the l293 permits to decide the power given to the motor, so I connected them to the pins 9 and 10, so it's possible to drive them with a PWM signal :)
in the next days I'm making more experimentation with the capacitive sensors, but i think I'll use a dedicated chip =)
thanks for supporting :D

Wednesday, August 10, 2011

CapSlide hardware beta version

I'm back with great updates :D I've almost finished to design the hardware to drive the steppers, I've called it CapSlide, because it uses a capacitive slide sensor to drive a stepper motor; firstly I'll show you the simple shield I've used to drive the motor, here's the thing:
the circuit is very simple,is a classic use of the l293, I'll post the scheme as soon as possible :), for now, here's some pictures of  the circuit:

 Top view:

Saturday, August 6, 2011

CapSenseTest first version

just finished to making the house livable, sorry for the period of complete silence ;)

As i said before, I've designed a simple application in processing to test the response of the capacitive sensors, the arduino just arrived,so i hope that in the next days the whole thing will be finished :D
For those who doesn't know Processing, it is an open source graphical Java library that uses a (little ) simplified Java grammar, is designed for visual artists and whoever needs a simple approach to guis,for those who are interested is also possible to import all the files in editors like Eclipse, and so on, here for more info.

So, reading this manual i've decided to design an application  for test the capacitive sensors of my project about the steppers, the idea is  simple: a graph showing the last mesurements and a bar tho show the instantaneous capacitance, surely there are lots of java libraries to do this, but i've decided to use processing and building all the gui from the beginning, why? because processing seems funny, because i was without an internet connection and the eas way doesn't always give enough satisfaction ;)

firstly i've designed two objects the graph and the bar, here's a summary (the link for code of the whole application is in the end of the post, after the break)

Monday, August 1, 2011

live from Greece

Wooah! i've just managed to be connect with a decent wifi! in the previuos campings was impossible >.< i'm preparing an interesting java application to test the circular sensor for the stepper project :) i've designed from the basics a class that reads the data from a serial connection and shows it in a gui, it's useful to make little adjustments and have the whole thing working perfectly, in the next days i will post all the code with the explaination, i'm still trying to improve it and making readable

Friday, July 22, 2011

last updates before holiday =)

Tomorrow i'm leaving for half a month for a trip in Greece, so i'll let you know my last progresses in my projects :D

Firstly, i've added a little preamp in the scheme of my sound effect, because the current taken by the central coil isn't enough to transmit another time the sound, hope it will works =) one or two transistors in cascade should be fine;

I've prepared an interesting project using the stepper motors, for people who have no idea of what a stepper is, i'll make a simple explaination:

Stepper motors are motors whose internal design permits to have extremely precise movements, for example, one of the steppers i've reviewed in my first post has a deg/step rate of 1.8° this means that to have a  complete round needs to make 360/1.8 = 200 steps!

The idea was to drive a stepper using an arduino and a h-bridge  chip, the chip is needed because as you can see in the stepping sequence you need to invert the current flow, not so easy only with transistors and logical ports.

I spent the last week looking for a cool way to say to the arduino what to do with this motor, and then yesterday, the idea!! : reading about the arduino's libraries i've noticed one: the CapSense libary that permits you to transform an aluminum foil in a sort of touch button,it works also trough materials like plastic or paper! using google Sketchup i've designed a simple circular touch sensor: