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16  Forum 2005-2010 (read only) / Interfacing / Cross-platform reading of a text file into Arduino on: February 26, 2009, 11:58:14 am
So, quick background, I'm just capable enough on Arduino to get myself into trouble, and used to program Visual Basic, but it's been a good 10-15 years or so.

I'm trying to find the simplest cross-platform (Mac and Windows) way to have a plain text file with, say, eight strings, separated by line breaks or commas, and send those to an Arduino over USB to be stored as variables in EEPROM so that they're non-volatile.

Is there a way to do this in a browser, or some other simple cross-platform way? I would love to be able to just have a web page that you could type in the eight values, connect the Arduino, and hit a button to upload those to the Arduino.

The idea is that I'd program my little Arduino beast to send a different serial message out (MIDI, actually) when a different button on it is pressed, and I want to provide an easy way for the end user to program their own messages for it, ideally with minimal configuration on their end.

Possible, or pipe dream?

17  Forum 2005-2010 (read only) / Development / MIDI Analyzer/Tester on: February 24, 2008, 10:57:20 pm
Hey everybody,
I've found some examples here and elsewhere on getting MIDI into an Arduino and interpreting it, but am curious if anybody has written/knows of a program to use the Arduino as a MIDI tester/analyzer, similar to Paul Mesick's MIDI ViewPort? Basically creating a standalone version of MIDI Analser/MIDI OX (depending on your OS of choice :-)

If not, any pointers on doing so? I suppose the easy part is the analyzer, which is just a matter of translating the serial data into English messages and printing them to an LCD (well, easy as far as conceptually, scale of implementing the whole library of MIDI messages is another issue).

It gets slightly more complicated trying to implement a cable test into it, although I suppose only marginally so. The biggest hurdle I see, being a complete Arduino newbie, is how to use a serial LCD and output MIDI for testing purposes simultaneously.

Anyway, if anybody knows of anything existing, or has some pointers if I decide to dive in on my own, it'd be much appreciated!

18  Forum 2005-2010 (read only) / Interfacing / Re: works: MIDI-IN: code + schematics on: July 14, 2008, 12:51:50 pm
Does anybody happen to have a copy of the schematic for this? Unless it's just something weird on my end, the image from the original post is missing. Thanks!
19  Forum 2005-2010 (read only) / Interfacing / Re: Best approach for three-wire, two-way remote? on: May 10, 2009, 04:50:31 pm
Hey Ran,
No, no power existing, it has to be provided over the three conductors. It's actually a shielded twisted pair, a mic/line level cable with 3-pin XLR connectors, to be precise. Length isn't a huge issue, it only needs to be 10', although the ability to work over longer distances would be great.

20  Forum 2005-2010 (read only) / Interfacing / Re: Best approach for three-wire, two-way remote? on: May 10, 2009, 04:33:00 pm
I hope you didn't take my reply as putting down your response, LOL, I was just clarifying that I'm not married to having the Arduino in the remote, I'm equally open to some sort of interface board or any other option that others might have to suggest.

I wasn't sure if your post was "well, if you're going to have an Arduino, then this is how I'd do it," or, "Well, since you'll have an Arduino in there anyway, you might as well..." so I figured I'd clarify that the Arduino in the remote was only an option, not a given :-)

21  Forum 2005-2010 (read only) / Interfacing / Re: Best approach for three-wire, two-way remote? on: May 10, 2009, 03:17:25 pm
Well, the remote doesn't have to be an Arduino at all, that's what I'm trying to decide :-) It could be something simpler, or, in the case of the analog route, no processor at all.
22  Forum 2005-2010 (read only) / Interfacing / Best approach for three-wire, two-way remote? on: May 10, 2009, 01:34:25 pm
I'm working on a project which involves a wired remote connected to an Arduino, with 3 conductors available for the wire (out of necessity for utilizing an existing infrastructure). The remote will have 7 buttons, and a bi-color LED. I'm debating the relative merits of two approaches, and was hoping for some input from you guys.

1) All analog. The wires to the remote are input, 3V3, and LED control. The LED control line is connected to an output which goes either high (5V) or low, and the LED is connected between that and the 3V3 supply, so it sees a relative -2V7 or +3V3 to go either red or green. The switches each connect 3V3 to the input line via a different value resistor, which returns to an analog input, and then the Arduino reads the analog input to determine which switch is pressed. Multiple simultaneous button presses aren't an issue in this application.

2) Digital. The remote has an Arduino Pro Mini, and directly processes the buttons, and controls the LED, and connects to the primary Arduino via I2C or some other method tbd.

Any thoughts on either approach? Clearly the analog method is more elegant and cost-effective, but I'm concerned about being able to get all 7 inputs that way. I see discussion here on doing this sort of "analog multiplexing" somewhat often, but always with just a mention of having to "carefully choose" values for the resistors, but never discussion of what to take into account when choosing them/what values to use. Clearly I'd use thresholds for the reads rather than discrete values, to allow for fluctuations in readings (and appropriately Aref to 3V3).

My other concern with this method is the stability of the analog inputs/their susceptibility to noise.

If I go the digital route, are there any suggestions for the best way to interface the two Arduinos? Or is there a simpler board, sort of a wired XBee, to use for the remote? I only need to pass which button is pressed, and ideally to control the LED in the other direction. Is I2C the best way to go? Roll my own through some other method?

