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46  Development / Other Software Development / Re: Forth programming language? on: November 15, 2012, 07:03:19 am
Has been discussed in the forum, do some browsing & see how far it went.


Thank you for your useful answer.
Here's the link to the post you are referring to.
http://arduino.cc/forum/index.php/topic,8838.0.html

I read the whole post before opening a new thread. The post is from 1/2011 and, guess what, is closed!
And, as I said "Yet i could not find anything mature enough to be of simple installation and practical to use."

So my question still stands: Anyone knows of a good Forth implementation for Arduino?

Any useful answer would be greatly appreciated.


47  Development / Other Software Development / Forth programming language? on: November 14, 2012, 10:47:05 pm
I have a nostalgic attachment to the Forth programming language that I learned last century and never used.
I understand Forth is used in embedded systems (lego mindstorms is the only one that comes to mind right now) so I thought i would find an implementation for the most popular microcontroller development system in the world, i.e. Arduino.
Yet i could not find anything mature enough to be of simple installation and practical to use.

Anyone knows of a good Forth implementation for Arduino?

TIA
48  Development / Other Software Development / Re: vb 6.0 + supported.. on: November 14, 2012, 10:33:41 pm
Quote
possible to have it be compatible with vb 6.0 and newer?
What is "it"? A tennis racket? I don't think so.

A pronoun without a referent is pretty much useless.

"it" on an Arduino Forum?
Mmmm let me think... I got it, he is referring to the PIC !
Duh

49  Using Arduino / General Electronics / Re: Help on momentary push switches in series. on: November 14, 2012, 07:09:32 pm
Quote
R-2R networks only work with SPDT switches, not SPST push buttons.

Are you sure about that? smiley

With a r2r type button, you can read multiple buttons from one pin, and you can detect simultaneous presses as well.


Thank you for pointing me t R/2R networks.
I'm no expert (in fact i learned about it today) but from the wikipedia article it would seem they would work also with momentary pushbuttons.

The problem of the low separation of voltages still remains as the resolution, for 12 pins is:
5/2^12 = 0.00122V
50  Using Arduino / General Electronics / Re: Help on momentary push switches in series. on: November 14, 2012, 04:29:10 pm
Why did you start a whole new thread on this keyboard?


To pose appropriate questions in appropriate forum.

Sensor question in sensor, multiplexing in multiplexing, audio in audio etc.
It is the same project which has different aspects to it.
It is is moreappropriate I can ask All the questions in a single thread, but then we will have audio, multiplexing, programming, sensor etc. In a single thread in which most of the questions will not be pertinent.

It's kind of like when a patient comes to see me for an eye problem, a dermatologist for a skin problem and an OBGYN for, well, another problem smiley even if it's the same individual.

Also, while we are on the topic (forgive the pun) i found interesting partial answers to my questions in older posts, but they were closed so i could not follow up with questions or comments. Why close old topics? Most of them are relevant with current devices.

51  Using Arduino / LEDs and Multiplexing / Re: Recommendation on a 13+ inputs digital multiplexer. on: November 14, 2012, 08:02:14 am
Have you considered Repurposing an existing keyboard ?
http://rcarduino.blogspot.com/2012/10/five-dollar-synthesiser.html

Duane B


Hello DuaneB.
I was aware of your $5 Keyboard, it came up during my researches. It's amazing but it sounds a bit complicated. My project is simpler and I wanted to see if I can do it from the ground up.
fungus: The distance is not much (same room say) but cost is important (and when isn't? smiley).
I think I'll just go with 1 wire per push switch (plus common ground) for the time being and later explore Crossroads' RF option for true portability (I'll have to do some more research on that, any good tutorial out there?).


Thanks again

 
52  Using Arduino / General Electronics / Re: Help on momentary push switches in series. on: November 14, 2012, 07:46:01 am
That's what I thought.
And I came to the conclusion that with a resolution of 1024 on the ADC in theory you could wire up the circuit to implement a binary progression for 12 buttons  (No button =0, button 1=1 button 2=2, button 3=4, button 4=8 etc.), in practice, that is unfeasible as the difference between button presses will be only 1 value, or 0.00488 V (e.g. buttons 1,2,3 pressed = 7 [0.034 V] ; button 4 only = 8 [0.039 V]) which even with very tight tolerance resistors will be sensitive to tiny supply voltage fluctuations.

If someone can prove my logic wrong and give me an example of such a circuit I will be very happy.

Incidentally, I read a long time ago that the very first digital computers designs were based on the decimal system (the most intuitive to us humans) but they never got to work in practice because of the unreliability of detecting those differences in voltage. The binary system was eventually used because it's much easier to detect No-voltage/voltage.

