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1  Using Arduino / Installation & Troubleshooting / RX/TX Issues... on: March 08, 2011, 09:46:52 pm
I'm not entirely sure whether this should go in the Processing forum or the Arduino forum, but here goes. I was having some serious issues regarding data integrity over the serial connection between Processing and my Arduino. Finally, I realized that it was because Processing was having a conflict with my RX/TX drivers. I updated the drivers, and all of my problems were solved. Or so I thought...

Well, my Processing code worked, so now it was time to make some additions to the code I had running on the Arduino. Except...the Arduino environment crashes every time I go to upload code.

My best guess is that updating my RX/TX drivers broke the Arduino dev environment. I need the old drivers to upload my code to the Arduino, but I need the new ones so that I can communicate with it. Of course, I don't even know what version Arduino was using.

I am stuck between a rock and a hard place. Can anyone help me? Is there any way to load different RX/TX drivers in Arduino and Processing? Can I get Arduino to play nice with the new drivers? (rxtx2.2pre2)

P.S. The error report won't fit. Not sure how to include it.

:edit: I deleted my RX/TX files entirely, and now everything is fixed. I guess Processing and Arduino come with their own drivers to fall back on just in case the user screws something up royally. :/edit:
2  Forum 2005-2010 (read only) / Interfacing / Re: Reading/writing to a 32 pin EEPROM /w Duemilanove on: June 19, 2010, 02:31:09 am
One thing is bugging me. I'm going to need an I2C interface for each of these, right? Does the Wire library support using multiple I2C devices at the same time? Am I going to be able to configure the Arduino to use two of these simultaneously?

:edit: Nevermind, some Googling answered my question. Never worked with I2C before. This is pretty boss. :/edit:
3  Forum 2005-2010 (read only) / Interfacing / Re: Reading/writing to a 32 pin EEPROM /w Duemilanove on: June 19, 2010, 02:09:35 am
Thanks a ton. These will make my life a whole lot easier. Found out the hard way that shift registers with serial and parallel I/O are basically non-existant.
4  Forum 2005-2010 (read only) / Interfacing / Re: Reading/writing to a 32 pin EEPROM /w Duemilanove on: June 18, 2010, 12:16:28 pm
From what I understand, the cartridge is mostly just a fancy interface. It's got some address pins, some R/W pins, a R/W toggle, power, ground, clock, and one or two other miscellaneous pins. It only has two chips other than the ROM. One is a memory controller, and the other is a watch-battery powered save game RAM.

All of this stuff is fairly well documented. I just hope it's as easy as it sounds. The most challenging part will probably be modifying the cartridges. Thanks for the reassurance.
5  Forum 2005-2010 (read only) / Interfacing / Reading/writing to a 32 pin EEPROM /w Duemilanove on: June 18, 2010, 11:59:18 am
I am attempting to construct a Gameboy cartridge reader/writer for homebrew development. I plan on using the Duemilanove because I'm a student, so I'm strapped for cash, because I would like to use it for future projects, and because it's a nice, flexible development platform. I've taken a logic design course, I am fluent in C/C++, I'm familiar with assembly, and though I haven't done much circuit design, my work in a robotics lab has made me quite handy with a soldering iron, and I've got some basic electronics know-how.

Flash cartridges are normal Gameboy cartridges whose ROMs have been refitted with EEPROMs. They can be written to via the 32 pins on the cartridge itself. My plan is to salvage a Gameboy cartridge slot, rig up 8 daisy-chained shift registers to that, and then interface those using the Duemilanove's IO. The Duemilanove will essentially be a serial-parallel/parallel-serial interface between my computer and the EEPROM in the gameboy cartridge.

I want to do this so that I can write software for the Gameboy and so that I can finally make good use of my copy of LSDJ (music software for the Gameboy). I could use a schematic from some site, but I don't trust the old designs that are out there, and I figure that this will be a valuable learning experience and a fun summer project.

What I'm asking for from you guys is whether this is a feasible project and will it work? Despite my claim to taking a course in logic design, I really haven't spent much time working with shift registers, especially using them to multiplex I/O, but if it can be done, I am confident that it won't be too hard to figure out.

Thanks. :]
6  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Some help regarding a project I'm working on? on: August 11, 2010, 01:52:26 pm
@P_Wood: I believe that I've seen a few projects that use squishy buttons like that to depress tactile switches. I didn't spend much on the switches anyway, so if it doesn't work well, then I'll just find some other way to get input. I'm going to make a 4x4 or 2x2 test build before I construct the whole thing anyway. I've seen the Sparkfun button pads, but those can get expensive quick. Arrogant as I am, I believe that I can find a more economical way to build a Monome-type device.

@Lyght: They can be found with a quick search for "vending machine capsules." Here's a link to a site that supplies them, though I've seen them for cheaper:

(FYI, I haven't got any yet. I'll post an update if/when I find a really cheap place to order them.)
7  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Some help regarding a project I'm working on? on: August 10, 2010, 01:22:46 am
Wow! That's cheap. I'm definitely going to use ebay for this. That works beautifully too, since the shipping is cheaper AND Digikey doesn't accept Paypal. Thank you so much for the help and info. I'm glad you like the idea, and I will make sure to keep everyone posted.