23  Forum 2005-2010 (read only) / Interfacing / MIDI Out w/ 3.3V board (and related PSU question) on: April 28, 2009, 10:27:16 pm
Hey guys,
Quick question re: MIDI out from an Arduino, as per:

I'd presume the general solution to doing this with a 3.3V Arduino board would be to use the +3.3V rather than +5? This technically isn't kosher with MIDI spec, which specifies +5, but since it's a current loop and inputs are opto-isolated, should be ok, right?

A quasi-related question, f I wanted to, could I connect to Vcc rather than +3.3V for pin 4 of the DIN?

My problem is that I'm trying to power the Arduino off the +5V from a MIDI device connected to the Arduino's input, but many MIDI device manufacturers don't actually observe the spec, and some run as low as 3.3, while others can (although rarely, I've never seen it, only heard rumor) be as high as 12V. So I'm trying to figure out the best way to cope with this. Connecting to Vcc would at least solve my problem, albeit I'd be passing the buck on the output side of life to whatever voltage the device I'm connected to is providing, which I don't love, but could deal with.

Otherwise, I need to start investigating a power supply circuit that I can use with a 5V Arduino that will either step up a 3.3V to 5V, or regulate something as high as 12V down to 5V. Or, I suppose, a step up to 7V, and that is happy passing 12V as whatever it comes out as, and then feeding that to the Arduino's regulator?


24  Forum 2005-2010 (read only) / Interfacing / MIDI Thru w/SysEx? on: March 22, 2009, 12:30:45 pm
Hey gang,
Is there anybody that can guide me towards how to create a MIDI Thru/MIDI Merge in Arduino? I was planning to use the MIDI Library, but I need to be able to both send and relay SysEx messages, and the Library doesn't support that, at least yet.

If anybody can help out in getting the Arduino to pass on any/all messages from the input, while merging its own messages, I'll be forever grateful!

Andy, still an Arduino-newbie :-)
25  Forum 2005-2010 (read only) / Interfacing / Re: Bi-color LED on one pin... on: February 28, 2009, 02:13:37 am
Except that I'm driving an analog input pin, not a digital input, so Schmitt or not, it's moot :-)

And aref can be set to the lower voltage, so I'm not losing half the resolution.
26  Forum 2005-2010 (read only) / Interfacing / Re: Bi-color LED on one pin... on: February 26, 2009, 07:59:55 pm
LOL, don't I wish. That'd make life soooo much easier. It's actually a handheld remote, and needs to connect via an existing cable run. Ah, the fun of challenges :-)
27  Forum 2005-2010 (read only) / Interfacing / Re: Bi-color LED on one pin... on: February 26, 2009, 06:59:35 pm
Macgruber, this won't work in my situation, because it requires an additional pin. Because I'm limited to three lines to the control panel, I don't have any way to get a dedicated ground.

I already need the + and analog in for reading the buttons, which ties up two of my three lines. So I only have one other pin available to make the magic work; ie, I have my + and one control line available for the LED, so the only way to make it feasible is to make either the + or the control line be the "ground" for the LED.
28  Forum 2005-2010 (read only) / Interfacing / Bi-color LED on one pin... on: February 26, 2009, 06:15:33 am
Hey guys,
So, this may be a stupid question, but at 6am, I want a second opinion, LOL...

I'm working on a project where I've got three lines available to a control panel that needs to read multiple buttons, as well as light a bi-color LED in either of the two colors (it never needs to be off, FWIW).

I've got a handle on the buttons, I'm going to do the analog "multiplex" thing with appropriately selected resistors so that I can just feed V+ in from the Arduino, then the switches will connect their respective resistors between V+ and an analog input.

So that ties up two pins, one with V+, and one for the input. I think I have a way to get the LED working with the remaining pin, but just want to make sure I'm not doing something stupid.

My theory is (being 6am and half-functioning, I'll gloss over the current-limiting resistors for now, and come back to the math once I'm sure the basic concept is valid) that I can use +3V as the supply voltage for the control panel, and then the LED will go between the 3V and a digital output.

If I set the output low, then the LED will see the +3V relative to the low output's ground, and light up green.

If I set the output high (ie, +5V), then the LED sees the +3V relative to the high output's +5V, for a potential of -2V compared to the low state, and would light up red.

Will this work, or am I missing something really stupid in my overtired state?

Thanks in advance,
29  Forum 2005-2010 (read only) / Interfacing / Rudimentary Resistance Meter on: March 27, 2008, 09:11:50 pm
Hi everybody,
I'm trying to use an Arduino as a relatively simple go/no-go resistance meter, to measure, for example, if a given circuit is either 2kOhm, 4kOhm, or significantly higher. My question is, can I do this by just sending the 5V through the circuit, and then returning it to an analog input and reading the voltage, which could then be compared to reference measurements?

An acquaintance suggested I'd need to use a voltage divider with resistors roughly matched to the resistance being measured, but I can't quite wrap my head around why that would be necessary in this situation, since I'd only be feeding the regulated 5V max to the input (if it were a dead short). Would that serve to narrow the range/increase the accuracy of the measurement? I almost want to say that it would decrease the accuracy, since less than 5V would be hitting the input at full, so it would never read full, right?

Am I missing something, or was he incorrect?
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