I feel like I re-discovered the wheel.
 
53  Using Arduino / Sensors / Re: Increasing sensitivity of a simple resistive touch sensor on: November 13, 2012, 03:57:22 pm
Thanks for your reply.

I have attached a sketch (in the original meaning) of what I am doing.

I was going to experiment with the capacitive sensor, but my understanding is that it is too sensitive sometimes activating with proximity instead of touch. But I have not tried that yet, so there may be a way.

54  Using Arduino / General Electronics / Re: Help on momentary push switches in series. on: November 13, 2012, 03:32:20 pm
That's an interesting idea!

The node on top is connected to +5, right?
Then the circuit acts as a voltage divider with each switch press bypassing a resistor and decreasing the total resistance.
But if the resistors have all the same value, can the program tell which button is pressed or only how many are pressed?
What's the value of the capacitor?

And, can you post the link to the playground article?

Thanks

55  Using Arduino / General Electronics / Re: Help on momentary push switches in series. on: November 13, 2012, 02:48:53 pm
Thanks!
56  Using Arduino / LEDs and Multiplexing / Re: Recommendation on a 13+ inputs digital multiplexer. on: November 13, 2012, 02:23:27 pm
Thanks again for the replies.

Crossroads: The "Wireless route " was going to be my next step (if I can make the whole thing work with wires, that is). I was thinking bluetooth but I don't know if there is a module for this and even if there is, what would be the simplest solution, Bluetooth or RF?

fungus: I was not aware of that, thanks for pointing it out.

57  Using Arduino / General Electronics / Re: Help on momentary push switches in series. on: November 13, 2012, 02:11:20 pm
However the simplest method to wire up buttons is to turn on the internal pull-up resistors in your sketch software for each pin you are using and wire a ground to the other side of each of the switches.

Thanks for the quick reply!

I came across this before but I am confused as how it works and how to turn on the internal pull up resistor
Can you give or point me to an example?

Thanks
58  Using Arduino / LEDs and Multiplexing / Re: Recommendation on a 13+ inputs digital multiplexer. on: November 13, 2012, 01:39:05 pm
Thanks for the quick reply!

The keyboard needs to be relatively free to be carried around on stage, much like a singer with a microphone and I thought reducing the number of wires will help accomplish that.

Your solution is feasible and I think I may end up doing something like that.

I was thinking to use RG5 (Ethernet) cables, either 1 cable (8 wires) or 2, if the multiplexer idea goes nowhere.

BTW, what is "PCINTs " is it something to do with interrupts? If so, this is a topic I avoided so far, but I may have to deal with it, can you point me to a good tutorial/book etc.?
I use PC (not Mac).
I was planning to scan the inputs quickly in my program, but maybe there is a better way.

Thanks again
59  Using Arduino / General Electronics / Help on momentary push switches in series. on: November 13, 2012, 01:27:26 pm
Hello,
  I am building a 13 keys jeyboard, the keys being momentary push switches).

The keyboard is not going to be close to Arduino so I want to cut down on the amount of wires going back and fort from him (Arduino).

I came up with two possibilities (see picture)
The one above should work at rest (nothing pushed) but I fear that if you close any switch, all pins will go high. Am I correct?

The second one should work but I am using 13 resistors in parallel. Do I need to increase the resistance of each 13 times? That is using 13 120 K resistors (not sure if I have 130 K) ?

Also, Arduino need to be able to sense the pressing of any combination of buttons (up to 10 at a time, for a standard 10-fingered player).

Your comments will be greatly appreciated.

Thanks

Thot

P.S. Sorry for the quality, I am not Forrest Mims III  smiley and I don't know (yet) how to use CAD software.

60  Using Arduino / LEDs and Multiplexing / Recommendation on a 13+ inputs digital multiplexer. on: November 13, 2012, 01:05:49 pm
Hello All,
         I am playing with a 13 keys keyboard project (the keys are made by momentary pushbuttons)  to drive an Arduino Uno and I was wondering if someone can recommend a single multiplexer IC that can accept 13 inputs or more.

I know Arduino can accept up to 14 digital inputs but since the keyboard is going to be far from the Arduino, my goal is to cut down on wires going back and forth by putting a small daughterboard with the multiplexer on the keyboard and run back and forth from Arduino: Power, Ground, the output from the multiplexer and however many wires Arduino needs to select the multiplexer port (4 probably as 2^4 = 16).

If you have any suggestion of a multiplexer, and where to buy them, I would greatly appreciate.

Thanks

Thot

P.S. I searched the forum but I mainly found references to an 8 port multiplerxer. I could use two, but that would partially defeat the purpose on cutting down on wires going back and forth from Arduino and make it for a bigger daugherboard.



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