this is more or less a copy of a thread ive started at the arduino forum:

im going deep with a dj controller project and faced an old enemy. the potentiometers and their high cost (for a no budget project)

bythe way im talking about variable resistors!

well ive learned that there are some sollutions
here are my chosen:

• salvage potentiometers from old electronic equipment like stereos and stuff (takes time, lack of standards in equipment)
• build your own using a high resistance material and a pointer to be the variable piece. (look for paper resistor)
• use old equipment from optical mice (optical encoders and stuff to track the rotation of an element which is locked so it cant go more than 360 turn)
• use salvaged parts from mechanical mice(same as the one above)
  both optical and mechanical mice have the option to be interfaced directly using the ps2 protocol, or the actual used parts can be taken out)
• use some kind of motor that gives output when it turns (reversed motor for rotation input)

thats about it.
for info on the above look here:

fast sketch on the mice usage : 
http://img155.imageshack.us/img155/7006/opticalstuff.png

paper resistor:
http://www.instructables.com/id/Paper-Resistor/

ps2 mouse stuff:
http://www.arduino.cc/playground/ComponentLib/Ps2mouse
- http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1267532312/0

another thing is that i need to have more inputs than i can get from the few arduino ports.
here comes fluidforms to help on that. they have made a project describing just that here:

How did we make the Cassius Punching Bag
The Fluidforms Punching Bag contains a matrix of 9×7 force sensors that measure the force exerted by a blow to the punching bag. The sensors are plugged into an Arduino board that sends the values over USB to a computer using the MIDI protocol….
- http://fluidforms.eu/de/CassiusHow.php

No tags

today i made a project case for my arduino. i was getting too tired of having the arduino and breadboard allways jumping around because of being not mounted on stuff. so i took a look around and stuffed a breadboard plus arduino inside a vhs case:

i also stuffed a stepper motor inside so i could use the whole case for learning to program stepper motors in a steady environment.
it works like a charm and feels ok too, plus there is a lot of space unused inside where maybe a small usb cord plus some solid core jumper wires could be placed there.
to close the case it needs a piece of ellastic wire like a hair string or something.
here is some pictures to show it in function:

picture above shows the outer of the case with an arrow attached to the stepper motor and a paper sticker attached as scale.

here is a picture showing the entire project box:

here is a short tutorial on how to redo this project:

1. find a vhs case
2. drill holes like this
3. place arduino, breadboard and if you have a stepper motor lying around over the holes
4. put metal wire from the holes over the hardware to hold ‘em down. twist the ends of wire together
5. hook the arduino up with some programming and do something physical

No tags

here is a video clip showing the ability of video wall using the tiny vga diy boards and a controller to control the all. in my mind this opens up for lots of interesting opportunities.
check out

and here is a timelapse of a vga workshop taken from piksel i think

here is some info on a more neat version of the diy tiny vga board which is not to be mistaken of being the more costly pico vga and so forth.
http://scherpenisse.net/project/527/tinyvga
its very simple and consist of the following
1 x TinyVGA board
3 x resistors (2.2k)
2 x yellow capacitors (33pF)
1 x Crystal 20mhz
1 x IC socket
2 x black capacitors (0.1uF)
1 x LED
1 x Voltage regulator
1 x VGA connector
1 x 9V clip
1 x 4 I/O pins (for arduino)
1 x PIC16F628a microcontroller (preprogrammed)

No tags

i just found a nice and cheap tutorial at on-signal.org, on how to make a vga tester. a vga tester is a small circuit consisting of a chip that takes take of sync and image and some other stuff and outputs an image to the vga screen.
the chip itself takes care of the picture output so it should be reasonably easy to input the pixels from another chip, arduino for example, to several of these making a low resolution video wall.

Microchip micro-controller it’s possible to generate signals. With these signals you can display all kinds of pixel patterns on any VGA monitor or beamer. During the workshop participants will create their own “VGA test box” that will make it possible for you to do the same.

The micro-controller will be programmed using PIC assembly language, however, assembly coding skills are not required, as pre-programmed chips will be available, and participants can create their own image / logo for their test box. Participants do need some soldering skills. The more adventurous participants can use the prepared micro-controller to hook it up to an Arduino or I2C chip, so that the VGA signal can be modified using a more powerful computer

here is the source code and tutorial from on-signal.org:
Source code, docs, example files
Workshop instruction manual

No tags

from avr matrices onwards to doing it with the arduino. people must ask why, when you can buy the avr and code it for cheeper/faster hz without the arduino brand. but coding in processing is simply much easier than coding in c, plus you can obtain a workflow where both the code running on the board managing the physical control of the leds, and the design of what to show inside the same environment. in programming.
so. from there to the new point of no return

• “hello everyone,does anyone have an idea how to convert an image (jpg, png, etc.) to an LED-Matrix with processing?”
  - says Til over at the processing forums
• “I’m trying to create a 16×16 LED matrix. I was looking at the 8×8 matrices (http://www.sparkfun.com/commerce/product_info.php?products_id=682) and was wondering if I could use 4 of these to make a 16×16. I looked at the schematics but I couldn’t think of any way to do this off the top of my head.”
  - says Iros at the sparkfun forums. where a nice follow up on the possibilities guides me onwards to the mother solution of all solutions
• another place on sparkfuns forums, which im btw beginning to like pretty much!, i find a thread of 11 pages help regarding exactly my questions.
  
  

No tags