:edit: Just bought my Arduino and spent my remaining $20 Paypal balance on 100 6mm momentary switches, 100 18000mcd green LEDs, 5 SI/SPO shift registers and 4 multiplexer/demultiplexer chips. All of it should arrive within the next two weeks. I'm quite excited. Also, I get a whole bunch of free resistors with my LEDs. Thanks ebay/MikMo! :/edit:
8  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Some help regarding a project I'm working on? on: August 10, 2010, 12:22:57 am
@zoomkat: Have you looked at the prices of illuminated pushbutton switches on Digikey/Mouser? If I wanted to spend $300+, I would just buy a Monome kit.

@MikMo: Yeah, I'll probably end up doing that. I don't have enough cash right now to order everything I would need anyway. I'm just going to pick up some stuff for my parallel EEPROM reader/writer and a couple of components here and there to mess around and prototype with in the meanwhile. Then maybe I can save up enough to do a 256 LED matrix.

Also, I have decided how I am going to construct the LED buttons. My GF actually came up with this. As an artist, she's amazing at finding weird, awesome crap to re-purpose.

You know those capsules that cheap vending machine toys come in? The small ones? You can buy those in bulk for super cheap. (1000 for $40, for instance)

Sandpaper the capsule to diffuse the light from the LED, glue the base of the capsule on permanently, drill a hole in the base so that the LED can fit through, and mount a momentary switch on the side to be pressed down by the base of the capsule.

Then all that's left is to build a plywood/acrylic cover for the capsule button tops to stick out of.
9  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Some help regarding a project I'm working on? on: August 08, 2010, 11:07:02 pm
Isn't Radioshack ridiculously expensive? And pushbutton switches with embedded LEDs run for about 3$ a pop. I don't have 300$ to spend on switches alone. If you know of somewhere where I can get these for cheap, let me know.
10  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Some help regarding a project I'm working on? on: August 08, 2010, 06:39:12 pm
I need so many LEDs because I need an 8x8 button/led combo matrix (like the monome) plus extra status LEDs and buttons for miscellaneous stuff. I don't know what LEDs to buy though. Not sure whether I should just go with the cheap 25pc LED kit from Sparkfun to save on shipping, or whether or not it would be cheaper to get stuff off Mouser or Digikey. I also don't really have a good idea of how bright certain LEDs are going to be.

Also, I don't really understand what benefits an LED driver chip offers over a register. Is it just built to accomodate higher loads? I guess the simplest explanation of the project is that this is going to be a whole lot of LED/pushbutton pairs so that I can adjust and monitor the state of my live performance software quickly. The LEDs need to be bright enough to be clearly visible in moderate indoor lighting.
11  Forum 2005-2010 (read only) / Frequently-Asked Questions / Some help regarding a project I'm working on? on: August 08, 2010, 01:29:48 pm
I am trying to build a custom interface for the live performance (music) software I've been writing, but I'm somewhat overwhelmed. I'm going to order a duemilanove for this project and some other prototyping, but that's about as far as I've gotten in terms of ordering hardware.

Right now I am using my Korg padKONTROL (seen above) as an input device, but I want something larger and more customized, and I am trying to do this as cheaply as possible. I have eventual access to a laser cutter, so I was thinking I would pick up some acrylic sheets, some plywood, some LEDs, momentary pushbutton switches, some I/O multiplexing equipment and get started.

However, I don't know exactly what I need. I am thinking somewhere between 92-128 LEDs and a similar number of switches, but I don't know what LEDs/switches or where to order them from. I don't know how to know how bright the LEDs will be or how they will work in places with high ambient light. I also don't know whether or not I should try to multiplex the arduino I/O or if I should get an LED driver and some parallel-in/serial-out shift registers instead. Or maybe some I2C I/O expanders like I am going to use for my gameboy flashcard reader/writer project?

Like I said, I'm just a bit overwhelmed. I've done a lot of electronics work, but I've never built anything from scratch like this before. I'm hoping that some of the more experienced members can help me find a functional, affordable way to build this.


Also, for anyone in the know, I am currently using the padKONTROL in native mode. I would be communicating with the Arduino via plain old serial, not as a MIDI device.
12  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Simple momentary switch idea: Will this work? on: July 28, 2010, 07:38:33 pm
I have to get some money in the bank and order my Arduino first. Metal contacts would greatly simplify the build. Prolly just bite the bullet and buy some switches though.
13  Forum 2005-2010 (read only) / Frequently-Asked Questions / Simple momentary switch idea: Will this work? on: July 27, 2010, 01:16:14 pm
I'm somewhat new to the hardware side of electronics, and need to build something with ALOT of momentary switches using the Arduino. I'm poor enough that even buying a bunch of momentary switches is going to make a nasty dent in my wallet. However, I've seen people use nails and other bits of metal as crude electronic interfaces, and I want to know whether this will work.

--- My Idea ---

Take something conductive. Like a nail. Connect (low, preferably) voltage to it, and then add a pullup resister going from the nail to an I/O pin. When nothing is touching the nail, the I/O pin should be high because the electricity has nowhere to go but through the resistor, but when my finger presses the nail, the electricity follows the path of least resistance down my body into the ground. The I/O pin goes low, signifying a touch.


I figure if all I have to buy is an LED driver, some LEDs, and some multiplexing chips, I can make something similar to a Monome for about 50$ using some spare acrylic/plywood and some metal contacts. But that only really works assuming that my idea isn't completely stupid and won't result in a dead Arduino.

Other benefits are that the construction will be infinitely easier, neater, and more durable this way. Metal contacts won't get nasty, or stuck, or break. It's going to be part of my live performance rig, so this is really ideal.

P.S. I know about capacitive sensing, but it's going to be slow for over 64 contacts. I would prefer to do things this way.
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